From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755578Ab0CKJtV (ORCPT ); Thu, 11 Mar 2010 04:49:21 -0500 Received: from mail.gmx.net ([213.165.64.20]:51935 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755183Ab0CKJtT (ORCPT ); Thu, 11 Mar 2010 04:49:19 -0500 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1+wvIZiKxKwXKTE9oZxhjl8VKnkgQp2cxMDnbOC62 e0oOtd3jpJ98P6 Subject: [patch 0/12] sched: fastpath cycle recovery From: Mike Galbraith To: Peter Zijlstra Cc: Ingo Molnar , LKML Content-Type: text/plain Date: Thu, 11 Mar 2010 10:49:10 +0100 Message-Id: <1268300950.6785.27.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1.1 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 X-FuHaFi: 0.64000000000000001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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