Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756368AbaFWRQy (ORCPT ); Mon, 23 Jun 2014 13:16:54 -0400 Received: from e35.co.us.ibm.com ([32.97.110.153]:41057 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751926AbaFWRQw (ORCPT ); Mon, 23 Jun 2014 13:16:52 -0400 Date: Mon, 23 Jun 2014 10:16:44 -0700 From: "Paul E. McKenney" To: Dave Hansen Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, ak@linux.intel.com, cl@gentwo.org, umgwanakikbuti@gmail.com Subject: Re: [PATCH tip/core/rcu] Reduce overhead of cond_resched() checks for RCU Message-ID: <20140623171644.GH4603@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20140621025958.GA7185@linux.vnet.ibm.com> <53A85BF9.7030006@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53A85BF9.7030006@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14062317-6688-0000-0000-000002C3EF2E Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 23, 2014 at 09:55:21AM -0700, Dave Hansen wrote: > This still has a regression. Commit 1ed70de (from Paul's git tree), > gets a result of 52231880. If I back up two commits to v3.16-rc1 and > revert ac1bea85 (the original culprit) the result goes back up to 57308512. > > So something is still going on here. And commit 1ed70de is in fact the right one, so... The rcutree.jiffies_till_sched_qs boot/sysfs parameter controls how long RCU waits before asking for quiescent states. The default is currently HZ/20. Does increasing this parameter help? Easy for me to increase the default if it does. > I'll go back and compare the grace period ages to see if I can tell what > is going on. That would be very helpful, thank you! Thanx, Paul > -- > > root@bigbox:~/will-it-scale# ./open1_processes -t 160 -s30 > testcase:Separate file open/close > warmup > min:319787 max:386071 total:57464989 > min:307235 max:351905 total:53289241 > min:291765 max:342439 total:51364514 > min:297948 max:349214 total:52552745 > min:294950 max:340132 total:51586179 > min:290791 max:339958 total:50793238 > measurement > min:298851 max:346868 total:51951469 > min:292879 max:340704 total:50817269 > min:305768 max:347381 total:52655149 > min:301046 max:345616 total:52449584 > min:300428 max:345293 total:52021166 > min:293404 max:337973 total:51012206 > min:303569 max:348191 total:52713179 > min:305523 max:357448 total:53707053 > min:307040 max:356937 total:53271883 > min:302134 max:347923 total:52477496 > min:297823 max:340488 total:51884417 > min:286981 max:338246 total:50496850 > min:295920 max:349405 total:51792563 > min:302749 max:343780 total:52305074 > min:298497 max:345208 total:52035318 > min:291393 max:332195 total:50163093 > min:303561 max:353396 total:52983515 > min:301613 max:352988 total:53029200 > min:300693 max:343726 total:52057334 > min:296801 max:352408 total:52028824 > min:304834 max:358236 total:53526191 > min:297933 max:338351 total:51578481 > min:299571 max:341679 total:51817941 > min:308225 max:354075 total:53760098 > min:296262 max:346965 total:51856596 > min:309196 max:356432 total:53455141 > min:295604 max:341814 total:51449366 > min:296931 max:345961 total:52051944 > min:300533 max:350304 total:52652951 > min:299887 max:350764 total:52955064 > average:52231880 > root@bigbox:~/will-it-scale# uname -a > Linux bigbox 3.16.0-rc1-00002-g1ed70de #176 SMP Mon Jun 23 09:04:02 PDT > 2014 x86_64 x86_64 x86_64 GNU/Linux > > > root@bigbox:~/will-it-scale# ./open1_processes -t 160 -s 30 > testcase:Separate file open/close > warmup > min:346853 max:416035 total:62412724 > min:281766 max:344178 total:52207349 > min:311187 max:374918 total:57149451 > min:326309 max:391061 total:60200366 > min:310327 max:375619 total:56744357 > min:323336 max:393415 total:59619164 > measurement > min:323934 max:393718 total:59665843 > min:307247 max:368313 total:55681436 > min:318210 max:378048 total:57849321 > min:314494 max:383884 total:57741073 > min:316497 max:385223 total:58565045 > min:320490 max:397636 total:59003133 > min:318695 max:391712 total:57789360 > min:304368 max:378540 total:56412216 > min:314609 max:384462 total:58298008 > min:317235 max:384205 total:58812490 > min:323556 max:388014 total:59468492 > min:301011 max:362664 total:55381779 > min:301113 max:364712 total:55375445 > min:311730 max:369336 total:56640530 > min:316951 max:381341 total:58649244 > min:317077 max:383943 total:58132878 > min:316970 max:390127 total:59039489 > min:315895 max:375937 total:57404755 > min:295500 max:346523 total:53086962 > min:310882 max:371923 total:56612144 > min:321837 max:390544 total:59651640 > min:303481 max:368716 total:56135908 > min:306437 max:367658 total:56388659 > min:307343 max:373645 total:56893136 > min:298703 max:358090 total:54152268 > min:319162 max:386583 total:58999429 > min:304881 max:361968 total:55286607 > min:311034 max:381100 total:57846182 > min:312786 max:378270 total:57964383 > min:311740 max:367481 total:56327526 > average:57308512 > root@bigbox:~/will-it-scale# uname -a > Linux bigbox 3.16.0-rc1-dirty #177 SMP Mon Jun 23 09:13:59 PDT 2014 > x86_64 x86_64 x86_64 GNU/Linux > -- 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/