From: Ingo Molnar <mingo@kernel.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
linux-kernel@vger.kernel.org,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Corey Ashford <cjashfor@linux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@elte.hu>, Paul Mackerras <paulus@samba.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Don Zickus <dzickus@redhat.com>,
Andi Kleen <ak@linux.jf.intel.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Stephane Eranian <eranian@google.com>
Subject: Re: [RFC 00/21] perf tools: Add toggling events support
Date: Thu, 26 Sep 2013 09:03:07 +0200 [thread overview]
Message-ID: <20130926070307.GE19090@gmail.com> (raw)
In-Reply-To: <20130925191216.GE2018@tassilo.jf.intel.com>
* Andi Kleen <ak@linux.intel.com> wrote:
> On Wed, Sep 25, 2013 at 02:50:26PM +0200, Jiri Olsa wrote:
> > hi,
> > sending *RFC* for toggling events support.
> >
> > Adding perf interface that allows to create toggle events, which can
> > enable or disable another event. Whenever the toggle event is triggered
> > (has overflow), it toggles another event state and either starts or
> > stops it.
> >
> > The goal is to be able to create toggling tracepoint events to enable and
> > disable HW counters, but the interface is generic enough to be used for
> > any kind of event.
>
> Haven't read the patches, but frequent full event switch in/out seems
> very expensive. If someone puts that switch on a common function it
> would likely disturb things quite a bit.
>
> It would be better to keep counting and just do RDPMC on the switch
> points, and then subtract for counting. For sampling could need a MSR
> write to enable/disable. Still somewhat expensive, but nowhere near as
> bad as a full switch.
This is essentially an optimized event switch and should probably be done
on a higher level so that other instances of event/context switching
benefit as well.
Thanks,
Ingo
next prev parent reply other threads:[~2013-09-26 7:03 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-25 12:50 [RFC 00/21] perf tools: Add toggling events support Jiri Olsa
2013-09-25 12:50 ` [PATCH 01/21] perf tools: Introduce perf_evlist__wait_workload function Jiri Olsa
2013-09-25 12:50 ` [PATCH 02/21] perf tools: Separate sys_perf_event_open call into evsel_open Jiri Olsa
2013-09-25 12:50 ` [PATCH 03/21] perf x86: Update event count properly for read syscall Jiri Olsa
2013-09-25 12:50 ` [PATCH 04/21] perf: Move event state initialization before/behind the pmu add/del calls Jiri Olsa
2013-09-25 12:50 ` [PATCH 05/21] perf: Add event toggle sys_perf_event_open interface Jiri Olsa
2013-09-25 22:36 ` Sukadev Bhattiprolu
2013-09-26 12:27 ` Jiri Olsa
2013-09-25 12:50 ` [PATCH 06/21] perf: Add event toggle ioctl interface Jiri Olsa
2013-09-25 19:46 ` Vince Weaver
2013-09-26 12:30 ` Jiri Olsa
2013-09-26 13:03 ` Vince Weaver
2013-09-25 12:50 ` [PATCH 07/21] perf: Toggle whole group in toggle event overflow Jiri Olsa
2013-09-25 12:50 ` [PATCH 08/21] perf: Add new 'paused' attribute Jiri Olsa
2013-09-25 22:41 ` Sukadev Bhattiprolu
2013-09-26 12:24 ` Jiri Olsa
2013-09-25 12:50 ` [PATCH 09/21] perf: Account toggle masters for toggled event Jiri Olsa
2013-09-25 12:50 ` [PATCH 10/21] perf: Be more specific on pmu related event init naming Jiri Olsa
2013-09-25 12:50 ` [PATCH 11/21] perf: Split allocation and initialization code Jiri Olsa
2013-09-25 12:50 ` [PATCH 12/21] perf: Support event inheritance for toggle feature Jiri Olsa
2013-09-25 12:50 ` [PATCH 13/21] perf tests: Adding event simple toggling test Jiri Olsa
2013-09-25 12:50 ` [PATCH 14/21] perf tests: Adding event group " Jiri Olsa
2013-09-25 12:50 ` [PATCH 15/21] perf tests: Adding event inherit " Jiri Olsa
2013-09-25 12:50 ` [PATCH 16/21] perf tools: Allow numeric event to change name via name term Jiri Olsa
2013-09-25 12:50 ` [PATCH 17/21] perf tools: Add event_config_optional parsing rule Jiri Olsa
2013-09-25 12:50 ` [PATCH 18/21] perf tools: Rename term related parsing function/variable properly Jiri Olsa
2013-09-25 12:50 ` [PATCH 19/21] perf tools: Carry term string value for symbols events Jiri Olsa
2013-09-25 12:50 ` [PATCH 20/21] perf tools: Add support to parse event on/off toggle terms Jiri Olsa
2013-09-25 12:50 ` [PATCH 21/21] perf tools: Add record/stat support for toggling events Jiri Olsa
2013-09-25 19:12 ` [RFC 00/21] perf tools: Add toggling events support Andi Kleen
2013-09-26 7:03 ` Ingo Molnar [this message]
2013-09-26 15:45 ` Andi Kleen
2013-09-26 12:11 ` Jiri Olsa
2013-09-26 11:31 ` Stephane Eranian
2013-09-26 12:20 ` Jiri Olsa
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=20130926070307.GE19090@gmail.com \
--to=mingo@kernel.org \
--cc=a.p.zijlstra@chello.nl \
--cc=acme@redhat.com \
--cc=adrian.hunter@intel.com \
--cc=ak@linux.intel.com \
--cc=ak@linux.jf.intel.com \
--cc=cjashfor@linux.vnet.ibm.com \
--cc=dzickus@redhat.com \
--cc=eranian@google.com \
--cc=fweisbec@gmail.com \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=paulus@samba.org \
/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