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Groups > linux.kernel > #1244634
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples |
| Date | 2015-10-12 14:20 +0200 |
| Message-ID | <qiKf8-74w-3@gated-at.bofh.it> (permalink) |
| References | <qiHhh-2LN-29@gated-at.bofh.it> <qiHhh-2LN-31@gated-at.bofh.it> <qiK5s-6T6-9@gated-at.bofh.it> <qiK5s-6T6-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Oct 12, 2015 at 08:05:20PM +0800, Wangnan (F) wrote:
>
>
> On 2015/10/12 20:02, Peter Zijlstra wrote:
> >On Mon, Oct 12, 2015 at 09:02:42AM +0000, Kaixu Xia wrote:
> >>--- a/include/linux/perf_event.h
> >>+++ b/include/linux/perf_event.h
> >>@@ -483,6 +483,8 @@ struct perf_event {
> >> perf_overflow_handler_t overflow_handler;
> >> void *overflow_handler_context;
> >>+ atomic_t *sample_disable;
> >>+
> >> #ifdef CONFIG_EVENT_TRACING
> >> struct trace_event_call *tp_event;
> >> struct event_filter *filter;
> >>diff --git a/kernel/events/core.c b/kernel/events/core.c
> >>index b11756f..f6ef45c 100644
> >>--- a/kernel/events/core.c
> >>+++ b/kernel/events/core.c
> >>@@ -6337,6 +6337,9 @@ static int __perf_event_overflow(struct perf_event *event,
> >> irq_work_queue(&event->pending);
> >> }
> >>+ if ((event->sample_disable) && atomic_read(event->sample_disable))
> >>+ return ret;
> >>+
> >> if (event->overflow_handler)
> >> event->overflow_handler(event, data, regs);
> >> else
> >Try and guarantee sample_disable lives in the same cacheline as
> >overflow_handler.
>
> Could you please explain why we need them to be in a same cacheline?
Because otherwise you've just added a cacheline miss to this relatively
hot path.
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[RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples Kaixu Xia <xiakaixu@huawei.com> - 2015-10-12 11:10 +0200
Re: [RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples "Wangnan (F)" <wangnan0@huawei.com> - 2015-10-12 14:10 +0200
Re: [RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples Peter Zijlstra <peterz@infradead.org> - 2015-10-12 14:20 +0200
Re: [RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples Peter Zijlstra <peterz@infradead.org> - 2015-10-12 14:10 +0200
Re: [RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples Alexei Starovoitov <ast@plumgrid.com> - 2015-10-12 21:30 +0200
Re: [RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples xiakaixu <xiakaixu@huawei.com> - 2015-10-13 04:40 +0200
Re: [RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples Alexei Starovoitov <ast@plumgrid.com> - 2015-10-13 05:20 +0200
Re: [RFC PATCH 1/2] perf: Add the flag sample_disable not to output data on samples Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2015-10-13 14:10 +0200
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