Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754670AbaAVSfm (ORCPT ); Wed, 22 Jan 2014 13:35:42 -0500 Received: from ud10.udmedia.de ([194.117.254.50]:58961 "EHLO mail.ud10.udmedia.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752545AbaAVSfk (ORCPT ); Wed, 22 Jan 2014 13:35:40 -0500 Date: Wed, 22 Jan 2014 19:35:38 +0100 From: Markus Trippelsdorf To: Sasha Levin Cc: Peter Zijlstra , Arjan van de Ven , lenb@kernel.org, rjw@rjwysocki.net, Eliezer Tamir , rui.zhang@intel.com, jacob.jun.pan@linux.intel.com, Mike Galbraith , Ingo Molnar , hpa@zytor.com, paulmck@linux.vnet.ibm.com, Thomas Gleixner , John Stultz , Andy Lutomirski , linux-kernel@vger.kernel.org, dyoung@redhat.com Subject: Re: [PATCH 13/15] sched: Use a static_key for sched_clock_stable Message-ID: <20140122183538.GA389@x4> References: <20131212140835.729222186@infradead.org> <20131212141655.362219382@infradead.org> <52DEF495.2020304@oracle.com> <20140122104532.GJ31570@twins.programming.kicks-ass.net> <20140122120048.GB389@x4> <20140122120757.GL31570@twins.programming.kicks-ass.net> <20140122122609.GA392@x4> <20140122123022.GN31570@twins.programming.kicks-ass.net> <20140122131456.GA389@x4> <52DFD50E.800@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52DFD50E.800@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014.01.22 at 09:26 -0500, Sasha Levin wrote: > On 01/22/2014 08:14 AM, Markus Trippelsdorf wrote: > > On 2014.01.22 at 13:30 +0100, Peter Zijlstra wrote: > >> >On Wed, Jan 22, 2014 at 01:26:09PM +0100, Markus Trippelsdorf wrote: > >>> > >On 2014.01.22 at 13:07 +0100, Peter Zijlstra wrote: > >>>> > > >On Wed, Jan 22, 2014 at 01:00:48PM +0100, Markus Trippelsdorf wrote: > >>>>> > > > >FYI it happens on real hardware on my machine: > >>>>> > > > >... > >>>>> > > > >[ 0.000000] Hierarchical RCU implementation. > >>>>> > > > >[ 0.000000] NR_IRQS:4352 nr_irqs:712 16 > >>>>> > > > >[ 0.000000] spurious 8259A interrupt: IRQ7. > >>>>> > > > >[ 0.000000] Console: colour VGA+ 80x25 > >>>>> > > > >[ 0.000000] console [tty0] enabled > >>>>> > > > >[ 0.000000] hpet clockevent registered > >>>>> > > > >[ 0.000000] tsc: Fast TSC calibration using PIT > >>>>> > > > >[ 0.003333] tsc: Detected 3210.681 MHz processor > >>>>> > > > >[ 60.375238] Calibrating delay loop (skipped), value calculated using timer frequency.. 6423.91 BogoMIPS (lpj=10702270) > >>>>> > > > >[ 60.375240] pid_max: default: 32768 minimum: 301 > >>>>> > > > >[ 60.375259] Mount-cache hash table entries: 256 > >>>>> > > > >[ 60.375373] tseg: 0000000000 > >>>>> > > > >[ 60.375377] CPU: Physical Processor ID: 0 > >>>>> > > > >[ 60.375377] CPU: Processor Core ID: 0 > >>>>> > > > >[ 60.375378] mce: CPU supports 6 MCE banks > >>>>> > > > >[ 60.375382] LVT offset 0 assigned for vector 0xf9 > >>>>> > > > >[ 60.375384] process: using AMD E400 aware idle routine > >>>>> > > > >[ 60.375386] Last level iTLB entries: 4KB 512, 2MB 16, 4MB 8 > >>>> > > > > >>>> > > >Should have always happened like that I think. From the log it looks > >>>> > > >like the moment we switch from jiffies to actual TSC in > >>>> > > >arch/x86/kernel/tsc.c:sched_clock(). > >>>> > > > > >>>> > > >I don't think I changed the logic there, just switched from a condition > >>>> > > >to a jump_label. > >>> > > > >>> > >Well, v3.13 was fine. So it's definitely a regression. But it may be > >>> > >another issue. I will try to bisect later. > >> > > >> >OK, weird, I'll see if I can spot anything. > > Unfortunately the issue is unbisectable (but the remaining commits are > > all yours): > > I've actually bisected it previously by fixing the build errors manually, and that took me > to this patch you see in the subject line :) But this is a different issue. I've bisected it to: commit 20d1c86a57762f0a33a78988e3fc8818316badd4 Author: Peter Zijlstra Date: Fri Nov 29 15:40:29 2013 +0100 sched/clock, x86: Rewrite cyc2ns() to avoid the need to disable IRQs Reverting the commit "fixes" the issue: ... [ 0.000000] Hierarchical RCU implementation. [ 0.000000] NR_IRQS:4352 nr_irqs:712 16 [ 0.000000] spurious 8259A interrupt: IRQ7. [ 0.000000] Console: colour VGA+ 80x25 [ 0.000000] console [tty0] enabled [ 0.000000] hpet clockevent registered [ 0.000000] tsc: Fast TSC calibration using PIT [ 0.003333] tsc: Detected 3211.075 MHz processor [ 0.000006] Calibrating delay loop (skipped), value calculated using timer frequency.. 6424.73 BogoMIPS (lpj=10703583) [ 0.000007] pid_max: default: 32768 minimum: 301 [ 0.000026] Mount-cache hash table entries: 256 [ 0.000139] tseg: 0000000000 [ 0.000143] CPU: Physical Processor ID: 0 [ 0.000144] CPU: Processor Core ID: 0 [ 0.000145] mce: CPU supports 6 MCE banks [ 0.000148] LVT offset 0 assigned for vector 0xf9 [ 0.000151] process: using AMD E400 aware idle routine [ 0.000152] Last level iTLB entries: 4KB 512, 2MB 16, 4MB 8 ... -- Markus -- 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/