* [RFC PATCH bpf-next] libbpf: remove sample_period init in perf_buffer
@ 2025-04-22 9:15 Tao Chen
2025-04-22 13:43 ` Jiri Olsa
0 siblings, 1 reply; 5+ messages in thread
From: Tao Chen @ 2025-04-22 9:15 UTC (permalink / raw)
To: andrii, eddyz87, ast, daniel, martin.lau, song, yonghong.song,
john.fastabend, kpsingh, sdf, haoluo, jolsa
Cc: bpf, linux-kernel, Tao Chen
It seems that sample_period no used in perf buffer, actually only
wakeup_events valid about events aggregation for wakeup. So remove
it to avoid causing confusion.
Fixes: fb84b8224655 ("libbpf: add perf buffer API")
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
---
tools/lib/bpf/libbpf.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 194809da5172..1830e3c011a5 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -13306,7 +13306,6 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
attr.config = PERF_COUNT_SW_BPF_OUTPUT;
attr.type = PERF_TYPE_SOFTWARE;
attr.sample_type = PERF_SAMPLE_RAW;
- attr.sample_period = sample_period;
attr.wakeup_events = sample_period;
p.attr = &attr;
--
2.43.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [RFC PATCH bpf-next] libbpf: remove sample_period init in perf_buffer
2025-04-22 9:15 [RFC PATCH bpf-next] libbpf: remove sample_period init in perf_buffer Tao Chen
@ 2025-04-22 13:43 ` Jiri Olsa
2025-04-22 19:05 ` Namhyung Kim
0 siblings, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2025-04-22 13:43 UTC (permalink / raw)
To: Tao Chen, Namhyung Kim
Cc: andrii, eddyz87, ast, daniel, martin.lau, song, yonghong.song,
john.fastabend, kpsingh, sdf, haoluo, bpf, linux-kernel
On Tue, Apr 22, 2025 at 05:15:58PM +0800, Tao Chen wrote:
> It seems that sample_period no used in perf buffer, actually only
> wakeup_events valid about events aggregation for wakeup. So remove
> it to avoid causing confusion.
I don't see too much confusion in keeping it, but I think it
should be safe to remove it
PERF_COUNT_SW_BPF_OUTPUT is "trigered" by bpf_perf_event_output,
AFAICS there's no path checking on sample_period for this event
used in context of perf_buffer__new, Namhyung, thoughts?
thanks,
jirka
>
> Fixes: fb84b8224655 ("libbpf: add perf buffer API")
> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
> ---
> tools/lib/bpf/libbpf.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 194809da5172..1830e3c011a5 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -13306,7 +13306,6 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
> attr.config = PERF_COUNT_SW_BPF_OUTPUT;
> attr.type = PERF_TYPE_SOFTWARE;
> attr.sample_type = PERF_SAMPLE_RAW;
> - attr.sample_period = sample_period;
> attr.wakeup_events = sample_period;
>
> p.attr = &attr;
> --
> 2.43.0
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH bpf-next] libbpf: remove sample_period init in perf_buffer
2025-04-22 13:43 ` Jiri Olsa
@ 2025-04-22 19:05 ` Namhyung Kim
2025-04-23 15:51 ` Jiri Olsa
0 siblings, 1 reply; 5+ messages in thread
From: Namhyung Kim @ 2025-04-22 19:05 UTC (permalink / raw)
To: Jiri Olsa
Cc: Tao Chen, andrii, eddyz87, ast, daniel, martin.lau, song,
yonghong.song, john.fastabend, kpsingh, sdf, haoluo, bpf,
linux-kernel
Hello,
On Tue, Apr 22, 2025 at 03:43:43PM +0200, Jiri Olsa wrote:
> On Tue, Apr 22, 2025 at 05:15:58PM +0800, Tao Chen wrote:
> > It seems that sample_period no used in perf buffer, actually only
> > wakeup_events valid about events aggregation for wakeup. So remove
> > it to avoid causing confusion.
>
> I don't see too much confusion in keeping it, but I think it
> should be safe to remove it
>
> PERF_COUNT_SW_BPF_OUTPUT is "trigered" by bpf_perf_event_output,
> AFAICS there's no path checking on sample_period for this event
> used in context of perf_buffer__new, Namhyung, thoughts?
It seems to be ok to call mmap(2) for non-sampling events.
Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks,
Namhyung
>
> >
> > Fixes: fb84b8224655 ("libbpf: add perf buffer API")
> > Signed-off-by: Tao Chen <chen.dylane@linux.dev>
> > ---
> > tools/lib/bpf/libbpf.c | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index 194809da5172..1830e3c011a5 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -13306,7 +13306,6 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
> > attr.config = PERF_COUNT_SW_BPF_OUTPUT;
> > attr.type = PERF_TYPE_SOFTWARE;
> > attr.sample_type = PERF_SAMPLE_RAW;
> > - attr.sample_period = sample_period;
> > attr.wakeup_events = sample_period;
> >
> > p.attr = &attr;
> > --
> > 2.43.0
> >
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH bpf-next] libbpf: remove sample_period init in perf_buffer
2025-04-22 19:05 ` Namhyung Kim
@ 2025-04-23 15:51 ` Jiri Olsa
2025-04-23 16:26 ` Tao Chen
0 siblings, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2025-04-23 15:51 UTC (permalink / raw)
To: Namhyung Kim
Cc: Jiri Olsa, Tao Chen, andrii, eddyz87, ast, daniel, martin.lau,
song, yonghong.song, john.fastabend, kpsingh, sdf, haoluo, bpf,
linux-kernel
On Tue, Apr 22, 2025 at 12:05:55PM -0700, Namhyung Kim wrote:
> Hello,
>
> On Tue, Apr 22, 2025 at 03:43:43PM +0200, Jiri Olsa wrote:
> > On Tue, Apr 22, 2025 at 05:15:58PM +0800, Tao Chen wrote:
> > > It seems that sample_period no used in perf buffer, actually only
> > > wakeup_events valid about events aggregation for wakeup. So remove
> > > it to avoid causing confusion.
