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| author | Anne Macedo <retpolanne@posteo.net> | 2024-03-19 17:36:26 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2024-03-22 02:44:35 +0300 |
| commit | 2a5049b75d22c971e73501784f10548c1d69c407 (patch) | |
| tree | 2908ed0b1bc0c0b8e19686937dd6746cbae880fc | |
| parent | af34a16d3090f8a2f7eac24290209dacb9471132 (diff) | |
| download | linux-2a5049b75d22c971e73501784f10548c1d69c407.tar.xz | |
perf lock contention: Trim backtrace by skipping traceiter functions
The 'perf lock contention' program currently shows the caller of the locks
as __traceiter_contention_begin+0x??. This caller can be ignored, as it is
from the traceiter itself. Instead, it should show the real callers for
the locks.
When fiddling with the --stack-skip parameter, the actual callers for
the locks start to show up. However, just ignore the
__traceiter_contention_begin and the __traceiter_contention_end symbols
so the actual callers will show up.
Before this patch is applied:
sudo perf lock con -a -b -- sleep 3
contended total wait max wait avg wait type caller
8 2.33 s 2.28 s 291.18 ms rwlock:W __traceiter_contention_begin+0x44
4 2.33 s 2.28 s 582.35 ms rwlock:W __traceiter_contention_begin+0x44
7 140.30 ms 46.77 ms 20.04 ms rwlock:W __traceiter_contention_begin+0x44
2 63.35 ms 33.76 ms 31.68 ms mutex trace_contention_begin+0x84
2 46.74 ms 46.73 ms 23.37 ms rwlock:W __traceiter_contention_begin+0x44
1 13.54 us 13.54 us 13.54 us mutex trace_contention_begin+0x84
1 3.67 us 3.67 us 3.67 us rwsem:R __traceiter_contention_begin+0x44
Before this patch is applied - using --stack-skip 5
sudo perf lock con --stack-skip 5 -a -b -- sleep 3
contended total wait max wait avg wait type caller
2 2.24 s 2.24 s 1.12 s rwlock:W do_epoll_wait+0x5a0
4 1.65 s 824.21 ms 412.08 ms rwlock:W do_exit+0x338
2 824.35 ms 824.29 ms 412.17 ms spinlock get_signal+0x108
2 824.14 ms 824.14 ms 412.07 ms rwlock:W release_task+0x68
1 25.22 ms 25.22 ms 25.22 ms mutex cgroup_kn_lock_live+0x58
1 24.71 us 24.71 us 24.71 us spinlock do_exit+0x44
1 22.04 us 22.04 us 22.04 us rwsem:R lock_mm_and_find_vma+0xb0
After this patch is applied:
sudo ./perf lock con -a -b -- sleep 3
contended total wait max wait avg wait type caller
4 4.13 s 2.07 s 1.03 s rwlock:W release_task+0x68
2 2.07 s 2.07 s 1.03 s rwlock:R mm_update_next_owner+0x50
2 2.07 s 2.07 s 1.03 s rwlock:W do_exit+0x338
1 41.56 ms 41.56 ms 41.56 ms mutex cgroup_kn_lock_live+0x58
2 36.12 us 18.83 us 18.06 us rwlock:W do_exit+0x338
Signed-off-by: Anne Macedo <retpolanne@posteo.net>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240319143629.3422590-1-retpolanne@posteo.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/util/machine.c | 24 | ||||
| -rw-r--r-- | tools/perf/util/machine.h | 2 |
2 files changed, 25 insertions, 1 deletions
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 527517db3182..5eb9044bc223 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -3266,6 +3266,17 @@ bool machine__is_lock_function(struct machine *machine, u64 addr) sym = machine__find_kernel_symbol_by_name(machine, "__lock_text_end", &kmap); machine->lock.text_end = map__unmap_ip(kmap, sym->start); + + sym = machine__find_kernel_symbol_by_name(machine, "__traceiter_contention_begin", &kmap); + if (sym) { + machine->traceiter.text_start = map__unmap_ip(kmap, sym->start); + machine->traceiter.text_end = map__unmap_ip(kmap, sym->end); + } + sym = machine__find_kernel_symbol_by_name(machine, "trace_contention_begin", &kmap); + if (sym) { + machine->trace.text_start = map__unmap_ip(kmap, sym->start); + machine->trace.text_end = map__unmap_ip(kmap, sym->end); + } } /* failed to get kernel symbols */ @@ -3280,5 +3291,18 @@ bool machine__is_lock_function(struct machine *machine, u64 addr) if (machine->lock.text_start <= addr && addr < machine->lock.text_end) return true; + /* traceiter functions currently don't have their own section + * but we consider them lock functions + */ + if (machine->traceiter.text_start != 0) { + if (machine->traceiter.text_start <= addr && addr < machine->traceiter.text_end) + return true; + } + + if (machine->trace.text_start != 0) { + if (machine->trace.text_start <= addr && addr < machine->trace.text_end) + return true; + } + return false; } diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index e28c787616fe..4312f6db6de0 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -49,7 +49,7 @@ struct machine { struct { u64 text_start; u64 text_end; - } sched, lock; + } sched, lock, traceiter, trace; pid_t *current_tid; size_t current_tid_sz; union { /* Tool specific area */ |