From: Peter Zijlstra <peterz@infradead.org>
To: Benjamin Segall <bsegall@google.com>
Cc: Paul Turner <pjt@google.com>,
linux-kernel@vger.kernel.org, Venki Pallipadi <venki@google.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>,
Mike Galbraith <efault@gmx.de>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Ingo Molnar <mingo@elte.hu>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Morten Rasmussen <Morten.Rasmussen@arm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Subject: Re: [PATCH 14/16] sched: make __update_entity_runnable_avg() fast
Date: Tue, 10 Jul 2012 12:51:30 +0200 [thread overview]
Message-ID: <1341917490.3462.119.camel@twins> (raw)
In-Reply-To: <xm26fw90zo16.fsf@sword-of-the-dawn.mtv.corp.google.com>
On Mon, 2012-07-09 at 13:18 -0700, Benjamin Segall wrote:
> Correct, the sum is 1..n. The maximum was chosen as 516/46742 because
> that is the point when the approximation of loop + fixed point math
> being used reaches a maximum, even if the ideal y^n series would cap out
> slightly differently.
Can you run a simple kid like me through the math here.. it seems
strange that fixed point math would give a higher order term than the
regular case. And by such a wide margin as well, (516-320)/32 ~ 6, so
that's 1/64-th of the 320-th term.
next prev parent reply other threads:[~2012-07-10 10:51 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-28 2:24 [PATCH 00/16] Series short description Paul Turner
2012-06-28 2:24 ` [PATCH 07/16] sched: aggregate total task_group load Paul Turner
2012-06-28 2:24 ` [PATCH 06/16] sched: account for blocked load waking back up Paul Turner
2012-06-28 2:24 ` [PATCH 03/16] sched: aggregate load contributed by task entities on parenting cfs_rq Paul Turner
2012-06-28 6:33 ` Namhyung Kim
2012-07-04 15:28 ` Peter Zijlstra
2012-07-06 14:53 ` Peter Zijlstra
2012-07-09 9:15 ` Ingo Molnar
2012-06-28 2:24 ` [PATCH 05/16] sched: add an rq migration call-back to sched_class Paul Turner
2012-06-29 1:32 ` Namhyung Kim
2012-06-28 2:24 ` [PATCH 08/16] sched: compute load contribution by a group entity Paul Turner
2012-06-28 2:24 ` [PATCH 01/16] sched: track the runnable average on a per-task entitiy basis Paul Turner
2012-06-28 6:06 ` Namhyung Kim
2012-07-12 0:14 ` Paul Turner
2012-07-04 15:32 ` Peter Zijlstra
2012-07-12 0:12 ` Paul Turner
2012-06-28 2:24 ` [PATCH 09/16] sched: normalize tg load contributions against runnable time Paul Turner
2012-06-29 7:26 ` Namhyung Kim
2012-07-04 19:48 ` Peter Zijlstra
2012-07-06 11:52 ` Peter Zijlstra
2012-07-12 1:08 ` Andre Noll
2012-07-12 0:02 ` Paul Turner
2012-07-06 12:23 ` Peter Zijlstra
2012-06-28 2:24 ` [PATCH 02/16] sched: maintain per-rq runnable averages Paul Turner
2012-06-28 2:24 ` [PATCH 04/16] sched: maintain the load contribution of blocked entities Paul Turner
2012-06-29 1:27 ` Namhyung Kim
2012-06-28 2:24 ` [PATCH 10/16] sched: maintain runnable averages across throttled periods Paul Turner
2012-06-28 2:24 ` [PATCH 12/16] sched: refactor update_shares_cpu() -> update_blocked_avgs() Paul Turner
2012-06-29 7:28 ` Namhyung Kim
2012-07-12 0:03 ` Paul Turner
2012-07-05 11:58 ` Peter Zijlstra
2012-07-12 0:11 ` Paul Turner
2012-07-12 14:40 ` Peter Zijlstra
2012-06-28 2:24 ` [PATCH 15/16] sched: implement usage tracking Paul Turner
2012-06-28 2:24 ` [PATCH 11/16] sched: replace update_shares weight distribution with per-entity computation Paul Turner
2012-06-28 2:24 ` [PATCH 16/16] sched: introduce temporary FAIR_GROUP_SCHED dependency for load-tracking Paul Turner
2012-06-28 2:24 ` [PATCH 14/16] sched: make __update_entity_runnable_avg() fast Paul Turner
2012-07-04 15:41 ` Peter Zijlstra
2012-07-04 17:20 ` Peter Zijlstra
2012-07-09 20:18 ` Benjamin Segall
2012-07-10 10:51 ` Peter Zijlstra [this message]
2012-07-12 0:15 ` Paul Turner
2012-07-12 14:30 ` Peter Zijlstra
2012-07-04 16:51 ` Peter Zijlstra
2012-06-28 2:24 ` [PATCH 13/16] sched: update_cfs_shares at period edge Paul Turner
-- strict thread matches above, loose matches on Subject: below --
2012-08-23 14:14 [patch 00/16] sched: per-entity load-tracking pjt
2012-08-23 14:14 ` [patch 14/16] sched: make __update_entity_runnable_avg() fast pjt
2012-08-24 8:28 ` Namhyung Kim
2012-08-28 22:18 ` Paul Turner
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=1341917490.3462.119.camel@twins \
--to=peterz@infradead.org \
--cc=Morten.Rasmussen@arm.com \
--cc=bsegall@google.com \
--cc=efault@gmx.de \
--cc=kamalesh@linux.vnet.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=nikunj@linux.vnet.ibm.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=pjt@google.com \
--cc=svaidy@linux.vnet.ibm.com \
--cc=vatsa@in.ibm.com \
--cc=venki@google.com \
--cc=vincent.guittot@linaro.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