Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752787Ab0DVG0M (ORCPT ); Thu, 22 Apr 2010 02:26:12 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.145]:56593 "EHLO e5.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751679Ab0DVG0K (ORCPT ); Thu, 22 Apr 2010 02:26:10 -0400 Message-ID: <4BCFEBFF.4090505@us.ibm.com> Date: Wed, 21 Apr 2010 23:26:07 -0700 From: Darren Hart User-Agent: Thunderbird 2.0.0.24 (X11/20100411) MIME-Version: 1.0 To: "lkml, " CC: Peter Zijlstra , Ingo Molnar Subject: Lockdep usage Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2146 Lines: 48 I'm having some trouble with lockstat. I've enabled CONFIG_LOCK_STATS and then run the following commands to collect the lock statistics for the futex_lock test case. I expect this test case to generate a fair amount of contention on the futex hash bucket locks, but they don't show up in the stats (in fact, nothing shows up in the stats). I have seen much longer lock_stat files when I forgot to clear them before the test, but no hb locks showed up there either. Is my usage below incorrect? Do I have to somehow annotate the hb->lock in order for lockstat to track it? This is as of: commit a3d3203e4bb40f253b1541e310dc0f9305be7c84 Merge: f937331... ec28dcc... Author: Linus Torvalds Date: Sun Mar 14 20:29:21 2010 -0700 # echo 0 > /proc/lock_stat; echo 1 > /proc/sys/kernel/lock_stat; ./futex_lock -i10000000 -p1000 -d20; cat /proc/lock_stat > lock.lockstat; echo 0 > /proc/sys/kernel/lock_stat futex_lock: Measure FUTEX_LOCK operations per second Arguments: iterations=10000000 threads=256 adaptive=no period=1000 duty-cycle=20% Result: 731 Kiter/s # cat lock.lockstat lock_stat version 0.3 *WARNING* lock debugging disabled!! - possibly due to a lockdep warning ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # Thanks, -- Darren Hart IBM Linux Technology Center Real-Time Linux Team -- 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/