linux/tools
Leo Yan 791ce9c48c perf test: Avoid infinite loop for task exit case
When executing the task exit testing case, perf gets stuck in an endless
loop this case and doesn't return back on Arm64 Juno board.

After digging into this issue, since Juno board has Arm's big.LITTLE
CPUs, thus the PMUs are not compatible between the big CPUs and little
CPUs.  This leads to a PMU event that cannot be enabled properly when
the traced task is migrated from one variant's CPU to another variant.
Finally, the test case runs into infinite loop for cannot read out any
event data after return from polling.

Eventually, we need to work out formal solution to allow PMU events can
be freely migrated from one CPU variant to another, but this is a
difficult task and a different topic.  This patch tries to fix the Perf
test case to avoid infinite loop, when the testing detects 1000 times
retrying for reading empty events, it will directly bail out and return
failure.  This allows the Perf tool can continue its other test cases.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/20191011091942.29841-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-10-15 08:36:22 -03:00
..
accounting
arch tools arch x86: Grab a copy of the file containing the MSR numbers 2019-10-07 12:22:18 -03:00
bpf Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2019-09-06 16:49:17 +02:00
build tools build: Add capability-related feature detection 2019-08-12 17:14:14 -03:00
cgroup iocost_monitor: Report debt 2019-09-10 12:31:39 -06:00
debugging
firewire
firmware
gpio
hv - First round of vmbus hibernation support from Dexuan Cui. 2019-09-24 12:36:31 -07:00
iio tools: iio: add .gitignore 2019-08-18 20:45:57 +01:00
include tools headers kvm: Sync kvm headers with the kernel sources 2019-09-30 17:29:30 -03:00
io_uring
kvm/kvm_stat
laptop
leds
lib perf/urgent fixes: 2019-10-07 15:15:24 +02:00
memory-model tools/memory-model: Update the informal documentation 2019-08-09 10:28:57 -07:00
nfsd
objtool KVM: x86: Check kvm_rebooting in kvm_spurious_fault() 2019-09-25 15:23:33 +02:00
pci
pcmcia
perf perf test: Avoid infinite loop for task exit case 2019-10-15 08:36:22 -03:00
power platform-drivers-x86 for v5.4-2 2019-09-24 12:39:40 -07:00
scripts
spi
testing powerpc fixes for 5.4 #3 2019-10-12 14:13:55 -07:00
thermal/tmon
time
usb
virtio
vm
wmi
Makefile tools: Keep list of tools in alphabetical order 2019-08-14 10:59:59 -03:00