Build-ID processing goodies
---------------------------
Build-IDs are content based hashes to link regions of memory to ELF files
in post processing. They have been available in distros for quite a while:
$ file /bin/bash
/bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2,
BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a,
for GNU/Linux 3.2.0, stripped
It is possible to ask the kernel to get it from mmap executable backing
storage at time they are being put in place and send it as metadata at
that moment to have in perf.data.
Prefer that across the board to speed up 'record' time - it post processes
the samples to find binaries touched by any samples and to save them with
build-ID. It can skip reading build-ID in userspace if it comes from the
kernel.
perf record
-----------
* Make --buildid-mmap default. The kernel can generate MMAP2 events
with a build-ID from ELF header. Use that by default instead of using
inode and device ID to identify binaries. It also can be disabled
with --no-buildid-mmap.
* Use BPF for -u/--uid option to sample processes belong to a user.
BPF can track user processes more accurately and the existing logic
often fails to get the list of processes due to race with reading the
/proc filesystem.
* Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and
they have variables starting with "bpf_metadata_". This will help to
identify BPF objects used in the profile. This has been supported in
bpftool for some time and allows the recording of metadata such as
commit hashes, versions, etc, that now gets recorded in perf.data as
well.
* Collect list of DSOs touched in the sample callchains as well as in
the sample itself. This would increase the processing time at the end
of record, but can improve the data quality.
perf stat
---------
* Add a new 'drm' pseudo-PMU support like in 'hwmon'. It can collect
DRM usage stats using fdinfo in /proc.
On my Intel laptop, it shows like below:
$ perf list drm
...
drm:
drm-active-stolen-system0
[Total memory active in one or more engines. Unit: drm_i915]
drm-active-system0
[Total memory active in one or more engines. Unit: drm_i915]
drm-engine-capacity-video
[Engine capacity. Unit: drm_i915]
drm-engine-copy
[Utilization in ns. Unit: drm_i915]
drm-engine-render
[Utilization in ns. Unit: drm_i915]
drm-engine-video
[Utilization in ns. Unit: drm_i915]
...
$ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1
Performance counter stats for 'system wide':
48,137,316,988,873 ns drm-engine-render
34,452,696,746 ns drm-engine-video
20 capacity drm-engine-capacity-video
1.002086194 seconds time elapsed
perf list
---------
* Add description for software events. The description is in JSON format
and the event parser now can handle the software events like others
(for example, it's case-insensitive and subject to wildcard matching).
$ perf list software
List of pre-defined events (to be used in -e or -M):
software:
alignment-faults
[Number of kernel handled memory alignment faults. Unit: software]
bpf-output
[An event used by BPF programs to write to the perf ring buffer. Unit: software]
cgroup-switches
[Number of context switches to a task in a different cgroup. Unit: software]
context-switches
[Number of context switches [This event is an alias of cs]. Unit: software]
cpu-clock
[Per-CPU high-resolution timer based event. Unit: software]
cpu-migrations
[Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
cs
[Number of context switches [This event is an alias of context-switches]. Unit: software]
dummy
[A placeholder event that doesn't count anything. Unit: software]
emulation-faults
[Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software]
faults
[Number of page faults [This event is an alias of page-faults]. Unit: software]
major-faults
[Number of major page faults. Major faults require I/O to handle. Unit: software]
migrations
[Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software]
minor-faults
[Number of minor page faults. Minor faults don't require I/O to handle. Unit: software]
page-faults
[Number of page faults [This event is an alias of faults]. Unit: software]
task-clock
[Per-task high-resolution timer based event. Unit: software]
perf ftrace
-----------
* Add -e/--events option to perf ftrace latency to measure latency
between the two events instead of a function.
$ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1
# DURATION | COUNT | GRAPH |
256 - 512 us | 4 | ###### |
2 - 4 ms | 2 | ### |
4 - 8 ms | 12 | ################### |
8 - 16 ms | 10 | ################ |
# statistics (in usec)
total time: 194915
avg time: 6961
max time: 12855
min time: 373
count: 28
* Add new function graph tracer options (--graph-opts) to display more
info like arguments and return value. They will be passed to the
kernel ftrace directly.
$ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
...
5) | mutex_unlock() { /* <-rb_simple_write+0xda/0x150 */
5) 0.188 us | local_clock(); /* <-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */
5) | rt_mutex_slowunlock() { /* <-rb_simple_write+0xda/0x150 */
5) | _raw_spin_lock_irqsave() { /* <-rt_mutex_slowunlock+0x4f/0x200 */
5) 0.123 us | preempt_count_add(); /* <-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */
5) 0.128 us | local_clock(); /* <-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */
5) 0.086 us | do_raw_spin_trylock(); /* <-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */
5) 0.845 us | } /* _raw_spin_lock_irqsave ret=0x292 */
...
misc
----
* Add perf archive --exclude-buildids <FILE> option to skip some binaries.
The format of the FILE should be same as an output of perf buildid-list.
* Get rid of dependency of libcrypto. It was just to get SHA-1 hash so
implement it directly like in the kernel. A side effect is that it
needs -fno-strict-aliasing compiler option (again, like in the kernel).
* Convert all shell script tests to use bash.
Reviewed-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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Merge tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf tools updates from Namhyung Kim:
"Build-ID processing goodies:
Build-IDs are content based hashes to link regions of memory to ELF
files in post processing. They have been available in distros for
quite a while:
$ file /bin/bash
/bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2,
BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a,
for GNU/Linux 3.2.0, stripped
It is possible to ask the kernel to get it from mmap executable
backing storage at time they are being put in place and send it as
metadata at that moment to have in perf.data.
Prefer that across the board to speed up 'record' time - it post
processes the samples to find binaries touched by any samples and
to save them with build-ID. It can skip reading build-ID in
userspace if it comes from the kernel.
perf record:
* Make --buildid-mmap default. The kernel can generate MMAP2 events
with a build-ID from ELF header. Use that by default instead of using
inode and device ID to identify binaries. It also can be disabled
with --no-buildid-mmap.
