From: James Cloos Subject: Re: [Regression] Filesystem I/O is CPU-bound in rc7 and rc8 Date: Wed, 17 Feb 2010 15:04:47 -0500 Message-ID: References: <20100215154516.GB11057@think> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, jfs-discussion@lists.sourceforge.net, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, Chris Mason To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <20100215154516.GB11057@think> (Chris Mason's message of "Mon, 15 Feb 2010 10:45:16 -0500") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: jfs-discussion-bounces@lists.sourceforge.net List-Id: linux-ext4.vger.kernel.org While getting re-aquainted with perf, and after upgrading to the current version, I see that do_page_fault, unmap_vmas, get_page_from_freelist, handle_mm_fault, __do_fault and T.1339 tend to get the most time when the kernel is spinning. T.1339 is in this part of kallsyms: ,----< grep -E -C9 ^c1027750 /proc/kallsyms > | c10266a0 T sched_setscheduler_nocheck | c10266c0 T sched_setscheduler | c10266e0 t do_sched_setscheduler | c1026770 T sys_sched_setparam | c1026790 T sys_sched_setscheduler | c10267c0 T sched_fork | c1026900 T task_oncpu_function_call | c1026960 T print_cfs_rq | c1027640 T scheduler_tick | c1027750 t T.1339 | c10277f0 T schedule_tail | c1027830 t ftrace_raw_output_sched_kthread_stop | c1027930 t ftrace_raw_output_sched_kthread_stop_ret | c1027a30 t ftrace_raw_output_sched_wait_task | c1027b40 t ftrace_raw_output_sched_switch | c1027c90 t ftrace_raw_output_sched_migrate_task | c1027da0 t ftrace_raw_output_sched_process_wait | c1027eb0 t ftrace_raw_output_sched_process_fork | c1027fc0 t ftrace_raw_output_sched_stat_runtime `---- suggesting that T.1339 is part of sched. This leaves the impression that the issue is related to either scheduling or paging. I don't see any commits in the rc6..rc7 timeframe which stand out as likely suspects. -JimC -- James Cloos OpenPGP: 1024D/ED7DAEA6 ------------------------------------------------------------------------------ SOLARIS 10 is the OS for Data Centers - provides features such as DTrace, Predictive Self Healing and Award Winning ZFS. Get Solaris 10 NOW http://p.sf.net/sfu/solaris-dev2dev