From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757032Ab3BVKbx (ORCPT ); Fri, 22 Feb 2013 05:31:53 -0500 Received: from service87.mimecast.com ([91.220.42.44]:59646 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754440Ab3BVKbv convert rfc822-to-8bit (ORCPT ); Fri, 22 Feb 2013 05:31:51 -0500 Date: Fri, 22 Feb 2013 10:31:49 +0000 From: Lorenzo Pieralisi To: Thomas Gleixner Cc: Santosh Shilimkar , Jason Liu , LKML , "linux-arm-kernel@lists.infradead.org" Subject: Re: too many timer retries happen when do local timer swtich with broadcast timer Message-ID: <20130222103149.GC12140@e102568-lin.cambridge.arm.com> References: <51263975.20906@ti.com> <5127436E.4040100@ti.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-OriginalArrivalTime: 22 Feb 2013 10:31:49.0843 (UTC) FILETIME=[D2ADFA30:01CE10E7] X-MC-Unique: 113022210315000201 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 22, 2013 at 10:24:00AM +0000, Thomas Gleixner wrote: > On Fri, 22 Feb 2013, Santosh Shilimkar wrote: > > BTW, Lorenzo off-list mentioned to me about warning in boot-up > > which I missed while testing your patch. It will take bit more > > time for me to look into it and hence thought of reporting it. > > > > [ 2.186126] ------------[ cut here ]------------ > > [ 2.190979] WARNING: at kernel/time/tick-broadcast.c:501 > > tick_broadcast_oneshot_control+0x1c0/0x21c() > > Which one is that? tick_broadcast_pending or tick_force_broadcast_mask ? It is the tick_force_broadcast_mask and I think that's because on all systems we are testing, the broadcast timer IRQ is a thundering herd, all CPUs get out of idle at once and try to get out of broadcast mode at more or less the same time. Lorenzo