* Use BPF for -u/--uid option to sample processes belong to a user.
BPF can track user processes more accurately and the existing logic
often fails to get the list of processes due to race with reading the
/proc filesystem.
* Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and
they have variables starting with "bpf_metadata_". This will help to
identify BPF objects used in the profile. This has been supported in
bpftool for some time and allows the recording of metadata such as
commit hashes, versions, etc, that now gets recorded in perf.data as
well.
* Collect list of DSOs touched in the sample callchains as well as in
the sample itself. This would increase the processing time at the end
of record, but can improve the data quality.
perf stat:
* Add a new 'drm' pseudo-PMU support like in 'hwmon'. It can collect
DRM usage stats using fdinfo in /proc.
On my Intel laptop, it shows like below:
$ perf list drm
...
drm:
drm-active-stolen-system0
[Total memory active in one or more engines. Unit: drm_i915]
drm-active-system0
[Total memory active in one or more engines. Unit: drm_i915]
drm-engine-capacity-video
[Engine capacity. Unit: drm_i915]
drm-engine-copy
[Utilization in ns. Unit: drm_i915]
drm-engine-render
[Utilization in ns. Unit: drm_i915]
drm-engine-video
[Utilization in ns. Unit: drm_i915]
...
$ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1
Performance counter stats for 'system wide':
48,137,316,988,873 ns drm-engine-render
34,452,696,746 ns drm-engine-video
20 capacity drm-engine-capacity-video
1.002086194 seconds time elapsed
perf list
* Add description for software events. The description is in JSON format
and the event parser now can handle the software events like others
(for example, it's case-insensitive and subject to wildcard matching).
$ perf list software
List of pre-defined events (to be used in -e or -M):
software:
alignment-faults
[Number of kernel handled memory alignment faults. Unit: software]
bpf-output
[An event used by BPF programs to write to the perf ring buffer. Unit: software]
cgroup-switches
[Number of context switches to a task in a different cgroup. Unit: software]
context-switches
[Number of context switches [This event is an alias of cs]. Unit: software]
cpu-clock
[Per-CPU high-resolution timer based event. Unit: software]
cpu-migrations
[Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
cs
[Number of context switches [This event is an alias of context-switches]. Unit: software]
dummy
[A placeholder event that doesn't count anything. Unit: software]
emulation-faults
[Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software]
faults
[Number of page faults [This event is an alias of page-faults]. Unit: software]
major-faults
[Number of major page faults. Major faults require I/O to handle. Unit: software]
migrations
[Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software]
minor-faults
[Number of minor page faults. Minor faults don't require I/O to handle. Unit: software]
page-faults
[Number of page faults [This event is an alias of faults]. Unit: software]
task-clock
[Per-task high-resolution timer based event. Unit: software]
perf ftrace:
* Add -e/--events option to perf ftrace latency to measure latency
between the two events instead of a function.
$ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1
# DURATION | COUNT | GRAPH |
256 - 512 us | 4 | ###### |
2 - 4 ms | 2 | ### |
4 - 8 ms | 12 | ################### |
8 - 16 ms | 10 | ################ |
# statistics (in usec)
total time: 194915
avg time: 6961
max time: 12855
min time: 373
count: 28
* Add new function graph tracer options (--graph-opts) to display more
info like arguments and return value. They will be passed to the
kernel ftrace directly.
$ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
...
5) | mutex_unlock() { /* <-rb_simple_write+0xda/0x150 */
5) 0.188 us | local_clock(); /* <-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */
5) | rt_mutex_slowunlock() { /* <-rb_simple_write+0xda/0x150 */
5) | _raw_spin_lock_irqsave() { /* <-rt_mutex_slowunlock+0x4f/0x200 */
5) 0.123 us | preempt_count_add(); /* <-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */
5) 0.128 us | local_clock(); /* <-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */
5) 0.086 us | do_raw_spin_trylock(); /* <-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */
5) 0.845 us | } /* _raw_spin_lock_irqsave ret=0x292 */
...
Misc:
* Add perf archive --exclude-buildids <FILE> option to skip some binaries.
The format of the FILE should be same as an output of perf buildid-list.
* Get rid of dependency of libcrypto. It was just to get SHA-1 hash so
implement it directly like in the kernel. A side effect is that it
needs -fno-strict-aliasing compiler option (again, like in the kernel).
* Convert all shell script tests to use bash"
* tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (179 commits)
perf record: Cache build-ID of hit DSOs only
perf test: Ensure lock contention using pipe mode
perf python: Stop using deprecated PyUnicode_AsString()
perf list: Skip ABI PMUs when printing pmu values
perf list: Remove tracepoint printing code
perf tp_pmu: Add event APIs
perf tp_pmu: Factor existing tracepoint logic to new file
perf parse-events: Remove non-json software events
perf jevents: Add common software event json
perf tools: Remove libtraceevent in .gitignore
perf test: Fix comment ordering
perf sort: Use perf_env to set arch sort keys and header
perf test: Move PERF_SAMPLE_WEIGHT_STRUCT parsing to common test
perf sample: Remove arch notion of sample parsing
perf env: Remove global perf_env
perf trace: Avoid global perf_env with evsel__env
perf auxtrace: Pass perf_env from session through to mmap read
perf machine: Explicitly pass in host perf_env
perf bench synthesize: Avoid use of global perf_env
perf top: Make perf_env locally scoped
...
It post-processes samples to find which DSO has samples. Based on that
info, it can save used DSOs in the build-ID cache directory. But for
some reason, it saves all DSOs without checking the hit mark. Skipping
unused DSOs can give some speedup especially with --buildid-mmap being
default.
On my idle machine, `time perf record -a sleep 1` goes down from 3 sec
to 1.5 sec with this change.
Fixes: e29386c8f7 ("perf record: Add --buildid-mmap option to enable PERF_RECORD_MMAP2's build id")
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250731070330.57116-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
- Host driver for GICv5, the next generation interrupt controller for
arm64, including support for interrupt routing, MSIs, interrupt
translation and wired interrupts.
- Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on
GICv5 hardware, leveraging the legacy VGIC interface.
- Userspace control of the 'nASSGIcap' GICv3 feature, allowing
userspace to disable support for SGIs w/o an active state on hardware
that previously advertised it unconditionally.
- Map supporting endpoints with cacheable memory attributes on systems
with FEAT_S2FWB and DIC where KVM no longer needs to perform cache
maintenance on the address range.
- Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the guest
hypervisor to inject external aborts into an L2 VM and take traps of
masked external aborts to the hypervisor.
- Convert more system register sanitization to the config-driven
implementation.
- Fixes to the visibility of EL2 registers, namely making VGICv3 system
registers accessible through the VGIC device instead of the ONE_REG
vCPU ioctls.
- Various cleanups and minor fixes.
LoongArch:
- Add stat information for in-kernel irqchip
- Add tracepoints for CPUCFG and CSR emulation exits
- Enhance in-kernel irqchip emulation
- Various cleanups.
RISC-V:
- Enable ring-based dirty memory tracking
- Improve perf kvm stat to report interrupt events
- Delegate illegal instruction trap to VS-mode
- MMU improvements related to upcoming nested virtualization
s390x
- Fixes
x86:
- Add CONFIG_KVM_IOAPIC for x86 to allow disabling support for I/O APIC,
PIC, and PIT emulation at compile time.
- Share device posted IRQ code between SVM and VMX and
harden it against bugs and runtime errors.
- Use vcpu_idx, not vcpu_id, for GA log tag/metadata, to make lookups O(1)
instead of O(n).
- For MMIO stale data mitigation, track whether or not a vCPU has access to
(host) MMIO based on whether the page tables have MMIO pfns mapped; using
VFIO is prone to false negatives
- Rework the MSR interception code so that the SVM and VMX APIs are more or
less identical.
- Recalculate all MSR intercepts from scratch on MSR filter changes,
instead of maintaining shadow bitmaps.
- Advertise support for LKGS (Load Kernel GS base), a new instruction
that's loosely related to FRED, but is supported and enumerated
independently.
- Fix a user-triggerable WARN that syzkaller found by setting the vCPU
in INIT_RECEIVED state (aka wait-for-SIPI), and then putting the vCPU
into VMX Root Mode (post-VMXON). Trying to detect every possible path
leading to architecturally forbidden states is hard and even risks
breaking userspace (if it goes from valid to valid state but passes
through invalid states), so just wait until KVM_RUN to detect that
the vCPU state isn't allowed.
- Add KVM_X86_DISABLE_EXITS_APERFMPERF to allow disabling interception of
APERF/MPERF reads, so that a "properly" configured VM can access
APERF/MPERF. This has many caveats (APERF/MPERF cannot be zeroed
on vCPU creation or saved/restored on suspend and resume, or preserved
over thread migration let alone VM migration) but can be useful whenever
you're interested in letting Linux guests see the effective physical CPU
frequency in /proc/cpuinfo.
- Reject KVM_SET_TSC_KHZ for vm file descriptors if vCPUs have been
created, as there's no known use case for changing the default
frequency for other VM types and it goes counter to the very reason
why the ioctl was added to the vm file descriptor. And also, there
would be no way to make it work for confidential VMs with a "secure"
TSC, so kill two birds with one stone.
- Dynamically allocation the shadow MMU's hashed page list, and defer
allocating the hashed list until it's actually needed (the TDP MMU
doesn't use the list).
- Extract many of KVM's helpers for accessing architectural local APIC
state to common x86 so that they can be shared by guest-side code for
Secure AVIC.
- Various cleanups and fixes.
x86 (Intel):
- Preserve the host's DEBUGCTL.FREEZE_IN_SMM when running the guest.
Failure to honor FREEZE_IN_SMM can leak host state into guests.
- Explicitly check vmcs12.GUEST_DEBUGCTL on nested VM-Enter to prevent
L1 from running L2 with features that KVM doesn't support, e.g. BTF.
x86 (AMD):
- WARN and reject loading kvm-amd.ko instead of panicking the kernel if the
nested SVM MSRPM offsets tracker can't handle an MSR (which is pretty
much a static condition and therefore should never happen, but still).
- Fix a variety of flaws and bugs in the AVIC device posted IRQ code.
- Inhibit AVIC if a vCPU's ID is too big (relative to what hardware
supports) instead of rejecting vCPU creation.
- Extend enable_ipiv module param support to SVM, by simply leaving
IsRunning clear in the vCPU's physical ID table entry.
- Disable IPI virtualization, via enable_ipiv, if the CPU is affected by
erratum #1235, to allow (safely) enabling AVIC on such CPUs.
- Request GA Log interrupts if and only if the target vCPU is blocking,
i.e. only if KVM needs a notification in order to wake the vCPU.
- Intercept SPEC_CTRL on AMD if the MSR shouldn't exist according to the
vCPU's CPUID model.
- Accept any SNP policy that is accepted by the firmware with respect to
SMT and single-socket restrictions. An incompatible policy doesn't put
the kernel at risk in any way, so there's no reason for KVM to care.
- Drop a superfluous WBINVD (on all CPUs!) when destroying a VM and
use WBNOINVD instead of WBINVD when possible for SEV cache maintenance.
- When reclaiming memory from an SEV guest, only do cache flushes on CPUs
that have ever run a vCPU for the guest, i.e. don't flush the caches for
CPUs that can't possibly have cache lines with dirty, encrypted data.
Generic:
- Rework irqbypass to track/match producers and consumers via an xarray
instead of a linked list. Using a linked list leads to O(n^2) insertion
times, which is hugely problematic for use cases that create large
numbers of VMs. Such use cases typically don't actually use irqbypass,
but eliminating the pointless registration is a future problem to
solve as it likely requires new uAPI.
