From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: kvm guest: hrtimer: interrupt too slow Date: Mon, 05 Oct 2009 13:31:41 +0400 Message-ID: <4AC9BCFD.1040502@msgid.tls.msk.ru> References: <4AC207B1.7020901@msgid.tls.msk.ru> <20091003231205.GA15015@amt.cnet> <4AC88E7E.8050909@msgid.tls.msk.ru> <20091005005011.GA2939@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm , Frederic Weisbecker , Ingo Molnar To: Marcelo Tosatti Return-path: Received: from isrv.corpit.ru ([81.13.33.159]:37999 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753440AbZJEJcT (ORCPT ); Mon, 5 Oct 2009 05:32:19 -0400 In-Reply-To: <20091005005011.GA2939@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: Marcelo Tosatti wrote: [] > You should see min_delta_ns increase to a much smaller value, hopefully in > the 2000-10000 range. That's what I see: Oct 4 16:13:09 paltus kernel: [boot] Oct 5 12:35:51 paltus kernel: hrtimer: interrupt too slow, forcing clock min delta to 1500 ns Oct 5 12:47:29 paltus kernel: hrtimer: interrupt too slow, forcing clock min delta to 2250 ns I tried to stress-load the machine yesterday (Oct-4), including massive network usage (I think it's the network that triggers the issue most reliable), but wasn't able to trigger it. Today, at Monday, at normal system load, it triggered "by its own", increasing min_delta to 50% as in the patch. The system runs smoothly so far, but it's to be expected (till it increases min delta to some 10-digit number :). But I'm unsure still if that's the right approach... The root cause seems to be the problem, and this patch just tries to work around it in a better-than-before way. But it might be just me... ;) I'll continue watching it, since the machine(s) in question are important for us. Thanks! /mjt