Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752511AbaLSUqS (ORCPT ); Fri, 19 Dec 2014 15:46:18 -0500 Received: from mail-qa0-f43.google.com ([209.85.216.43]:46643 "EHLO mail-qa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751892AbaLSUqR (ORCPT ); Fri, 19 Dec 2014 15:46:17 -0500 MIME-Version: 1.0 In-Reply-To: References: <20141218051327.GA31988@redhat.com> <1418918059.17358.6@mail.thefacebook.com> <20141218161230.GA6042@redhat.com> <20141219024549.GB1671@redhat.com> <20141219035859.GA20022@redhat.com> <20141219040308.GB20022@redhat.com> <20141219145528.GC13404@redhat.com> Date: Fri, 19 Dec 2014 12:46:16 -0800 X-Google-Sender-Auth: You7DKQwRN81s16e-dxw32tvhMY Message-ID: Subject: Re: frequent lockups in 3.18rc4 From: Linus Torvalds To: Dave Jones , Chris Mason , Mike Galbraith , Ingo Molnar , Peter Zijlstra , =?UTF-8?Q?D=C3=A2niel_Fraga?= , Sasha Levin , "Paul E. McKenney" , Linux Kernel Mailing List , Suresh Siddha , Oleg Nesterov , Peter Anvin Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 19, 2014 at 11:51 AM, Linus Torvalds wrote: > > I do note that we depend on the "new mwait" semantics where we do > mwait with interrupts disabled and a non-zero RCX value. Are there > possibly even any known CPU errata in that area? Not that it sounds > likely, but still.. Remind me what CPU you have in that machine again? The %rax value for the mwait cases in question seems to be 0x32, which is either C7s-HSW or C7s-BDW, and in both cases has the "TLB flushed" flag set. I'm pretty sure you have a Haswell, I'm just checking. Which model? I'm assuming it's family 6, model 60, stepping 3? I found you mentioning i5-4670T in a perf thread.. That the one? Anyway, I don't actually believe in any CPU bugs, but you could try "intel_idle.max_cstate=0" and see if that makes any difference, for example. Or perhaps just "intel_idle.max_cstate=1", which leaves intel_idle active, but gets rid of the deeper sleep states (that incidentally also play games with leave_mm() etc) Linus -- 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/