From: Ingo Molnar <mingo@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "平松雅巳 / HIRAMATU，MASAMI" <masami.hiramatsu.pt@hitachi.com>,
"'Martin KaFai Lau'" <kafai@fb.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
"Josef Bacik" <jbacik@fb.com>, "Kernel Team" <kernel-team@fb.com>
Subject: Re: [PATCH RESEND] kprobe: Use percpu counter to collect nhit statistics
Date: Tue, 9 Feb 2016 11:09:36 +0100 [thread overview]
Message-ID: <20160209100936.GA8273@gmail.com> (raw)
In-Reply-To: <20160204081957.3c31f719@gandalf.local.home>
* Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 4 Feb 2016 10:24:12 +0000
> 平松雅巳 / HIRAMATU，MASAMI <masami.hiramatsu.pt@hitachi.com> wrote:
>
> > From: Martin KaFai Lau [mailto:kafai@fb.com]
> > >
> > >When doing ebpf+kprobe on some hot TCP functions (e.g.
> > >tcp_rcv_established), the kprobe_dispatcher shows up in 'perf report'.
> > >
> > >In kprobe_dispatcher(), there is a lot of cache bouncing
> > >in 'tk->nhit++'. 'tk->nhit' and 'tk->tp.flags' also share
> > >the same cacheline.
> > >
> >
> > Ingo, could you consider to merge this?
> >
>
> Ingo, you can also add my
>
> Acked-by: Steven Rostedt <rostedt@goodmis.org>
Yeah, nice optimization, picked it up - thanks guys!
Ingo
next prev parent reply other threads:[~2016-02-09 10:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 20:28 [PATCH RESEND] kprobe: Use percpu counter to collect nhit statistics Martin KaFai Lau
2016-02-04 10:24 ` 平松雅巳 / HIRAMATU，MASAMI
2016-02-04 13:19 ` Steven Rostedt
2016-02-09 10:09 ` Ingo Molnar [this message]
2016-02-09 12:20 ` [tip:perf/core] kprobes: Optimize hot path by using percpu counter to collect 'nhit' statistics tip-bot for Martin KaFai Lau
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