From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754148Ab1I1NYF (ORCPT ); Wed, 28 Sep 2011 09:24:05 -0400 Received: from casper.infradead.org ([85.118.1.10]:46570 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753079Ab1I1NYC convert rfc822-to-8bit (ORCPT ); Wed, 28 Sep 2011 09:24:02 -0400 Subject: Re: [RFC] Introduce greedy hrtimer walk on idle From: Peter Zijlstra To: Venki Pallipadi Cc: Thomas Gleixner , Ingo Molnar , Arjan van de Ven , Suresh Siddha , linux-kernel@vger.kernel.org Date: Wed, 28 Sep 2011 15:23:23 +0200 In-Reply-To: References: <1316804080-6396-1-git-send-email-venki@google.com> <1316808181.9084.49.camel@twins> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.0.3- Message-ID: <1317216203.24040.18.camel@twins> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2011-09-23 at 16:47 -0700, Venki Pallipadi wrote: > On Fri, Sep 23, 2011 at 1:03 PM, Peter Zijlstra wrote: > > On Fri, 2011-09-23 at 11:54 -0700, Venkatesh Pallipadi wrote: > >> Comments? > > > > Looks to be a possible IRQ latency issue as well, that can be a lot of > > timers to run.. > > > > We could add some rate limit on how many timers we service this way > and/or interrupt/disable-enable in the inner loop. > But, this would be a problem with current hrtimer as well. When > sched_tick timer is not around, we may end up servicing lot of timers > depending on number of them and slack. No? Right, still something to consider. We might just have to push down on slack for -rt or so when it becomes a problem.