From: Jiri Slaby <jslaby@suse.cz>
Subject: Re: Excessive stall times on ext4 in 3.9-rc2
Date: Sat, 06 Apr 2013 09:37:42 +0200
Message-ID: <515FD0C6.5050001@suse.cz>
References: <20130402142717.GH32241@suse.de> <20130402150651.GB31577@thunk.org> <20130402151436.GC31577@thunk.org> <20130403101925.GA7341@suse.de> <515F4DA3.2000000@suse.cz> <20130405231635.GA6521@thunk.org> <515FCEEC.9070504@suse.cz>
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To: Theodore Ts'o <tytso@mit.edu>, Mel Gorman <mgorman@suse.de>,
	linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>
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On 04/06/2013 09:29 AM, Jiri Slaby wrote:
> On 04/06/2013 01:16 AM, Theodore Ts'o wrote:
>> On Sat, Apr 06, 2013 at 12:18:11AM +0200, Jiri Slaby wrote:
>>> Ok, so now I'm runnning 3.9.0-rc5-next-20130404, it's not that bad, but
>>> it still sucks. Updating a kernel in a VM still results in "Your system
>>> is too SLOW to play this!" by mplayer and frame dropping.
>>
>> What was the first kernel where you didn't have the problem?  Were you
>> using the 3.8 kernel earlier, and did you see the interactivity
>> problems there?
> 
> I'm not sure, as I am using -next like for ever. But sure, there was a
> kernel which didn't ahve this problem.
> 
>> What else was running in on your desktop at the same time?
> 
> Nothing, just VM (kernel update from console) and mplayer2 on the host.
> This is more-or-less reproducible with these two.

Ok,
  dd if=/dev/zero of=xxx
is enough instead of "kernel update".

Writeback mount doesn't help.

>> How was
>> the file system mounted,
> 
> Both are actually a single device /dev/sda5:
> /dev/sda5 on /win type ext4 (rw,noatime,data=ordered)
> 
> Should I try writeback?
> 
>> and can you send me the output of dumpe2fs -h
>> /dev/XXX?
> 
> dumpe2fs 1.42.7 (21-Jan-2013)
> Filesystem volume name:   <none>
> Last mounted on:          /win
> Filesystem UUID:          cd4bf4d2-bc32-4777-a437-ee24c4ee5f1b
> Filesystem magic number:  0xEF53
> Filesystem revision #:    1 (dynamic)
> Filesystem features:      has_journal ext_attr resize_inode dir_index
> filetype needs_recovery extent flex_bg sparse_super large_file huge_file
> uninit_bg dir_nlink extra_isize
> Filesystem flags:         signed_directory_hash
> Default mount options:    user_xattr acl
> Filesystem state:         clean
> Errors behavior:          Continue
> Filesystem OS type:       Linux
> Inode count:              30507008
> Block count:              122012416
> Reserved block count:     0
> Free blocks:              72021328
> Free inodes:              30474619
> First block:              0
> Block size:               4096
> Fragment size:            4096
> Reserved GDT blocks:      994
> Blocks per group:         32768
> Fragments per group:      32768
> Inodes per group:         8192
> Inode blocks per group:   512
> RAID stride:              32747
> Flex block group size:    16
> Filesystem created:       Fri Sep  7 20:44:21 2012
> Last mount time:          Thu Apr  4 12:22:01 2013
> Last write time:          Thu Apr  4 12:22:01 2013
> Mount count:              256
> Maximum mount count:      -1
> Last checked:             Sat Sep  8 21:13:28 2012
> Check interval:           0 (<none>)
> Lifetime writes:          1011 GB
> Reserved blocks uid:      0 (user root)
> Reserved blocks gid:      0 (group root)
> First inode:              11
> Inode size:               256
> Required extra isize:     28
> Desired extra isize:      28
> Journal inode:            8
> Default directory hash:   half_md4
> Directory Hash Seed:      b6ad3f8b-72ce-49d6-92cb-abccd7dbe98e
> Journal backup:           inode blocks
> Journal features:         journal_incompat_revoke
> Journal size:             128M
> Journal length:           32768
> Journal sequence:         0x00054dc7
> Journal start:            8193
> 
>> Oh, and what options were you using to when you kicked off
>> the VM?
> 
> qemu-kvm -k en-us -smp 2 -m 1200 -soundhw hda -usb -usbdevice tablet
> -net user -net nic,model=e1000 -serial pty -balloon virtio -hda x.img
> 
>> The other thing that would be useful was to enable the jbd2_run_stats
>> tracepoint and to send the output of the trace log when you notice the
>> interactivity problems.
> 
> Ok, I will try.
> 
> thanks,
> 


-- 
js
suse labs