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linux/arch/x86/kernel
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Anton Blanchard 339ce1a4dc perf: Fix inconsistency between IP and callchain sampling 
When running perf across all cpus with backtracing (-a -g), sometimes we
get samples without associated backtraces:

    23.44%         init  [kernel]                     [k] restore
    11.46%         init                       eeba0c  [k] 0x00000000eeba0c
     6.77%      swapper  [kernel]                     [k] .perf_ctx_adjust_freq
     5.73%         init  [kernel]                     [k] .__trace_hcall_entry
     4.69%         perf  libc-2.9.so                  [.] 0x0000000006bb8c
                       |
                       |--11.11%-- 0xfffa941bbbc

It turns out the backtrace code has a check for the idle task and the IP
sampling does not. This creates problems when profiling an interrupt
heavy workload (in my case 10Gbit ethernet) since we get no backtraces
for interrupts received while idle (ie most of the workload).

Right now x86 and sh check that current is not NULL, which should never
happen so remove that too.

Idle task's exclusion must be performed from the core code, on top
of perf_event_attr:exclude_idle.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
LKML-Reference: <20100118054707.GT12666@kryten>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-01-28 14:31:20 +01:00
..
acpi ACPI: introduce kernel parameter acpi_sleep=sci_force_enable 2009-12-30 18:32:01 -05:00
apic Revert "x86, apic: Use logical flat on intel with <= 8 logical cpus" 2010-01-11 16:47:57 -08:00
cpu perf: Fix inconsistency between IP and callchain sampling 2010-01-28 14:31:20 +01:00
.gitignore
alternative.c
amd_iommu.c iommu-helper: use bitmap library 2009-12-16 07:20:18 -08:00
amd_iommu_init.c x86/amd-iommu: Fix initialization failure panic 2009-12-21 15:51:23 +01:00
aperture_64.c x86: Gart: fix breakage due to IOMMU initialization cleanup 2009-12-14 08:57:40 +01:00
apm_32.c
asm-offsets.c
asm-offsets_32.c
asm-offsets_64.c
audit_64.c
bios_uv.c x86: uv: update XPC to handle updated BIOS interface 2009-12-16 07:20:14 -08:00
bootflag.c
check.c
cpuid.c x86, msr/cpuid: Register enough minors for the MSR and CPUID drivers 2009-12-15 15:13:07 -08:00
crash.c
crash_dump_32.c
crash_dump_64.c
doublefault_32.c
ds.c
ds_selftest.c
ds_selftest.h
dumpstack.c perf: Stop stack frame walking off kernel addresses boundaries 2010-01-13 09:32:54 +01:00
dumpstack.h perf events, x86/stacktrace: Make stack walking optional 2009-12-17 09:56:19 +01:00
dumpstack_32.c perf: Drop useless check for ignored frame 2010-01-13 10:09:08 +01:00
dumpstack_64.c perf: Drop useless check for ignored frame 2010-01-13 10:09:08 +01:00
e820.c x86: Fix size for ex trampoline with 32bit 2010-01-04 13:20:11 -08:00
early-quirks.c
early_printk.c
efi.c
efi_32.c
efi_64.c
efi_stub_32.S
efi_stub_64.S
entry_32.S x86, 32-bit: Use same regs as 64-bit for kernel_thread_helper 2009-12-10 15:55:36 -08:00
entry_64.S Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-16 12:02:37 -08:00
ftrace.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:27:33 -08:00
head.c
head32.c x86: Use find_e820() instead of hard coded trampoline address 2009-12-11 09:28:22 +01:00
head64.c x86: Use find_e820() instead of hard coded trampoline address 2009-12-11 09:28:22 +01:00
head_32.S
head_64.S Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:27:33 -08:00
hpet.c x86: hpet: Make WARN_ON understandable 2009-11-27 20:37:41 +01:00
hw_breakpoint.c hw-breakpoints: Use overflow handler instead of the event callback 2009-12-06 08:27:18 +01:00
i386_ksyms_32.c
i387.c
i8237.c
i8253.c
i8259.c
init_task.c
io_delay.c
ioport.c x86-64, paravirt: Call set_iopl_mask() on 64 bits 2009-12-09 16:54:08 -08:00
irq.c genirq: Convert irq_desc.lock to raw_spinlock 2009-12-14 23:55:33 +01:00
irq_32.c
irq_64.c
irqinit.c
k8.c
kdebugfs.c
kgdb.c kgdb,x86: do not set kgdb_single_step on x86 2009-12-11 08:43:18 -06:00
