From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261818AbULGOif (ORCPT ); Tue, 7 Dec 2004 09:38:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261819AbULGOif (ORCPT ); Tue, 7 Dec 2004 09:38:35 -0500 Received: from apollo.nbase.co.il ([194.90.137.2]:46343 "EHLO apollo.nbase.co.il") by vger.kernel.org with ESMTP id S261818AbULGOib (ORCPT ); Tue, 7 Dec 2004 09:38:31 -0500 Message-ID: <41B5C038.1090501@mrv.com> Date: Tue, 07 Dec 2004 16:37:44 +0200 From: emann@mrv.com (Eran Mann) User-Agent: Mozilla Thunderbird 1.0RC1 (X11/20041201) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ingo Molnar CC: linux-kernel@vger.kernel.org Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.32-2 References: <20041204175636.GA3115@elte.hu> In-Reply-To: <20041204175636.GA3115@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: ... > i've implemented the 'tracing follows the task' logic in the -32-2 > patch, available from the usual place: > > http://redhat.com/~mingo/realtime-preempt/ > > i've also added a CPU# field and i've reworked latency_trace format, to > make it more readable. Whenever preempt_wakeup_timing is enabled, > user-tracing will follow the traced task, if it's disabled then tracing > will stay on the CPU. No other changes. ... > Ingo On my machine, disabling CONFIG_LATENCY_TRACE causes the kernel to stop reporting preempt latencies. After # echo 1 > /proc/sys/kernel/preempt_max_latency /proc/sys/kernel/preempt_max_latency always shows 1 no matter what load is on the machine. I´ve seen this behavior since the first time I tried to disable CONFIG_LATENCY_TRACE, around V0.7.31.something. Below is the exact diff between the 2 configs (the one that shows latencies and the one that doesn´t). Note that the only intentional change is turning off CONFIG_LATENCY_TRACE. ======================================================= --- /tmp/config-2.6.10-rc2-mm3-V0.7.32-2.lat 2004-12-07 16:25:03.000000000 +0200 +++ /tmp/config-2.6.10-rc2-mm3-V0.7.32-2.no_lat 2004-12-07 11:06:19.000000000 +0200 @@ -1,7 +1,7 @@ # # Automatically generated make config: don't edit # Linux kernel version: 2.6.10-rc2-mm3-V0.7.32-2 -# Tue Dec 7 11:07:07 2004 +# Mon Dec 6 20:24:09 2004 # CONFIG_X86=y CONFIG_MMU=y @@ -137,6 +137,7 @@ CONFIG_MTRR=y # CONFIG_EFI is not set CONFIG_HAVE_DEC_LOCK=y +# CONFIG_REGPARM is not set # # Performance-monitoring counters support @@ -1711,12 +1712,12 @@ CONFIG_CRITICAL_IRQSOFF_TIMING=y CONFIG_CRITICAL_TIMING=y CONFIG_LATENCY_TIMING=y -CONFIG_LATENCY_TRACE=y -CONFIG_MCOUNT=y +# CONFIG_LATENCY_TRACE is not set # CONFIG_RT_DEADLOCK_DETECT is not set # CONFIG_DEBUG_KOBJECT is not set CONFIG_DEBUG_BUGVERBOSE=y # CONFIG_DEBUG_INFO is not set +CONFIG_USE_FRAME_POINTER=y CONFIG_FRAME_POINTER=y CONFIG_EARLY_PRINTK=y # CONFIG_DEBUG_STACKOVERFLOW is not set ======================================================= -- Eran Mann