From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758225Ab3LGE5i (ORCPT ); Fri, 6 Dec 2013 23:57:38 -0500 Received: from moutng.kundenserver.de ([212.227.17.10]:63115 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758126Ab3LGE5h convert rfc822-to-8bit (ORCPT ); Fri, 6 Dec 2013 23:57:37 -0500 Message-ID: <1386392252.5673.31.camel@marge.simpson.net> Subject: Re: [PATCH] Trace idle entry and exit times From: Mike Galbraith To: Andi Kleen Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Andi Kleen , lenb@kernel.org, tglx@linutronix.de, peterz@infradead.org Date: Sat, 07 Dec 2013 05:57:32 +0100 In-Reply-To: <1386377164-2223-1-git-send-email-andi@firstfloor.org> References: <1386377164-2223-1-git-send-email-andi@firstfloor.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 8BIT Mime-Version: 1.0 X-Provags-ID: V02:K0:buA2JQ3px43uW9GhtIt5KTyNRhwDOygrwYaksURfRkL nk9KicR6wlcQfEq8FaTGqjSvvOxyScTQeoBFRLAejnKCsyvsdf qBnLB3A0KR+zXD/gzf5ZFLMZFPoJnC2x7OpcEJ88I9S+F1gg6i uQXFkQI2P08QT3ZsqTvJ/FTtzwjx0lLDpofUChneWm7R7O3LNU s1TN7WdCjE8blHg+mXY6N1Nz19KtRGp4dMPMefmOIwtu4Kfs9j S7gLUd6lj8vXkl2EzTbyOatwRzh+M1zkVamR4rFM5yq/8MVGSi FF6ffS/q8fATKU1Z13+U9+3mSpIdivr34lSq3Rxvz7eLzXiTcR ct0KjBfgVzHgiY12ym+dDk2J9/UA4ZA33qHrmGRk3u5M3GxLVX lMdzHzjxHE3aQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2013-12-06 at 16:46 -0800, Andi Kleen wrote: > From: Andi Kleen > > This patch creates 4 new trace points: one at the beginning of idle, > one before entering mwait, one after exiting mwait, and one after > finishing the idle code. This is useful to trace down any > additional latencies caused by the ever-growing idle code. > > Idle latencies are a common source of performance problems, so it's > important to be able to measure them. You mean stuff like.. oh, say 60 cores doing zero work every 12ms munching ~20% cpu? - 97.57% [kernel] [k] _raw_spin_lock_irqsave ▒ - _raw_spin_lock_irqsave ▒ - 97.02% clockevents_notify ◆ intel_idle ▒ cpuidle_idle_call ▒ cpu_idle ▒ - 2.97% tick_broadcast_oneshot_control ▒ tick_notify ▒ notifier_call_chain ▒ clockevents_notify ▒ intel_idle ▒ cpuidle_idle_call ▒ cpu_idle C2 is super green, it's hug'n the sh*t outta them trees :) -Mike