- Track irqbypass's "token" as "struct eventfd_ctx *" instead of a "void *",
to avoid making a simple concept unnecessarily difficult to understand.
- Decouple device posted IRQs from VFIO device assignment, as binding a VM
to a VFIO group is not a requirement for enabling device posted IRQs.
- Clean up and document/comment the irqfd assignment code.
- Disallow binding multiple irqfds to an eventfd with a priority waiter,
i.e. ensure an eventfd is bound to at most one irqfd through the entire
host, and add a selftest to verify eventfd:irqfd bindings are globally
unique.
- Add a tracepoint for KVM_SET_MEMORY_ATTRIBUTES to help debug issues
related to private <=> shared memory conversions.
- Drop guest_memfd's .getattr() implementation as the VFS layer will call
generic_fillattr() if inode_operations.getattr is NULL.
- Fix issues with dirty ring harvesting where KVM doesn't bound the
processing of entries in any way, which allows userspace to keep KVM
in a tight loop indefinitely.
- Kill off kvm_arch_{start,end}_assignment() and x86's associated tracking,
now that KVM no longer uses assigned_device_count as a heuristic for
either irqbypass usage or MDS mitigation.
Selftests:
- Fix a comment typo.
- Verify KVM is loaded when getting any KVM module param so that attempting
to run a selftest without kvm.ko loaded results in a SKIP message about
KVM not being loaded/enabled (versus some random parameter not existing).
- Skip tests that hit EACCES when attempting to access a file, and rpint
a "Root required?" help message. In most cases, the test just needs to
be run with elevated permissions.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"ARM:
- Host driver for GICv5, the next generation interrupt controller for
arm64, including support for interrupt routing, MSIs, interrupt
translation and wired interrupts
- Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on
GICv5 hardware, leveraging the legacy VGIC interface
- Userspace control of the 'nASSGIcap' GICv3 feature, allowing
userspace to disable support for SGIs w/o an active state on
hardware that previously advertised it unconditionally
- Map supporting endpoints with cacheable memory attributes on
systems with FEAT_S2FWB and DIC where KVM no longer needs to
perform cache maintenance on the address range
- Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the
guest hypervisor to inject external aborts into an L2 VM and take
traps of masked external aborts to the hypervisor
- Convert more system register sanitization to the config-driven
implementation
- Fixes to the visibility of EL2 registers, namely making VGICv3
system registers accessible through the VGIC device instead of the
ONE_REG vCPU ioctls
- Various cleanups and minor fixes
LoongArch:
- Add stat information for in-kernel irqchip
- Add tracepoints for CPUCFG and CSR emulation exits
- Enhance in-kernel irqchip emulation
- Various cleanups
RISC-V:
- Enable ring-based dirty memory tracking
- Improve perf kvm stat to report interrupt events
- Delegate illegal instruction trap to VS-mode
- MMU improvements related to upcoming nested virtualization
s390x
- Fixes
x86:
- Add CONFIG_KVM_IOAPIC for x86 to allow disabling support for I/O
APIC, PIC, and PIT emulation at compile time
- Share device posted IRQ code between SVM and VMX and harden it
against bugs and runtime errors
- Use vcpu_idx, not vcpu_id, for GA log tag/metadata, to make lookups
O(1) instead of O(n)
- For MMIO stale data mitigation, track whether or not a vCPU has
access to (host) MMIO based on whether the page tables have MMIO
pfns mapped; using VFIO is prone to false negatives
- Rework the MSR interception code so that the SVM and VMX APIs are
more or less identical
- Recalculate all MSR intercepts from scratch on MSR filter changes,
instead of maintaining shadow bitmaps
- Advertise support for LKGS (Load Kernel GS base), a new instruction
that's loosely related to FRED, but is supported and enumerated
independently
- Fix a user-triggerable WARN that syzkaller found by setting the
vCPU in INIT_RECEIVED state (aka wait-for-SIPI), and then putting
the vCPU into VMX Root Mode (post-VMXON). Trying to detect every
possible path leading to architecturally forbidden states is hard
and even risks breaking userspace (if it goes from valid to valid
state but passes through invalid states), so just wait until
KVM_RUN to detect that the vCPU state isn't allowed
- Add KVM_X86_DISABLE_EXITS_APERFMPERF to allow disabling
interception of APERF/MPERF reads, so that a "properly" configured
VM can access APERF/MPERF. This has many caveats (APERF/MPERF
cannot be zeroed on vCPU creation or saved/restored on suspend and
resume, or preserved over thread migration let alone VM migration)
but can be useful whenever you're interested in letting Linux
guests see the effective physical CPU frequency in /proc/cpuinfo
- Reject KVM_SET_TSC_KHZ for vm file descriptors if vCPUs have been
created, as there's no known use case for changing the default
frequency for other VM types and it goes counter to the very reason
why the ioctl was added to the vm file descriptor. And also, there
would be no way to make it work for confidential VMs with a
"secure" TSC, so kill two birds with one stone
- Dynamically allocation the shadow MMU's hashed page list, and defer
allocating the hashed list until it's actually needed (the TDP MMU
doesn't use the list)
- Extract many of KVM's helpers for accessing architectural local
APIC state to common x86 so that they can be shared by guest-side
code for Secure AVIC
- Various cleanups and fixes
x86 (Intel):
- Preserve the host's DEBUGCTL.FREEZE_IN_SMM when running the guest.
