From: Peter Zijlstra <peterz@infradead.org>
To: eranian@google.com
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, paulus@samba.org,
fweisbec@gmail.com, perfmon2-devel@lists.sf.net,
robert.richter@amd.com, eranian@gmail.com
Subject: Re: [PATCH] perf_events: add sampling period randomization support
Date: Tue, 02 Mar 2010 09:21:28 +0100 [thread overview]
Message-ID: <1267518088.25158.0.camel@laptop> (raw)
In-Reply-To: <1267510029-19750-1-git-send-email-eranian@google.com>
On Mon, 2010-03-01 at 22:07 -0800, eranian@google.com wrote:
> This patch adds support for randomizing the sampling period.
> Randomization is very useful to mitigate the bias that exists
> with sampling. The random number generator does not need to
> be sophisticated. This patch uses the builtin random32()
> generator.
>
> The user activates randomization by setting the perf_event_attr.random
> field to 1 and by passing a bitmask to control the range of variation
> above the base period. Period will vary from period to period & mask.
> Note that randomization is not available when a target interrupt rate
> (freq) is enabled.
>
> The last used period can be collected using the PERF_SAMPLE_PERIOD flag
> in sample_type.
>
> The patch has been tested on X86. There is also code for PowerPC but
> I could not test it.
I don't thikn we need to touch the arch code, we didn't need to for
frequency driven sampling, so I don't see a reason to do so for
randomization either.
next prev parent reply other threads:[~2010-03-02 9:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-02 6:07 [PATCH] perf_events: add sampling period randomization support eranian
2010-03-02 6:20 ` David Miller
2010-03-02 8:21 ` Peter Zijlstra [this message]
2010-03-02 10:53 ` Robert Richter
2010-03-02 11:41 ` Peter Zijlstra
2010-03-02 14:18 ` Robert Richter
2010-03-02 13:10 ` Frederic Weisbecker
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=1267518088.25158.0.camel@laptop \
--to=peterz@infradead.org \
--cc=eranian@gmail.com \
--cc=eranian@google.com \
--cc=fweisbec@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=paulus@samba.org \
--cc=perfmon2-devel@lists.sf.net \
--cc=robert.richter@amd.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.