> >
> > I don't see too much confusion in keeping it, but I think it
> > should be safe to remove it
> >
> > PERF_COUNT_SW_BPF_OUTPUT is "trigered" by bpf_perf_event_output,
> > AFAICS there's no path checking on sample_period for this event
> > used in context of perf_buffer__new, Namhyung, thoughts?
>
> It seems to be ok to call mmap(2) for non-sampling events.
>
> Acked-by: Namhyung Kim <namhyung@kernel.org>
Tao Chen,
could you please resend without rfc tag? plz keeps acks
Acked-by: Jiri Olsa <jolsa@kernel.org>
thanks,
jirka
>
> Thanks,
> Namhyung
>
> >
> > >
> > > Fixes: fb84b8224655 ("libbpf: add perf buffer API")
> > > Signed-off-by: Tao Chen <chen.dylane@linux.dev>
> > > ---
> > > tools/lib/bpf/libbpf.c | 1 -
> > > 1 file changed, 1 deletion(-)
> > >
> > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > > index 194809da5172..1830e3c011a5 100644
> > > --- a/tools/lib/bpf/libbpf.c
> > > +++ b/tools/lib/bpf/libbpf.c
> > > @@ -13306,7 +13306,6 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
> > > attr.config = PERF_COUNT_SW_BPF_OUTPUT;
> > > attr.type = PERF_TYPE_SOFTWARE;
> > > attr.sample_type = PERF_SAMPLE_RAW;
> > > - attr.sample_period = sample_period;
> > > attr.wakeup_events = sample_period;
> > >
> > > p.attr = &attr;
> > > --
> > > 2.43.0
> > >
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH bpf-next] libbpf: remove sample_period init in perf_buffer
2025-04-23 15:51 ` Jiri Olsa
@ 2025-04-23 16:26 ` Tao Chen
0 siblings, 0 replies; 5+ messages in thread
From: Tao Chen @ 2025-04-23 16:26 UTC (permalink / raw)
To: Jiri Olsa, Namhyung Kim
Cc: andrii, eddyz87, ast, daniel, martin.lau, song, yonghong.song,
john.fastabend, kpsingh, sdf, haoluo, bpf, linux-kernel
在 2025/4/23 23:51, Jiri Olsa 写道:
> On Tue, Apr 22, 2025 at 12:05:55PM -0700, Namhyung Kim wrote:
>> Hello,
>>
>> On Tue, Apr 22, 2025 at 03:43:43PM +0200, Jiri Olsa wrote:
>>> On Tue, Apr 22, 2025 at 05:15:58PM +0800, Tao Chen wrote:
>>>> It seems that sample_period no used in perf buffer, actually only
>>>> wakeup_events valid about events aggregation for wakeup. So remove
>>>> it to avoid causing confusion.
>>>
>>> I don't see too much confusion in keeping it, but I think it
>>> should be safe to remove it
>>>
>>> PERF_COUNT_SW_BPF_OUTPUT is "trigered" by bpf_perf_event_output,
>>> AFAICS there's no path checking on sample_period for this event
>>> used in context of perf_buffer__new, Namhyung, thoughts?
>>
>> It seems to be ok to call mmap(2) for non-sampling events.
>>
>> Acked-by: Namhyung Kim <namhyung@kernel.org>
>
> Tao Chen,
> could you please resend without rfc tag? plz keeps acks
>
sure, will resend it, thanks.
> Acked-by: Jiri Olsa <jolsa@kernel.org>
>
> thanks,
> jirka
>
>
>>
>> Thanks,
>> Namhyung
>>
>>>
>>>>
>>>> Fixes: fb84b8224655 ("libbpf: add perf buffer API")
>>>> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
>>>> ---
>>>> tools/lib/bpf/libbpf.c | 1 -
>>>> 1 file changed, 1 deletion(-)
>>>>
>>>> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
>>>> index 194809da5172..1830e3c011a5 100644
>>>> --- a/tools/lib/bpf/libbpf.c
>>>> +++ b/tools/lib/bpf/libbpf.c
>>>> @@ -13306,7 +13306,6 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
>>>> attr.config = PERF_COUNT_SW_BPF_OUTPUT;
>>>> attr.type = PERF_TYPE_SOFTWARE;
>>>> attr.sample_type = PERF_SAMPLE_RAW;
>>>> - attr.sample_period = sample_period;
>>>> attr.wakeup_events = sample_period;
>>>>
>>>> p.attr = &attr;
>>>> --
>>>> 2.43.0
>>>>
--
Best Regards
Tao Chen
^ permalink raw reply [flat|nested] 5+ messages in thread
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2025-04-22 9:15 [RFC PATCH bpf-next] libbpf: remove sample_period init in perf_buffer Tao Chen
2025-04-22 13:43 ` Jiri Olsa
2025-04-22 19:05 ` Namhyung Kim
2025-04-23 15:51 ` Jiri Olsa
2025-04-23 16:26 ` Tao Chen
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