Failure to honor FREEZE_IN_SMM can leak host state into guests
- Explicitly check vmcs12.GUEST_DEBUGCTL on nested VM-Enter to
prevent L1 from running L2 with features that KVM doesn't support,
e.g. BTF
x86 (AMD):
- WARN and reject loading kvm-amd.ko instead of panicking the kernel
if the nested SVM MSRPM offsets tracker can't handle an MSR (which
is pretty much a static condition and therefore should never
happen, but still)
- Fix a variety of flaws and bugs in the AVIC device posted IRQ code
- Inhibit AVIC if a vCPU's ID is too big (relative to what hardware
supports) instead of rejecting vCPU creation
- Extend enable_ipiv module param support to SVM, by simply leaving
IsRunning clear in the vCPU's physical ID table entry
- Disable IPI virtualization, via enable_ipiv, if the CPU is affected
by erratum #1235, to allow (safely) enabling AVIC on such CPUs
- Request GA Log interrupts if and only if the target vCPU is
blocking, i.e. only if KVM needs a notification in order to wake
the vCPU
- Intercept SPEC_CTRL on AMD if the MSR shouldn't exist according to
the vCPU's CPUID model
- Accept any SNP policy that is accepted by the firmware with respect
to SMT and single-socket restrictions. An incompatible policy
doesn't put the kernel at risk in any way, so there's no reason for
KVM to care
- Drop a superfluous WBINVD (on all CPUs!) when destroying a VM and
use WBNOINVD instead of WBINVD when possible for SEV cache
maintenance
- When reclaiming memory from an SEV guest, only do cache flushes on
CPUs that have ever run a vCPU for the guest, i.e. don't flush the
caches for CPUs that can't possibly have cache lines with dirty,
encrypted data
Generic:
- Rework irqbypass to track/match producers and consumers via an
xarray instead of a linked list. Using a linked list leads to
O(n^2) insertion times, which is hugely problematic for use cases
that create large numbers of VMs. Such use cases typically don't
actually use irqbypass, but eliminating the pointless registration
is a future problem to solve as it likely requires new uAPI
- Track irqbypass's "token" as "struct eventfd_ctx *" instead of a
"void *", to avoid making a simple concept unnecessarily difficult
to understand
- Decouple device posted IRQs from VFIO device assignment, as binding
a VM to a VFIO group is not a requirement for enabling device
posted IRQs
- Clean up and document/comment the irqfd assignment code
- Disallow binding multiple irqfds to an eventfd with a priority
waiter, i.e. ensure an eventfd is bound to at most one irqfd
through the entire host, and add a selftest to verify eventfd:irqfd
bindings are globally unique
- Add a tracepoint for KVM_SET_MEMORY_ATTRIBUTES to help debug issues
related to private <=> shared memory conversions
- Drop guest_memfd's .getattr() implementation as the VFS layer will
call generic_fillattr() if inode_operations.getattr is NULL
- Fix issues with dirty ring harvesting where KVM doesn't bound the
processing of entries in any way, which allows userspace to keep
KVM in a tight loop indefinitely
- Kill off kvm_arch_{start,end}_assignment() and x86's associated
tracking, now that KVM no longer uses assigned_device_count as a
heuristic for either irqbypass usage or MDS mitigation
Selftests:
- Fix a comment typo
- Verify KVM is loaded when getting any KVM module param so that
attempting to run a selftest without kvm.ko loaded results in a
SKIP message about KVM not being loaded/enabled (versus some random
parameter not existing)
- Skip tests that hit EACCES when attempting to access a file, and
print a "Root required?" help message. In most cases, the test just
needs to be run with elevated permissions"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (340 commits)
Documentation: KVM: Use unordered list for pre-init VGIC registers
RISC-V: KVM: Avoid re-acquiring memslot in kvm_riscv_gstage_map()
RISC-V: KVM: Use find_vma_intersection() to search for intersecting VMAs
RISC-V: perf/kvm: Add reporting of interrupt events
RISC-V: KVM: Enable ring-based dirty memory tracking
RISC-V: KVM: Fix inclusion of Smnpm in the guest ISA bitmap
RISC-V: KVM: Delegate illegal instruction fault to VS mode
RISC-V: KVM: Pass VMID as parameter to kvm_riscv_hfence_xyz() APIs
RISC-V: KVM: Factor-out g-stage page table management
RISC-V: KVM: Add vmid field to struct kvm_riscv_hfence
RISC-V: KVM: Introduce struct kvm_gstage_mapping
RISC-V: KVM: Factor-out MMU related declarations into separate headers
RISC-V: KVM: Use ncsr_xyz() in kvm_riscv_vcpu_trap_redirect()
RISC-V: KVM: Implement kvm_arch_flush_remote_tlbs_range()
RISC-V: KVM: Don't flush TLB when PTE is unchanged
RISC-V: KVM: Replace KVM_REQ_HFENCE_GVMA_VMID_ALL with KVM_REQ_TLB_FLUSH
RISC-V: KVM: Rename and move kvm_riscv_local_tlb_sanitize()
RISC-V: KVM: Drop the return value of kvm_riscv_vcpu_aia_init()
RISC-V: KVM: Check kvm_riscv_vcpu_alloc_vector_context() return value
KVM: arm64: selftests: Add FEAT_RAS EL2 registers to get-reg-list
...
The 'kernel lock contention analysis test' requires reliable triggering
of lock contention. On some systems, previous benchmark calls failed to
generate sufficient contention due to low system activity or resource
limits.
This patch adds the -p (pipe) option to all calls of perf bench sched
messaging, ensuring consistent lock contention without relying on
socket-based communication.
Suggested-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Jan Polensky <japo@linux.ibm.com>
Link: https://lore.kernel.org/r/20250725170801.3176678-1-japo@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
As noticed while building for Fedora 43:
GEN /tmp/build/perf/python/perf.cpython-314-x86_64-linux-gnu.so
/git/perf-6.16.0-rc3/tools/perf/util/python.c: In function ‘get_tracepoint_field’:
/git/perf-6.16.0-rc3/tools/perf/util/python.c:340:9: error: ‘_PyUnicode_AsString’ is deprecated [-Werror=deprecated-declarations]
340 | const char *str = _PyUnicode_AsString(PyObject_Str(attr_name));
| ^~~~~
In file included from /usr/include/python3.14/unicodeobject.h:1022,
from /usr/include/python3.14/Python.h:89,
from /git/perf-6.16.0-rc3/tools/perf/util/python.c:2:
/usr/include/python3.14/cpython/unicodeobject.h:648:1: note: declared here
648 | _PyUnicode_AsString(PyObject *unicode)
| ^~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
error: command '/usr/bin/gcc' failed with exit code 1
Use PyUnicode_AsUTF8() instead and also check if PyObject_Str() fails
before doing so.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/aIofXNK8QLtLIaI3@x1
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Avoid printing tracepoint, legacy and software events when listing for
the pmu option. Add the PMU type to the print_event callbacks to ease
detection.
