From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josef Bacik Subject: Re: Boot speed/mount time regression with 3.4.0-rc2 Date: Thu, 12 Apr 2012 09:37:48 -0400 Message-ID: <20120412133747.GE1924@localhost.localdomain> References: <1333986823.2928.6.camel@ayu> <1333991404.2817.6.camel@ayu> <20120409205429.GB6958@localhost.localdomain> <1334006446.2678.0.camel@ayu> <20120410151645.GC2296@localhost.localdomain> <20120411170422.GA2506@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Cc: Josef Bacik , Calvin Walton , linux-btrfs@vger.kernel.org, Chris Mason To: Ahmet Inan Return-path: In-Reply-To: List-ID: On Thu, Apr 12, 2012 at 11:22:51AM +0200, Ahmet Inan wrote: > On Wed, Apr 11, 2012 at 7:04 PM, Josef Bacik wrote= : > > On Wed, Apr 11, 2012 at 05:26:29PM +0200, Ahmet Inan wrote: > >> On Tue, Apr 10, 2012 at 5:16 PM, Josef Bacik wr= ote: > >> > On Mon, Apr 09, 2012 at 05:20:46PM -0400, Calvin Walton wrote: > >> >> On Mon, 2012-04-09 at 16:54 -0400, Josef Bacik wrote: > >> >> > On Mon, Apr 09, 2012 at 01:10:04PM -0400, Calvin Walton wrote= : > >> >> > > On Mon, 2012-04-09 at 11:53 -0400, Calvin Walton wrote: > >> >> > > > Hi, > >> >> > > > > >> >> > > > I have a system that's using a dracut-generated initramfs= to mount a > >> >> > > > btrfs root. After upgrading to kernel 3.4.0-rc2 to test i= t out, I've > >> >> > > > noticed that the process of mounting the root filesystem = takes much > >> >> > > > longer with 3.4.0-rc2 than it did with 3.3.1 - nearly 30 = seconds slower! > >> >> > >> >> > > And the bisect results are in: > >> >> > > 285ff5af6ce358e73f53b55c9efadd4335f4c2ff is the first bad c= ommit > >> >> > > commit 285ff5af6ce358e73f53b55c9efadd4335f4c2ff > >> >> > > Author: Josef Bacik > >> >> > > Date: =A0 Fri Jan 13 15:27:45 2012 -0500 > >> >> > > > >> >> > > =A0 =A0 Btrfs: remove the ideal caching code> > >> >> > > >> >> > Ok can you give this a whirl? =A0You are going to have to boo= t/reboot a few times > >> >> > to let the cache get re-generated again to make sure it's tak= en effect, but > >> >> > hopefully this will help out. =A0Thanks, > >> >> > >> >> Unfortunately, it doesn't seem to help. Even after 3 or 4 reboo= ts with > >> >> this patch applied I'm still seeing the same delay. > >> >> > >> > > >> > Ok drop that previous patch and give this one a whirl, it helped= on my laptop. > >> > This is only =A0half of the problem AFAICS, but it's the easier = half to fix, in > >> > the meantime I need to lock down why we're not writing out cache= for a bunch of > >> > block groups, but thats trickier since the messages I need are s= pit out while > >> > I'm shutting down, so I need to get creative. =A0Let me know if/= how much this > >> > helps. =A0Thanks, > >> > >> i have tried your patch and my system still needs several minutes = to boot > >> until it can be used. > >> Also tried to reboot several times - it doesn't look like its gett= ing better. > >> The last thing the system does when its shutting down is a read-on= ly > >> remount of "/" so no umount. > >> Booting was much faster before i pulled for-linus a few weeks ago = but > >> i couldn't find the time to bisect it yet .. > >> > >> please also look at the attached dmesg.txt. > >> this is an core i3 system with 2x2TB BTRFS RAID1 and lots of > >> home directories and snapshots. > >> > >> I'm going to test this patch on twenty more computers but with > >> smaller HDDs and less files and see if it helps to speed up their > >> boot times. > >> > > > > Ok looks like you are running into a different problem. =A0Could yo= u maybe run > > bootchart and upload the resulting png somewhere so I can look and = see what all > > is running while you boot? =A0Thanks, >=20 > http://aam.mathematik.uni-freiburg.de/IAM/homepages/ainan/bootchart.p= ng >=20 > i have tried your patch now on the twenty more computers i mentioned = and > still it takes a minute to remount rw "/" on those, even after severa= l reboots. >=20 Oops responding to the whole list this time.. Um ouch your system appears to not be doing anything for like 300 secon= ds but sitting there. Can you hook up a console and capture sysrq+w while tha= ts going on? Also you are mounting with -o space_cache right? Can I see your d= mesg to make sure it's doing what it's supposed to? Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html