From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 18 Nov 2002 13:45:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 18 Nov 2002 13:45:42 -0500 Received: from packet.digeo.com ([12.110.80.53]:34504 "EHLO packet.digeo.com") by vger.kernel.org with ESMTP id ; Mon, 18 Nov 2002 13:45:41 -0500 Message-ID: <3DD936F4.EDA4968A@digeo.com> Date: Mon, 18 Nov 2002 10:52:36 -0800 From: Andrew Morton X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.5.46 i686) X-Accept-Language: en MIME-Version: 1.0 To: Davide Libenzi CC: Dave Hansen , William Lee Irwin III , "Martin J. Bligh" , Linux Kernel Mailing List , Ingo Molnar , Robert Love , riel@surriel.com Subject: Re: unusual scheduling performance References: <3DD92E92.EEB9ECD6@digeo.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 18 Nov 2002 18:52:36.0177 (UTC) FILETIME=[A907F410:01C28F33] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Davide Libenzi wrote: > > On Mon, 18 Nov 2002, Andrew Morton wrote: > > > Dave Hansen wrote: > > > > > > ... > > > rwsem_down_write_failed: 133 133 > > > > Possible culprit. > > > > Please stick a dump_stack() in rwsem_down_write_failed(), and add the below. > > Suggest you stick with 2.5.47 to diagnose this. The loss of kksymoops > > is a pain. > > > > > > fs/eventpoll.c | 2 ++ > > 1 files changed, 2 insertions(+) > > > > --- 25/fs/eventpoll.c~hey Mon Nov 18 10:13:40 2002 > > +++ 25-akpm/fs/eventpoll.c Mon Nov 18 10:14:01 2002 > > @@ -328,6 +328,8 @@ void eventpoll_release(struct file *file > > if (list_empty(lsthead)) > > return; > > > > + printk("hey!\n"); > > + > > Andrew, if you don't use epoll there's no way you get there. Yup. That was a random stab based on recently-added down_write() calls. However the down_write isn't there in 2.5.47 so that's a false lead. We'll need that dump_stack() output. Here's Dave's profile. ep_notify_file_close() makes a small appearance. The change you made to 2.5.48 will wipe that out. Neat. 0.058% 78 locks_remove_flock 0.062% 82 page_cache_readahead 0.062% 83 __generic_file_aio_read 0.065% 86 file_move 0.065% 87 dget_locked 0.066% 88 proc_pid_stat 0.067% 89 ep_notify_file_close 0.068% 91 get_pid_list 0.070% 93 update_atime 0.079% 105 get_unused_fd 0.085% 113 fget 0.090% 120 dput 0.091% 121 get_empty_filp 0.097% 129 system_call 0.100% 133 rwsem_down_write_failed 0.124% 164 vfs_follow_link 0.171% 227 file_read_actor 0.182% 241 __fput 0.221% 293 radix_tree_lookup 0.232% 307 atomic_dec_and_lock 0.250% 331 .text.lock.dec_and_lock 0.282% 374 try_to_wake_up 0.301% 398 kmap_atomic 0.309% 409 kunmap_atomic 0.326% 431 vfs_read 0.364% 482 .text.lock.namei 0.391% 518 __d_lookup 0.537% 710 link_path_walk 0.801% 1060 schedule 1.396% 1846 do_generic_mapping_read 25.275% 33416 poll_idle 66.319% 87678 __copy_to_user 100.000% 132206 total