From mboxrd@z Thu Jan 1 00:00:00 1970 From: joe.landman@gmail.com Subject: Re: very slow file deletion on an SSD Date: Sat, 26 May 2012 20:10:45 -0400 Message-ID: References: <4FBF60D1.80104@gmail.com> <20120526231838.GR25351@dastard> <4FC16683.9060800@gmail.com> <20120527000701.GS25351@dastard> Mime-Version: 1.0 (1.0) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120527000701.GS25351@dastard> Sender: linux-raid-owner@vger.kernel.org To: Dave Chinner Cc: "xfs@oss.sgi.com" , linux-raid List-Id: linux-raid.ids Ok. Will do in a few hours Sent from my iPad On May 26, 2012, at 8:07 PM, Dave Chinner wrote: > On Sat, May 26, 2012 at 07:25:55PM -0400, Joe Landman wrote: >> [root@siFlash test]# ls -alF | wc -l >> 59 >> [root@siFlash test]# /usr/bin/time rm -f * >> ^C0.00user 8.46system 0:09.55elapsed 88%CPU (0avgtext+0avgdata >> 2384maxresident)k >> 25352inputs+0outputs (0major+179minor)pagefaults 0swaps > > It's burning an awful lot of CPU time during this remove. > >> [root@siFlash test]# ls -alF | wc -l >> 48 > > So, 48 files were removed, it was basically CPU bound and one took > 2.6 seconds. > > So, how big are the files, and does the one that took 2.6s have tens > of thousands of extents ('xfs_bmap -vp *' will dump the extent maps > for all the files)? > > if not, can you use perf top to get an ida of the CPU usage profile > duing the rm by doing: > > # perf record rm -f * > ..... > > and capturing the profile via: > > # perf report > profile.txt > > And attaching te profile.txt file so we can see where all the CPU > time is being spent? You can find perf in your kernel source tree > under the tools subdir.... > > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com