Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 31 Dec 2000 05:13:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 31 Dec 2000 05:12:57 -0500 Received: from www.wen-online.de ([212.223.88.39]:17683 "EHLO wen-online.de") by vger.kernel.org with ESMTP id ; Sun, 31 Dec 2000 05:12:54 -0500 Date: Sun, 31 Dec 2000 10:42:26 +0100 (CET) From: Mike Galbraith To: linux-kernel Subject: scheduling problem test13-pre7 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, While running iozone, I notice severe stalls of vmstat output despite vmstat running SCHED_RR and mlockall(). With IKD, I ran a million line ktrace of such a stall, and find no occurance of vmstat's pid. (trace covers a ~full second of kernel time) The only user process which was scheduled during this second was iozone itself (p262). I have seen such stalls last for ~5 seconds. %TOT_TIME TOT_USECS AVG/CALL NCALLS KADDR FUNCTION PID 0.0002% 2.15 2.15 1 c01077db __switch_to p4 0.0025% 24.18 2.69 9 c01077db __switch_to p262 0.0043% 41.91 0.86 49 c01077db __switch_to p0 0.0049% 47.54 2.97 16 c01077db __switch_to p3 0.0107% 102.83 1.80 57 c01077db __switch_to p6 Tail end of profile of this trace by pid: %TOT_TIME TOT_USECS AVG/CALL NCALLS KADDR FUNCTION PID 0.2485% 2394.91 1.22 1964 c0108fea ret_from_sys_call p262 0.2496% 2405.70 0.61 3925 c0134f8b get_hash_table p262 0.2555% 2462.40 0.31 7854 c0135052 buffer_insert_inode_queue p262 0.2731% 2632.40 0.65 4029 c01a9bc7 ide_do_request p6 0.3339% 3218.32 0.85 3788 c012bdd0 kmem_cache_alloc p262 0.3899% 3757.91 0.18 21110 c012f1ee nr_free_pages p262 0.4086% 3937.88 0.50 7848 c013573f getblk p262 0.4385% 4225.65 0.32 13255 c011612a wake_up_process p262 0.5245% 5055.25 0.24 21110 c012f23a nr_inactive_clean_pages p262 0.5468% 5269.94 9.38 562 c012d017 swap_out p4 0.7403% 7134.44 1.76 4046 c018a907 elevator_linus_merge p6 2.8165% 27144.72 0.54 50589 c0137527 try_to_free_buffers p4 3.1803% 30650.25 43.05 712 c0111caa apm_bios_call_simple p3 3.8435% 37041.89 0.20 185504 c012cbf7 try_to_swap_out p4 5.0470% 48641.41 0.95 51157 c012f179 __free_pages p4 9.8731% 95152.96 0.54 177443 c0137527 try_to_free_buffers p6 10.7010% 103132.39 26.28 3925 c020bb80 __generic_copy_from_user p262 17.5982% 169604.69 0.94 180429 c012f179 __free_pages p6 33.8960% 326677.23 2916.76 112 c0107171 default_idle p0 1048352 entries; 963762.98 total usecs. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/