From: David Ahern <dsahern@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
"zhangwei(Jovi)" <jovi.zhangwei@huawei.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] tracing/perf: perf_trace_buf/perf_xxx hacks.
Date: Thu, 20 Jun 2013 12:53:01 -0600 [thread overview]
Message-ID: <51C34F8D.2000806@gmail.com> (raw)
In-Reply-To: <1371754078.18733.106.camel@gandalf.local.home>
On 6/20/13 12:47 PM, Steven Rostedt wrote:
> On Thu, 2013-06-20 at 12:35 -0600, David Ahern wrote:
>> On 6/20/13 12:23 PM, Steven Rostedt wrote:
>>>
>>> I ran this:
>>>
>>> perf stat --repeat 100 -- perf bench sched pipe > /tmp/perf-bench-sched.{before, after}
>>
>> You want to compare:
>> perf stat --repeat 100 -p 1 -- perf bench sched pipe
>>
>> so that event is tagged to pid 1 and not the perf-bench workload.
>
> I guess I'm a bit confused. What's the significance of measuring pid 1
> (init)?
I believe Oleg's point is the overhead for tasks without events
associated with them. To show that create an event tagged to the init
task and then run some workload -- like perf bench shed pipe. It shows
that all tasks take a hit, not just the one getting profiled.
David
next prev parent reply other threads:[~2013-06-20 18:53 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-18 19:21 [PATCH 0/3] tracing/perf: perf_trace_buf/perf_xxx hacks Oleg Nesterov
2013-06-18 19:22 ` [PATCH 1/3] tracing/perf: expand TRACE_EVENT(sched_stat_runtime) Oleg Nesterov
2013-06-18 19:22 ` [PATCH 2/3] tracing/perf: reimplement TP_perf_assign() logic Oleg Nesterov
2013-06-18 19:22 ` [PATCH 3/3] tracing/perf: Avoid perf_trace_buf_*() in perf_trace_##call() when possible Oleg Nesterov
2013-06-18 20:02 ` Steven Rostedt
2013-06-19 18:12 ` Oleg Nesterov
2013-06-19 18:24 ` Steven Rostedt
2013-06-19 12:10 ` [PATCH 0/3] tracing/perf: perf_trace_buf/perf_xxx hacks Peter Zijlstra
2013-06-19 15:28 ` Oleg Nesterov
2013-06-19 17:51 ` Oleg Nesterov
2013-06-19 18:50 ` David Ahern
2013-06-19 19:58 ` Oleg Nesterov
2013-06-20 18:23 ` Steven Rostedt
2013-06-20 18:35 ` David Ahern
2013-06-20 18:47 ` Steven Rostedt
2013-06-20 18:53 ` David Ahern [this message]
2013-06-20 18:53 ` Steven Rostedt
2013-06-20 22:20 ` Steven Rostedt
2013-07-18 3:06 ` Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51C34F8D.2000806@gmail.com \
--to=dsahern@gmail.com \
--cc=fweisbec@gmail.com \
--cc=jovi.zhangwei@huawei.com \
--cc=linux-kernel@vger.kernel.org \
--cc=masami.hiramatsu.pt@hitachi.com \
--cc=mingo@redhat.com \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=srikar@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).