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250725185202.68671-8-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Now that the tp_pmu can iterate and describe events remove the custom
tracepoint printing logic, this avoids perf list showing the
tracepoint events twice.
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250725185202.68671-7-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Start the creation of a tracepoint PMU abstraction. Tracepoint events
don't follow the regular sysfs perf conventions. Eventually the new
PMU abstraction will bridge the gap so tracepoint events look more
like regular perf ones.
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250725185202.68671-5-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Remove the hard coded encodings from parse-events. This has the
consequence that software events are matched using the sysfs/json
priority, will be case insensitive and will be wildcarded across PMUs.
As there were software and hardware types in the parsing code, the
removal means software vs hardware logic can be removed and hardware
assumed.
Now the perf json provides detailed descriptions of software events,
remove the previous listing support that didn't contain event
descriptions. When globbing is required for the "sw" option in perf
list, use string PMU globbing as was done previously for the tool PMU.
The output of `perf list sw` command changed like this.
Before:
List of pre-defined events (to be used in -e or -M):
alignment-faults [Software event]
bpf-output [Software event]
cgroup-switches [Software event]
context-switches OR cs [Software event]
cpu-clock [Software event]
cpu-migrations OR migrations [Software event]
dummy [Software event]
emulation-faults [Software event]
major-faults [Software event]
minor-faults [Software event]
page-faults OR faults [Software event]
task-clock [Software event]
After:
List of pre-defined events (to be used in -e or -M):
software:
alignment-faults
[Number of kernel handled memory alignment faults. Unit: software]
bpf-output
[An event used by BPF programs to write to the perf ring buffer. Unit: software]
cgroup-switches
[Number of context switches to a task in a different cgroup. Unit: software]
context-switches
[Number of context switches [This event is an alias of cs]. Unit: software]
cpu-clock
[Per-CPU high-resolution timer based event. Unit: software]
cpu-migrations
[Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
cs
[Number of context switches [This event is an alias of context-switches]. Unit: software]
dummy
[A placeholder event that doesn't count anything. Unit: software]
...
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250725185202.68671-4-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Add json for software events so that in perf list the events can have
a description. Common json exists for the tool PMU but it has no
sysfs equivalent. Modify the map_for_pmu code to return the common map
(rather than an architecture specific one) when a PMU with a common
name is being looked for, this allows the events to be found.
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250725185202.68671-3-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The libtraceevent has been removed from the source tree, and .gitignore
needs to be updated as well.
Fixes: 4171925aa9 ("tools lib traceevent: Remove libtraceevent")
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250726111532.8031-1-cp0613@linux.alibaba.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The previous commit that introduced this test overlooked a behavior of
"perf test list", causing it to print "SPDX-License-Identifier: GPL-2.0"
as a description for that test. This reorders the comments to fix that
issue.
Fixes: edf2cadf01 ("perf test: add test for BPF metadata collection")
Signed-off-by: Blake Jones <blakejones@google.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250726004023.3466563-1-blakejones@google.com
[ update the commit message a little bit ]
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Previously arch_support_sort_key and arch_perf_header_entry used a
weak symbol to compile as appropriate for x86 and powerpc. A
limitation to this is that the handling of a data file could vary in
cross-platform development. Change to using the perf_env of the
current session to determine the architecture kind and set the sort
key and header entries as appropriate.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-23-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
test__x86_sample_parsing is identical to test__sample_parsing except
it explicitly tested PERF_SAMPLE_WEIGHT_STRUCT. Now the parsing code
is common move the PERF_SAMPLE_WEIGHT_STRUCT to the common sample
parsing test and remove the x86 version.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-22-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
By definition arch sample parsing and synthesis will inhibit certain
kinds of cross-platform record then analysis (report, script,
etc.). Remove arch_perf_parse_sample_weight and
arch_perf_synthesize_sample_weight replacing with a common
implementation. Combine perf_sample p_stage_cyc and retire_lat as
weight3 to capture the differing uses regardless of compiled for
architecture.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-21-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The global perf_env was used for the host, but if a perf_env wasn't
easy to come by it was used in a lot of places where potentially
recorded and host data could be confused. Remove the global variable
as now the majority of accesses retrieve the perf_env for the host
from the session.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-20-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
There is no session in perf trace unless in replay mode, so in host
mode no session can be associated with the evlist. If the evsel__env
call fails resort to the host_env that's part of the trace. Remove
errno_to_name as it becomes a called once 1-line function once the
argument is turned into a perf_env, just call perf_env__arch_strerrno
directly.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-19-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
auxtrace_mmap__read and auxtrace_mmap__read_snapshot end up calling
`evsel__env(NULL)` which returns the global perf_env variable for the
host. Their only call is in perf record. Rather than use the global
variable pass through the perf_env for `perf record`.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-18-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
When creating a machine for the host explicitly pass in a scoped
perf_env. This removes a use of the global perf_env.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-17-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The benchmark doesn't use a data file and so the header perf_env isn't
used. Stack allocate a host perf_env for use to avoid the use of the
global perf_env.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-16-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The use of the global host perf_env variable is potentially
inconsistent within the code. Switch perf top to using a locally
scoped variable that is generally accessed through the session.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-15-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
When creating a perf_session the host perf_env may or may not want to
be used. For example, `perf top` uses a host perf_env while `perf
inject` does not. Add a host_env argument to perf_session__new so that
sessions requiring a host perf_env can pass it in. Currently if none
is specified the global perf_env variable is used, but this will
change in later patches.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-14-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The perf_env global variable holds the host perf_env data but its use
is hit and miss. Switch to using local perf_env variables and ensure
scoped perf_env__init and perf_env__exit. This loses command line
setting of the perf_env, but this doesn't matter for tests. So the
perf_env is fully initialized, clear it with memset in perf_env__init.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-13-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Always use the perf_env from the feat_fd's perf_header. Cache the
value on entry to a function in `env` and use `env->` consistently in
the code. Ensure the header is initialized for use in
perf_session__do_write_header.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-12-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The session holds a perf_env pointer env. In UI code container_of is
used to turn the env to a session, but this assumes the session
header's env is in use. Rather than a dubious container_of, hold the
session in the evlist and derive the env from the session with
evsel__env, perf_session__env, etc.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-11-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The perf_env from the header in the session is frequently accessed,
add an accessor function rather than access directly. Cache the value
to avoid repeated calls. No behavioral change.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-10-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Support for build IDs in mmap2 perf events has been present since
Linux v5.12:
https://lore.kernel.org/lkml/20210219194619.1780437-1-acme@kernel.org/
Build ID mmap events don't avoid the need to inject build IDs for DSO
touched by samples as the build ID cache is populated by perf
record. They can avoid some cases of symbol mis-resolution caused by
the file system changing from when a sample occurred and when the DSO
is sought.
