linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Tom Zanussi <tom.zanussi@linux.intel.com>
To: "Joel Fernandes (Google)" <joel.opensrc@gmail.com>
Cc: rostedt@goodmis.org, tglx@linutronix.de, mhiramat@kernel.org,
	namhyung@kernel.org, vedang.patel@intel.com,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-rt-users@vger.kernel.org
Subject: Re: [PATCH 00/32] tracing: Inter-event (e.g. latency) support
Date: Wed, 12 Jul 2017 14:17:38 -0500	[thread overview]
Message-ID: <1499887058.3995.28.camel@tzanussi-mobl.amr.corp.intel.com> (raw)
In-Reply-To: <CAEi0qN=FNd056iBufikmRuuVLUPZbsYH=bAZNVnaOmRVjoQHuw@mail.gmail.com>

Hi Joel,

Sorry for the delayed reply, was out for the holidays..

On Sat, 2017-07-01 at 00:01 -0700, Joel Fernandes (Google) wrote:
> Hi Tom,
> Nice series and nice ELC talk as well. Thanks.
> 
> On Mon, Jun 26, 2017 at 3:49 PM, Tom Zanussi
> <tom.zanussi@linux.intel.com> wrote:
> > This patchset adds support for 'inter-event' quantities to the trace
> > event subsystem.  The most important example of inter-event quantities
> > are latencies, or the time differences between two events.
> 
> I tried your patches out and they are working fine for me. I will test
> them out more.
> 
> I think for the wakeup latency in your examples, its better / more
> accurate to use sched_waking instead of sched_wakeup tracepoint? [1]
> 

Yeah, makes sense - thanks for pointing it out.

> Also, one other comment I had is, it would be nice to suppress the
> output of individual trace events that are part of the synthetic event
> into the trace buffer. Otherwise I feel the value of it is slightly
> diminished - because one can simply post-process the individual
> non-synthetic trace events themselves to get wake up latencies which
> the synthetic events is trying to calculate in the first place.
> Inorder to conserve space, if a user doesn't care about individual
> events, and just the synthetic events then the individual ones
> shouldn't be written to the trace buffer IMO.
> 

Yes, you're right, this is also something I need to fix.  I added a flag
to avoid discards, but this has the effect of, well, avoiding discards,
so unwanted events appear in the trace buffer.  Also, regardless, any
trigger that exists simply to provide input to a synthetic event should
be filtered out, regardless of the enable state.  I'll have to think
about a better way do handle all this...

Thanks,

Tom

> -Joel
> 
> [1] commit fbd705a0c6184580d0e2fbcbd47a37b6e5822511 (sched: Introduce
> the 'trace_sched_waking' tracepoint)

