Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263740AbUFXJ1o (ORCPT ); Thu, 24 Jun 2004 05:27:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264048AbUFXJ1o (ORCPT ); Thu, 24 Jun 2004 05:27:44 -0400 Received: from smtp106.mail.sc5.yahoo.com ([66.163.169.226]:375 "HELO smtp106.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S263740AbUFXJ1l (ORCPT ); Thu, 24 Jun 2004 05:27:41 -0400 Message-ID: <40DA9E89.9020801@yahoo.com.au> Date: Thu, 24 Jun 2004 19:27:37 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040401 Debian/1.6-4 X-Accept-Language: en MIME-Version: 1.0 To: Yusuf Goolamabbas CC: linux-kernel@vger.kernel.org Subject: Re: finish_task_switch high in profiles in 2.6.7 References: <20040624091548.GA8264@outblaze.com> In-Reply-To: <20040624091548.GA8264@outblaze.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3581 Lines: 71 Yusuf Goolamabbas wrote: > Hi, I have a fairly busy mailserver which also has a simple iptables > ruleset (blocking some IP's) running 2.6.7 with the deadline i/o > scheduler. vmstat was reporting that system time was around 80%. I did > the following > > readprofile -r ; sleep 240 ; readprofile -n -m /boot/System.map-`uname > -r` | sort -rn -k 1,1 | head -22 > > 48036 total 0.2274 > 9684 finish_task_switch 80.0331 > 6992 default_idle 158.9091 > 6335 __wake_up 87.9861 > 5671 remove_wait_queue 76.6351 > 4150 add_wait_queue 59.2857 > 2459 sysenter_past_esp 21.7611 > 1304 find_get_page 21.0323 > 1160 __mod_timer 4.1281 > 938 do_gettimeofday 5.0430 > 756 del_timer_sync 2.4787 > 753 del_timer 7.1714 > 599 handle_IRQ_event 5.9900 > 570 do_page_fault 0.4612 > 485 __do_softirq 2.8529 > 476 do_sigaction 0.9136 > 469 do_getitimer 1.7055 > 464 do_setitimer 0.9768 > 392 get_offset_tsc 17.0435 > 340 current_kernel_time 4.9275 > 293 in_group_p 2.4417 > 272 eligible_child 1.4093 > > On a 2.6.5 box with a similar workload, the profile is as follows > > 131202 total 0.3704 > 42080 fget 667.9365 > 12868 schedule 8.1084 > 11231 default_idle 255.2500 > 9157 fput 436.0476 > 6642 remove_wait_queue 89.7568 > 6076 __wake_up 93.4769 > 5056 page_remove_rmap 13.4111 > 4144 add_wait_queue 59.2000 > 2255 fget_light 17.4806 > 2176 sysenter_past_esp 19.2566 > 1271 kfree 11.6606 > 1148 kmem_cache_alloc 14.9091 > 934 __kmalloc 6.6714 > 890 __mod_timer 3.1673 > 768 del_timer_sync 2.9538 > 717 buffered_rmqueue 1.5621 > 715 kmem_cache_free 8.2184 > 613 free_hot_cold_page 2.4618 > 612 del_timer 5.8286 > 588 __find_get_block 3.0466 > 588 do_page_fault 0.4757 > > I am trying to determine where the system time is going and don't have > much zen to begin with. Any assistance would be appreciated ? > Is it an SMP system? What sort of workload is it? Does it use threads? Check vmstat to see how much context switching is going on with each kernel. Thanks. - 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/