kprobes.c Merge branch 'for-next' into for-linus 2009-12-07 18:36:35 +01:00
kvm.c
kvmclock.c
ldt.c
machine_kexec_32.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:27:33 -08:00
machine_kexec_64.c
Makefile cs5535: drop the Geode-specific MFGPT/GPIO code 2009-12-15 08:53:28 -08:00
mca_32.c
microcode_amd.c arch/x86/kernel/microcode*: Use pr_fmt() and remove duplicated KERN_ERR prefix 2009-12-09 08:25:57 +01:00
microcode_core.c Revert "x86, ucode-amd: Ensure ucode update on suspend/resume after CPU off/online cycle" 2009-12-23 15:04:53 -08:00
microcode_intel.c arch/x86/kernel/microcode*: Use pr_fmt() and remove duplicated KERN_ERR prefix 2009-12-09 08:25:57 +01:00
mmconf-fam10h_64.c
module.c
mpparse.c x86: Use find_e820() instead of hard coded trampoline address 2009-12-11 09:28:22 +01:00
mrst.c
msr.c x86, msr/cpuid: Register enough minors for the MSR and CPUID drivers 2009-12-15 15:13:07 -08:00
olpc.c cs5535: move VSA2 checks into linux/cs5535.h 2009-12-15 08:53:28 -08:00
paravirt-spinlocks.c locking: Convert __raw_spin* functions to arch_spin* 2009-12-14 23:55:32 +01:00
paravirt.c
paravirt_patch_32.c
paravirt_patch_64.c
pci-calgary_64.c iommu-helper: use bitmap library 2009-12-16 07:20:18 -08:00
pci-dma.c x86: Split swiotlb initialization into two stages 2009-12-15 13:01:57 +01:00
pci-gart_64.c iommu-helper: use bitmap library 2009-12-16 07:20:18 -08:00
pci-nommu.c
pci-swiotlb.c x86: Split swiotlb initialization into two stages 2009-12-15 13:01:57 +01:00
pcspeaker.c
pmtimer_64.c
probe_roms_32.c
process.c x86: Use KERN_DEFAULT log-level in __show_regs() 2009-12-28 09:40:21 +01:00
process_32.c x86: Use KERN_DEFAULT log-level in __show_regs() 2009-12-28 09:40:21 +01:00
process_64.c x86: Use KERN_DEFAULT log-level in __show_regs() 2009-12-28 09:40:21 +01:00
ptrace.c x86/ptrace: Remove unused regs_get_argument_nth API 2010-01-13 10:09:12 +01:00
pvclock.c
quirks.c
reboot.c Merge branch 'linus' into x86/urgent 2009-12-07 13:14:18 +01:00
reboot_fixups_32.c cs5535: move the DIVIL MSR definition into linux/cs5535.h 2009-12-15 08:53:28 -08:00
relocate_kernel_32.S
relocate_kernel_64.S
rtc.c
scx200_32.c
setup.c x86: Use find_e820() instead of hard coded trampoline address 2009-12-11 09:28:22 +01:00
setup_percpu.c x86: setup_percpu.c: Use pr_<level> and add pr_fmt(fmt) 2009-12-10 08:57:50 +01:00
sfi.c
signal.c x86: Merge sys_sigaltstack 2009-12-09 16:28:59 -08:00
smp.c
smpboot.c x86: Limit the number of processor bootup messages 2009-12-11 15:16:00 -08:00
stacktrace.c perf events, x86/stacktrace: Make stack walking optional 2009-12-17 09:56:19 +01:00
step.c
sys_i386_32.c Unify sys_mmap* 2009-12-11 06:44:29 -05:00
sys_x86_64.c Unify sys_mmap* 2009-12-11 06:44:29 -05:00
syscall_64.c
syscall_table_32.S Unify sys_mmap* 2009-12-11 06:44:29 -05:00
tboot.c
tce_64.c
test_nx.c
test_rodata.c
time.c
tlb_uv.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:27:33 -08:00
tls.c
tls.h
topology.c
trampoline.c x86: Use find_e820() instead of hard coded trampoline address 2009-12-11 09:28:22 +01:00
trampoline_32.S
trampoline_64.S
traps.c
tsc.c x86: Reenable TSC sync check at boot, even with NONSTOP_TSC 2009-12-17 14:44:35 -08:00
tsc_sync.c locking: Convert __raw_spin* functions to arch_spin* 2009-12-14 23:55:32 +01:00
uv_irq.c x86, irq: Allow 0xff for /proc/irq/[n]/smp_affinity on an 8-cpu system 2009-12-17 22:03:06 -08:00
uv_sysfs.c
uv_time.c
verify_cpu_64.S
visws_quirks.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:27:33 -08:00
vm86_32.c x86, 32-bit: Convert sys_vm86 & sys_vm86old 2009-12-09 16:29:23 -08:00
vmi_32.c
vmiclock_32.c
vmlinux.lds.S x86: Regex support and known-movable symbols for relocs, fix _end 2009-12-14 13:55:20 -08:00
vsmp_64.c
vsyscall_64.c Merge branch 'timers-for-linus-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 19:28:09 -08:00
x86_init.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:27:33 -08:00
x8664_ksyms_64.c Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-16 12:02:37 -08:00
xsave.c