Unlike the --buildid-mmap option, this chnage doesn't disable the
build ID cache but it does disable the processing of samples looking
for DSOs to inject build IDs for. To disable the build ID cache the -B
(--no-buildid) option should be used.
Making this option the default was raised on the list in:
https://lore.kernel.org/linux-perf-users/CAP-5=fXP7jN_QrGUcd55_QH5J-Y-FCaJ6=NaHVtyx0oyNh8_-Q@mail.gmail.com/
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-9-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The DSO being generated was being accessed through a thread's maps,
this is unnecessary as the dso can just be directly found. This avoids
problems with passing a NULL evsel which may be inspected to determine
properties of a callchain when using the buildid DSO marking code.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-8-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The dso_id previously contained the major, minor, inode and inode
generation information from a mmap2 event - the inode generation would
be zero when reading from /proc/pid/maps. The build_id was in the
dso. With build ID mmap2 events these fields wouldn't be initialized
which would largely mean the special empty case where any dso would
match for equality. This isn't desirable as if a dso is replaced we
want the comparison to yield a difference.
To support detecting the difference between DSOs based on build_id,
move the build_id out of the DSO and into the dso_id. The dso_id is
also stored in the DSO so nothing is lost. Capture in the dso_id what
parts have been initialized and rename dso_id__inject to
dso_id__improve_id so that it is clear the dso_id is being improved
upon with additional information. With the build_id in the dso_id, use
memcmp to compare for equality.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-7-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
If a build ID is read then not all code paths may ensure it is empty
before use. Initialize the build_id to be zero-ed unless there is
clear initialization such as a call to build_id__init.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-6-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Previously only the sample IP's map DSO would be marked hit for the
purposes of populating the build ID cache. Walk the call chain to mark
all IPs and DSOs.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-5-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Pass in a size argument rather than implying all build id strings must
be SBUILD_ID_SIZE.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-4-irogers@google.com
[ fixed some build errors ]
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Warning when the build_id data would be overflowed would lead to
memory corruption, switch to truncation.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-3-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Later clean up of the dso_id to include a build_id will suffer from
alignment and size issues. The size can only hold up to a value of
BUILD_ID_SIZE (20) and the mmap2 event uses a byte for the value.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Thresholds can increase the number of counters a metric needs. The NMI
watchdog can take away a counter (hopefully the buddy watchdog will
become the default and this will no longer be true). Add a new
constraint for the case that a metric and its thresholds would fit in
counters but only if the NMI watchdog isn't enabled. Either the
threshold or the NMI watchdog should be disabled to make the metric
fit. Wire this up into the metric__group_events logic.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250719030517.1990983-16-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Topdown metric events require grouping with a slots event. In perf
metrics this is currently achieved by metrics adding an unnecessary
"0 * tma_info_thread_slots". New TMA metrics trigger optimizations of
the metric expression that removes the event and breaks the metric due
to the missing but required event. Add a pass immediately before
sorting and fixing parsed events, that insert a slots event if one is
missing. Update test expectations to match this.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250719030517.1990983-15-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The string comparisons were overly broad and could fire for the
incorrect PMU and events. Switch to using the config in the attribute
then add a perf test to confirm the attribute config values match
those of parsed events of that name and don't match others. This
exposed matches for slots events that shouldn't have matched as the
slots fixed counter event, such as topdown.slots_p.
Fixes: fbc798316b ("perf x86/topdown: Refine helper arch_is_topdown_metrics()")
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250719030517.1990983-14-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Counting events system-wide with a specified CPU prior to this change
worked:
```
$ perf stat -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' -a sleep 1
Performance counter stats for 'system wide':
59,393,419,099 msr/tsc/
33,927,965,927 msr/tsc,cpu=cpu_core/
25,465,608,044 msr/tsc,cpu=cpu_atom/
```
However, when counting with process the counts became system wide:
```
$ perf stat -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' perf test -F 10
10.1: Basic parsing test : Ok
10.2: Parsing without PMU name : Ok
10.3: Parsing with PMU name : Ok
Performance counter stats for 'perf test -F 10':
59,233,549 msr/tsc/
59,227,556 msr/tsc,cpu=cpu_core/
59,224,053 msr/tsc,cpu=cpu_atom/
```
Make the handling of CPU maps with event parsing clearer. When an
event is parsed creating an evsel the cpus should be either the PMU's
cpumask or user specified CPUs.
Update perf_evlist__propagate_maps so that it doesn't clobber the user
specified CPUs. Try to make the behavior clearer, firstly fix up
missing cpumasks. Next, perform sanity checks and adjustments from the
global evlist CPU requests and for the PMU including simplifying to
the "any CPU"(-1) value. Finally remove the event if the cpumask is
empty.
