tools/perf/util/machine.c | 21 +++++++++++++++++++++ tools/perf/util/machine.h | 2 +- 2 files changed, 22 insertions(+), 1 deletion(-)
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
changes since v1:
- consider trace_contention and __traceiter_contention functions as
optional (i.e. check if sym is null to avoid segfault)
changes since v0:
- skip trace_contention functions
- use sym->end instead of __traceiter_contention_end for text_end
Signed-off-by: Anne Macedo <retpolanne@posteo.net>
---
tools/perf/util/machine.c | 21 +++++++++++++++++++++
tools/perf/util/machine.h | 2 +-
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 527517db3182..968f69364f9a 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -3266,6 +3266,18 @@ 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 +3292,14 @@ 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 <= addr && addr < machine->traceiter.text_end)
+ return true;
+
+ 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 */
--
2.39.2On Mon, Mar 11, 2024 at 3:57 PM Anne Macedo <retpolanne@posteo.net> wrote:
>
> 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
>
> changes since v1:
>
> - consider trace_contention and __traceiter_contention functions as
> optional (i.e. check if sym is null to avoid segfault)
>
> changes since v0:
>
> - skip trace_contention functions
> - use sym->end instead of __traceiter_contention_end for text_end
>
> Signed-off-by: Anne Macedo <retpolanne@posteo.net>
> ---
> tools/perf/util/machine.c | 21 +++++++++++++++++++++
> tools/perf/util/machine.h | 2 +-
> 2 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index 527517db3182..968f69364f9a 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -3266,6 +3266,18 @@ 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 +3292,14 @@ 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 <= addr && addr < machine->traceiter.text_end)
> + return true;
> +
> + if (machine->trace.text_start <= addr && addr < machine->trace.text_end)
> + return true;
You cannot simply check these as they are set optionally.
Thanks,
Namhyung
> +
> 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 */
> --
> 2.39.2
>
Namhyung Kim <namhyung@kernel.org> writes:
> On Mon, Mar 11, 2024 at 3:57 PM Anne Macedo <retpolanne@posteo.net> wrote:
>>
>> 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
>>
>> changes since v1:
>>
>> - consider trace_contention and __traceiter_contention functions as
>> optional (i.e. check if sym is null to avoid segfault)
>>
>> changes since v0:
>>
>> - skip trace_contention functions
>> - use sym->end instead of __traceiter_contention_end for text_end
>>
>> Signed-off-by: Anne Macedo <retpolanne@posteo.net>
>> ---
>> tools/perf/util/machine.c | 21 +++++++++++++++++++++
>> tools/perf/util/machine.h | 2 +-
>> 2 files changed, 22 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
>> index 527517db3182..968f69364f9a 100644
>> --- a/tools/perf/util/machine.c
>> +++ b/tools/perf/util/machine.c
>> @@ -3266,6 +3266,18 @@ 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 +3292,14 @@ 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 <= addr && addr < machine->traceiter.text_end)
>> + return true;
>> +
>> + if (machine->trace.text_start <= addr && addr < machine->trace.text_end)
>> + return true;
>
> You cannot simply check these as they are set optionally.
>
Should I move them to the same if block where I check for the sym?
>
> Thanks,
> Namhyung
>
>
>> +
>> 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 */
>> --
>> 2.39.2
>>
Thanks, Anne
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