linux-kernel - [patch 0/12] sched: fastpath cycle recovery

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1268300950.6785.27.camel@marge.simson.net>
Date:	Thu, 11 Mar 2010 10:49:10 +0100
From:	Mike Galbraith <efault@....de>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	Ingo Molnar <mingo@...e.hu>, LKML <linux-kernel@...r.kernel.org>
Subject: [patch 0/12] sched: fastpath cycle recovery

Hi Peter,

The following patchlets take a pinned pipe-test context switch frequency
in tip from 663KHZ to 694KHZ, and an unpinned instance from 450KHz to
540KHz.  With these applied to tip.today, I have zero 31-12->today
regressions, and even some modest progressions.

The biggest difference is made by the first patch.  We have a problem
with nohz when waking cross-cpu, which given select_idle_sibling(), we
do quite a bit.  In testing netperf TCP_RR, hitting nohz code on every
micro-idle was eating ~10% of throughput, making cross-cpu wakeup a
loser.  These patchlets combined turned netperf TCP_RR cross-cpu vs
affine from big loser into a winner.

All of these are trivial, mostly axe murder, but cycles add up.

	-Mike

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/