linux/tools
Namhyung Kim 0fba226548 perf lock contention: Revise needs_callstack() condition
It needs callstacks for two reasons:

 * for stack aggregation mode, the map key is the stack id and it can
   also show the full stack traces when -v is used

 * for other aggregation modes, the stack filter can be used to limit
   lock contentions from known call paths

The -v option is meaningful (in terms of stack trace) only for stack
aggregation mode, so it should not set the save_callstack for other
mode like with -t or -l options.

I've noticed this with the following command line:

  $ sudo ./perf lock con -ablv -E 3 -M 16 -- ./perf bench sched messaging
  ...
   contended   total wait     max wait     avg wait            address   symbol

          88      4.59 ms    108.07 us     52.13 us   ffff935757f46ec0    (spinlock)
          33    905.22 us     73.67 us     27.43 us   ffff935757f41700    (spinlock)
          28    703.69 us     79.28 us     25.13 us   ffff938a3d9b0c80   rq_lock (spinlock)

  === output for debug ===

  bad: 12272, total: 12421
  bad rate: 98.80 %
  histogram of failure reasons
         task: 8285
        stack: 3987    <---------- here
         time: 0
         data: 0

It should not have any failure on stacks since it doesn't use it.
No functional change intended.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230406210611.1622492-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2023-04-06 21:53:46 -03:00
..
accounting tools/accounting/procacct: remove some unused variables 2022-11-18 13:55:09 -08:00
arch perf bench syscall: Add fork syscall benchmark 2023-04-04 09:39:55 -03:00
bootconfig tools/bootconfig: fix single & used for logical condition 2023-02-22 08:27:35 +09:00
bpf bpftool: Use bpf_{btf,link,map,prog}_get_info_by_fd() 2023-02-16 15:32:45 -08:00
build tools build: Add a feature test for scandirat(), that is not implemented so far in musl and uclibc 2023-04-04 13:18:17 -03:00
certs
cgroup tools:cgroup:memcg_shrinker remove redundant import 2023-01-18 17:12:59 -08:00
counter
debugging
edid
firewire
firmware
gpio tools: gpio: fix -c option of gpio-event-mon 2023-01-27 14:05:46 +01:00
hv
iio tools/iio/iio_utils:fix memory leak 2023-01-21 17:52:26 +00:00
include tools: Rename __fallthrough to fallthrough 2023-04-06 21:41:00 -03:00
io_uring
kvm/kvm_stat
laptop
leds
lib tools api: Add io__getline 2023-04-04 13:23:59 -03:00
memory-model tools: memory-model: Make plain accesses carry dependencies 2023-01-03 20:47:04 -08:00
mm tools/mm: allow users to provide additional cflags/ldflags 2023-02-02 22:33:24 -08:00
net/ynl tools: ynl: fix enum-as-flags in the generic CLI 2023-03-08 23:28:21 -08:00
objtool Changes in this cycle were: 2023-03-02 09:45:34 -08:00
pci
pcmcia
perf perf lock contention: Revise needs_callstack() condition 2023-04-06 21:53:46 -03:00
power platform-drivers-x86 for v6.3-1 2023-02-21 17:32:50 -08:00
rcu
scripts tools: Add LoongArch build infrastructure 2023-02-25 22:12:18 +08:00
spi
testing perf tests test_bridge_fdb_stress.sh: Fix redirection of stderr to stdin 2023-04-04 09:39:55 -03:00
thermal
time
tracing tracing updates for 6.3: 2023-02-23 10:20:49 -08:00
usb
verification tools/rv: Remove unneeded semicolon 2023-01-31 19:21:12 -05:00
virtio tools/virtio: enable to build with retpoline 2023-02-20 19:26:59 -05:00
wmi
Makefile