Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751288AbZGVOip (ORCPT ); Wed, 22 Jul 2009 10:38:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750998AbZGVOio (ORCPT ); Wed, 22 Jul 2009 10:38:44 -0400 Received: from www.tglx.de ([62.245.132.106]:46394 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750849AbZGVOio (ORCPT ); Wed, 22 Jul 2009 10:38:44 -0400 Date: Wed, 22 Jul 2009 16:38:18 +0200 (CEST) From: Thomas Gleixner To: Martin Schwidefsky cc: linux-kernel@vger.kernel.org, Ingo Molnar , john stultz , Venki Pallipadi Subject: Re: [RFC][PATCH] cache __next_timer_interrupt result In-Reply-To: <20090721202505.7d56a079@skybase> Message-ID: References: <20090721202505.7d56a079@skybase> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 854 Lines: 24 On Tue, 21 Jul 2009, Martin Schwidefsky wrote: > From: Martin Schwidefsky > > Each time a cpu goes to sleep on a NOHZ=y system the timer wheel is > searched for the next timer interrupt. It can take quite a few cycles > to find the next pending timer. This patch adds a field to tvec_base > that caches the result of __next_timer_interrupt. The hit ratio is > around 80% on my thinkpad under normal use, on a server I've seen Nice, I like it. > hit ratios from 5% to 95% dependent on the workload. Which workloads result in lower hit ratios ? Heavy networking ? Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/