From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751252AbdJBOOC (ORCPT ); Mon, 2 Oct 2017 10:14:02 -0400 Received: from foss.arm.com ([217.140.101.70]:37574 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751065AbdJBOOA (ORCPT ); Mon, 2 Oct 2017 10:14:00 -0400 Date: Mon, 2 Oct 2017 15:14:00 +0100 From: Will Deacon To: qiaozhou Cc: Vikram Mulukutla , Thomas Gleixner , John Stultz , sboyd@codeaurora.org, LKML , Wang Wilbur , Marc Zyngier , Peter Zijlstra , linux-kernel-owner@vger.kernel.org, sudeep.holla@arm.com Subject: Re: [Question]: try to fix contention between expire_timers and try_to_del_timer_sync Message-ID: <20171002141400.GB12847@arm.com> References: <20170728092831.GA24839@arm.com> <2aa9684cf9c889ee9fdc8550b4388af6@codeaurora.org> <20170731131321.GB1737@arm.com> <20170815184039.GE10801@arm.com> <9f86bd426bbaede9de6d38cb047bd6fa@codeaurora.org> <8817730a-9581-240c-8de0-e6c96c20e9ec@asrmicro.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8817730a-9581-240c-8de0-e6c96c20e9ec@asrmicro.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Qiao, On Mon, Sep 25, 2017 at 07:02:03PM +0800, qiaozhou wrote: > Will this bodging patch be merged? It can solve the livelock issue on arm64 > platforms(at least improve a lot). Whilst it seemed to help in some cases, I'm not keen to merge it until we've identified a sensible way to parameterise the threshold and also explain why it doens't appear to help at all on some platforms. I guess I could respin a version that takes the threshold on the cmdline and also checks to see that the event stream is enabled, since that might help with further benchmarking. Would that be useful? Will