  reply	other threads:[~2017-07-12 19:17 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-26 22:49 [PATCH 00/32] tracing: Inter-event (e.g. latency) support Tom Zanussi
2017-06-26 22:49 ` [PATCH 01/32] tracing: Add hist_field_name() accessor Tom Zanussi
2017-07-13  6:49   ` Piotr Gregor
2017-07-13 14:41     ` Tom Zanussi
2017-07-14  2:19   ` Namhyung Kim
2017-06-26 22:49 ` [PATCH 02/32] tracing: Reimplement log2 Tom Zanussi
2017-07-14  2:33   ` Namhyung Kim
2017-07-14 16:13     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 03/32] ring-buffer: Add interface for setting absolute time stamps Tom Zanussi
2017-07-14  5:25   ` Namhyung Kim
2017-07-14 16:14     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 04/32] ring-buffer: Redefine the unimplemented RINGBUF_TIME_TIME_STAMP Tom Zanussi
2017-07-02  8:51   ` Joel Fernandes (Google)
2017-06-26 22:49 ` [PATCH 05/32] tracing: Give event triggers access to ring_buffer_event Tom Zanussi
2017-06-26 22:49 ` [PATCH 06/32] tracing: Add ring buffer event param to hist field functions Tom Zanussi
2017-06-26 22:49 ` [PATCH 07/32] tracing: Increase tracing map KEYS_MAX size Tom Zanussi
2017-06-26 22:49 ` [PATCH 08/32] tracing: Break out hist trigger assignment parsing Tom Zanussi
2017-06-26 22:49 ` [PATCH 09/32] tracing: Make traceprobe parsing code reusable Tom Zanussi
2017-06-26 22:49 ` [PATCH 10/32] tracing: Add NO_DISCARD event file flag Tom Zanussi
2017-06-26 22:49 ` [PATCH 11/32] tracing: Add post-trigger flag to hist trigger command Tom Zanussi
2017-06-26 22:49 ` [PATCH 12/32] tracing: Add hist trigger timestamp support Tom Zanussi
2017-07-17  6:00   ` Namhyung Kim
2017-07-17 16:57     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 13/32] tracing: Add per-element variable support to tracing_map Tom Zanussi
2017-06-26 22:49 ` [PATCH 14/32] tracing: Add hist_data member to hist_field Tom Zanussi
2017-06-26 22:49 ` [PATCH 15/32] tracing: Add usecs modifier for hist trigger timestamps Tom Zanussi
2017-06-26 22:49 ` [PATCH 16/32] tracing: Add variable support to hist triggers Tom Zanussi
2017-07-19  1:07   ` Namhyung Kim
2017-07-19 15:40     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 17/32] tracing: Account for variables in named trigger compatibility Tom Zanussi
2017-06-26 22:49 ` [PATCH 18/32] tracing: Add simple expression support to hist triggers Tom Zanussi
2017-07-21  2:02   ` Namhyung Kim
2017-07-21 16:29     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 19/32] tracing: Add variable reference handling " Tom Zanussi
2017-07-21  3:31   ` Namhyung Kim
2017-07-21 16:41     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 20/32] tracing: Add support for dynamic tracepoints Tom Zanussi
2017-06-26 22:49 ` [PATCH 21/32] tracing: Add hist trigger action hook Tom Zanussi
2017-06-26 22:49 ` [PATCH 22/32] tracing: Add support for 'synthetic' events Tom Zanussi
2017-07-23 12:00   ` Namhyung Kim
2017-07-24 16:11     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 23/32] tracing: Add 'onmatch' hist trigger action support Tom Zanussi
2017-07-23 15:12   ` Namhyung Kim
2017-07-24 16:17     ` Tom Zanussi
2017-07-26  2:40   ` Namhyung Kim
2017-07-26 16:38     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 24/32] tracing: Add 'onmax' " Tom Zanussi
2017-07-26  3:04   ` Namhyung Kim
2017-07-26 16:45     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 25/32] tracing: Allow whitespace to surround hist trigger filter Tom Zanussi
2017-06-26 22:49 ` [PATCH 26/32] tracing: Make duplicate count from tracing_map available Tom Zanussi
2017-06-26 22:49 ` [PATCH 27/32] tracing: Add cpu field for hist triggers Tom Zanussi
2017-06-26 22:49 ` [PATCH 28/32] tracing: Add hist trigger support for variable reference aliases Tom Zanussi
2017-06-26 22:49 ` [PATCH 29/32] tracing: Add 'last error' error facility for hist triggers Tom Zanussi
2017-07-26  4:39   ` Namhyung Kim
2017-07-26 16:47     ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 30/32] tracing: Add inter-event hist trigger Documentation Tom Zanussi
2017-06-26 22:49 ` [PATCH 31/32] tracing: Make tracing_set_clock() non-static Tom Zanussi
2017-06-26 22:49 ` [PATCH 32/32] tracing: Add a clock attribute for hist triggers Tom Zanussi
2017-06-27 14:58 ` [PATCH 00/32] tracing: Inter-event (e.g. latency) support Steven Rostedt
2017-06-28 14:21 ` Masami Hiramatsu
2017-06-28 19:09   ` Tom Zanussi
2017-07-01  7:01 ` Joel Fernandes (Google)
2017-07-12 19:17   ` Tom Zanussi [this message]
2017-07-04 16:12 ` Sebastian Andrzej Siewior
2017-07-12 19:20   ` Tom Zanussi

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=1499887058.3995.28.camel@tzanussi-mobl.amr.corp.intel.com \
    --to=tom.zanussi@linux.intel.com \
    --cc=joel.opensrc@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rt-users@vger.kernel.org \
    --cc=mhiramat@kernel.org \
    --cc=namhyung@kernel.org \
    --cc=rostedt@goodmis.org \
    --cc=tglx@linutronix.de \
    --cc=vedang.patel@intel.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).