So that events are opened with a CPU and a thread change stat's
create_perf_stat_counter to give both.
With the change things are fixed:
```
$ perf stat --no-scale -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' perf test -F 10
10.1: Basic parsing test : Ok
10.2: Parsing without PMU name : Ok
10.3: Parsing with PMU name : Ok
Performance counter stats for 'perf test -F 10':
63,704,975 msr/tsc/
47,060,704 msr/tsc,cpu=cpu_core/ (4.62%)
16,640,591 msr/tsc,cpu=cpu_atom/ (2.18%)
```
However, note the "--no-scale" option is used. This is necessary as
the running time for the event on the counter isn't the same as the
enabled time because the thread doesn't necessarily run on the CPUs
specified for the counter. All counter values are scaled with:
scaled_value = value * time_enabled / time_running
and so without --no-scale the scaled_value becomes very large. This
problem already exists on hybrid systems for the same reason. Here are
2 runs of the same code with an instructions event that counts the
same on both types of core, there is no real multiplexing happening on
the event:
```
$ perf stat -e instructions perf test -F 10
...
Performance counter stats for 'perf test -F 10':
87,896,447 cpu_atom/instructions/ (14.37%)
98,171,964 cpu_core/instructions/ (85.63%)
...
$ perf stat --no-scale -e instructions perf test -F 10
...
Performance counter stats for 'perf test -F 10':
13,069,890 cpu_atom/instructions/ (19.32%)
83,460,274 cpu_core/instructions/ (80.68%)
...
```
The scaling has inflated per-PMU instruction counts and the overall
count by 2x.
To fix this the kernel needs changing when a task+CPU event (or just
task event on hybrid) is scheduled out. A fix could be that the state
isn't inactive but off for such events, so that time_enabled counts
don't accumulate on them.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250719030517.1990983-13-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Add evsel__open_per_cpu_and_thread that combines the operation of
evsel__open_per_cpu and evsel__open_per_thread so that an event
without the "any" cpumask can be opened with its cpumask and with
threads it specifies. Change the implementation of evsel__open_per_cpu
and evsel__open_per_thread to use evsel__open_per_cpu_and_thread to
make the implementation of those functions clearer.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-12-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Rename cpu_list to user_cpus. If a PMU isn't given, find it early from
the perf_event_attr. Make the pmu_cpus more explicitly a copy from the
PMU (except when user_cpus are given). Derive the cpus from pmu_cpus
and user_cpus as appropriate. Handle strdup errors on name and
metric_id.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-11-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Allow a PMU to be found by a perf_event_attr, useful when creating
evsels.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-10-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Avoid the duplicated code and better enable perf_evsel to change.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-9-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
own_cpus is generally the cpumask from the PMU. Rename to pmu_cpus to
try to make this clearer. Variable rename with no other changes.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-7-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
For hybrid metrics it is useful to know the number of p-core or e-core
CPUs. If a cpumask is specified for the num_cpus or num_cpus_online
tool events, compute the value relative to the given mask rather than
for the full system.
```
$ sudo /tmp/perf/perf stat -e 'tool/num_cpus/,tool/num_cpus,cpu=cpu_core/,
tool/num_cpus,cpu=cpu_atom/,tool/num_cpus_online/,tool/num_cpus_online,
cpu=cpu_core/,tool/num_cpus_online,cpu=cpu_atom/' true
Performance counter stats for 'true':
28 tool/num_cpus/
16 tool/num_cpus,cpu=cpu_core/
12 tool/num_cpus,cpu=cpu_atom/
28 tool/num_cpus_online/
16 tool/num_cpus_online,cpu=cpu_core/
12 tool/num_cpus_online,cpu=cpu_atom/
0.000767205 seconds time elapsed
0.000938000 seconds user
0.000000000 seconds sys
```
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-6-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
On hybrid systems, events like msr/tsc/ will aggregate counts across
all CPUs. Often metrics only want a value like msr/tsc/ for the cores
on which the metric is being computed. Listing each CPU with terms
cpu=0,cpu=1.. is laborious and would need to be encoded for all
variations of a CPU model.
Allow the cpumask from a PMU to be an argument to the cpu term. For
example in the following the cpumask of the cstate_pkg PMU selects the
CPUs to count msr/tsc/ counter upon:
```
$ cat /sys/bus/event_source/devices/cstate_pkg/cpumask
0
$ perf stat -A -e 'msr/tsc,cpu=cstate_pkg/' -a sleep 0.1
Performance counter stats for 'system wide':
CPU0 252,621,253 msr/tsc,cpu=cstate_pkg/
0.101184092 seconds time elapsed
```
As the cpu term is now also allowed to be a string, allow it to encode
a range of CPUs (a list can't be supported as ',' is already a special
token).
The "event qualifiers" section of the `perf list` man page is updated
to detail the additional behavior. The man page formatting is tidied
up in this section, as it was incorrectly appearing within the
"parameterized events" section.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250719030517.1990983-5-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
As evsels may have additional CPU terms, the user_requested_cpus may
not reflect all the CPUs requested. Use evlist->all_cpus to size the
array as that reflects all the CPUs potentially needed by the evlist.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-4-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
CPUs may be created and passed to perf_stat__get_aggr (via
config->aggr_get_id), such as in the stat display
should_skip_zero_counter. There may be no such aggr_id, for example,
if running with a thread. Add a missing bound check and just create
IDs for these cases.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-3-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Factor requested CPU warning out of evlist and into evsel. At the end
of adding an event, perform the warning check. To avoid repeatedly
testing if the cpu_list is empty, add a local variable.
```
$ perf stat -e cpu_atom/cycles,cpu=1/ -a true
WARNING: A requested CPU in '1' is not supported by PMU 'cpu_atom' (CPUs 16-27) for event 'cpu_atom/cycles/'
Performance counter stats for 'system wide':
<not supported> cpu_atom/cycles/
0.000781511 seconds time elapsed
```
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
