Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757275AbXJaJ7S (ORCPT ); Wed, 31 Oct 2007 05:59:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755390AbXJaJ7H (ORCPT ); Wed, 31 Oct 2007 05:59:07 -0400 Received: from mga05.intel.com ([192.55.52.89]:26586 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752539AbXJaJ7F (ORCPT ); Wed, 31 Oct 2007 05:59:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.21,351,1188802800"; d="scan'208";a="364131025" Subject: Re: aim7 -30% regression in 2.6.24-rc1 From: "Zhang, Yanmin" To: Ingo Molnar Cc: LKML , Peter Zijlstra In-Reply-To: <1193733390.3019.210.camel@ymzhang> References: <1193391787.3019.174.camel@ymzhang> <20071026112307.GA30406@elte.hu> <1193624538.3019.189.camel@ymzhang> <1193650626.3019.198.camel@ymzhang> <1193710325.3019.203.camel@ymzhang> <20071030072658.GB20372@elte.hu> <1193733390.3019.210.camel@ymzhang> Content-Type: text/plain; charset=utf-8 Date: Wed, 31 Oct 2007 17:57:48 +0800 Message-Id: <1193824668.3019.236.camel@ymzhang> Mime-Version: 1.0 X-Mailer: Evolution 2.9.2 (2.9.2-2.fc7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6013 Lines: 124 On Tue, 2007-10-30 at 16:36 +0800, Zhang, Yanmin wrote: > On Tue, 2007-10-30 at 08:26 +0100, Ingo Molnar wrote: > > * Zhang, Yanmin wrote: > > > > > sub-bisecting captured patch > > > 38ad464d410dadceda1563f36bdb0be7fe4c8938(sched: uniform tunings) > > > caused 20% regression of aim7. > > > > > > The last 10% should be also related to sched parameters, such like > > > sysctl_sched_min_granularity. > > > > ah, interesting. Since you have CONFIG_SCHED_DEBUG enabled, could you > > please try to figure out what the best value for > > /proc/sys/kernel_sched_latency, /proc/sys/kernel_sched_nr_latency and > > /proc/sys/kernel_sched_min_granularity is? > > > > there's a tuning constraint for kernel_sched_nr_latency: > > > > - kernel_sched_nr_latency should always be set to > > kernel_sched_latency/kernel_sched_min_granularity. (it's not a free > > tunable) > > > > i suspect a good approach would be to double the value of > > kernel_sched_latency and kernel_sched_nr_latency in each tuning > > iteration, while keeping kernel_sched_min_granularity unchanged. That > > will excercise the tuning values of the 2.6.23 kernel as well. > I followed your idea to test 2.6.24-rc1. The improvement is slow. > When sched_nr_latency=2560 and sched_latency_ns=640000000, the performance > is still about 15% less than 2.6.23. I got the aim7 30% regression on my new upgraded stoakley machine. I found this mahcine is slower than the old one. Maybe BIOS has issues, or memeory(Might not be dual-channel?) is slow. So I retested it on the old machine and found on the old stoakley machine, the regression is about 6%, quite similiar to the regression on tigerton machine. By sched_nr_latency=640 and sched_latency_ns=640000000 on the old stoakley machine, the regression becomes about 2%. Other latency has more regression. On my tulsa machine, by sched_nr_latency=640 and sched_latency_ns=640000000, the regression becomes less than 1% (The original regression is about 20%). When I ran a bad script to change the values of sched_nr_latency and sched_latency_ns, I hit OOPS on my tulsa machine. Below is the log. It looks like sched_nr_latency becomes 0. *******************Log************************************ divide error: 0000 [1] SMP CPU 1 Modules linked in: megaraid_mbox megaraid_mm Pid: 7326, comm: sh Not tainted 2.6.24-rc1 #2 RIP: 0010:[] [] __sched_period+0x22/0x2e RSP: 0018:ffff810105909e38 EFLAGS: 00010046 RAX: 000000005a000000 RBX: 0000000000000000 RCX: 000000002d000000 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002 RBP: ffff810105909e40 R08: ffff810103bfed50 R09: 00000000ffffffff R10: 0000000000000038 R11: 0000000000000296 R12: ffff810100d6db40 R13: ffff8101058c4148 R14: 0000000000000001 R15: ffff810104c34088 FS: 00002b851bc59f50(0000) GS:ffff810100cb1b40(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00000000006c64d8 CR3: 000000010752c000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process sh (pid: 7326, threadinfo ffff810105908000, task ffff810104c34040) Stack: 0000000000000800 ffff810105909e58 ffffffff8022c2db 00000000079d292b ffff810105909e88 ffffffff8022c36e ffff810100d6db40 ffff8101058c4148 ffff8101058c4100 0000000000000001 ffff810105909ec8 ffffffff80232d0a Call Trace: [] __sched_vslice+0x10/0x1d [] place_entity+0x86/0xc3 [] task_new_fair+0x48/0xa5 [] system_call+0x7e/0x83 [] wake_up_new_task+0x70/0xa4 [] do_fork+0x137/0x204 [] vfs_write+0x121/0x136 [] recalc_sigpending+0xe/0x25 [] sigprocmask+0x9e/0xc0 [] ptregscall_common+0x67/0xb0 Code: 48 f7 f3 48 89 c1 5b c9 48 89 c8 c3 55 48 89 e5 53 48 89 fb RIP [] __sched_period+0x22/0x2e RSP divide error: 0000 [2] SMP CPU 0 Modules linked in: megaraid_mbox megaraid_mm Pid: 3674, comm: automount Tainted: G D 2.6.24-rc1 #2 RIP: 0010:[] [] __sched_period+0x22/0x2e RSP: 0018:ffff81010690de38 EFLAGS: 00010046 RAX: 000000005a000000 RBX: 0000000000000000 RCX: 000000002d000000 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002 RBP: ffff81010690de40 R08: ffff81010690c000 R09: 00000000ffffffff R10: 0000000000000038 R11: ffff810104007040 R12: ffff810001033880 R13: ffff810100f2a828 R14: 0000000000000001 R15: ffff810104007088 FS: 0000000040021950(0063) GS:ffffffff8074e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00002b6cc4245000 CR3: 0000000105972000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process automount (pid: 3674, threadinfo ffff81010690c000, task ffff810104007040) Stack: 0000000000000800 ffff81010690de58 ffffffff8022c2db 000000057aef240d ffff81010690de88 ffffffff8022c36e ffff810001033880 ffff810100f2a828 ffff810100f2a7e0 0000000000000000 ffff81010690dec8 ffffffff80232d0a Call Trace: [] __sched_vslice+0x10/0x1d [] place_entity+0x86/0xc3 [] task_new_fair+0x48/0xa5 [] system_call+0x7e/0x83 [] wake_up_new_task+0x70/0xa4 [] do_fork+0x137/0x204 [] ptregscall_common+0x67/0xb0 Code: 48 f7 f3 48 89 c1 5b c9 48 89 c8 c3 55 48 89 e5 53 48 89 fb RIP [] __sched_period+0x22/0x2e RSP - 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/