Re: Recent kernel "mount" slow

Linus Torvalds
2012-11-22T19:22:07Z

Doesn't sound like a fsdevel issue since it seems to be independent of
filesystems. More like some generic block layer thing. Adding Jens
(and quoting the whole thing)

Jens, any ideas? Most of your stuff came in after -rc2, which would
fit with the fact that most of the slowdown seems to be after -rc2
according to Jeff.

Jeff, more bisecting would be good, though.

Linus

On Thu, Nov 22, 2012 at 4:30 AM, Jeff Chua <jeff.chua.linux@gmail.com> wrote:
> On Wed, Nov 21, 2012 at 11:46 PM, Jeff Chua <jeff.chua.linux@gmail.com> wrote:
>> On Wed, Nov 21, 2012 at 2:09 AM, Jan Kara <jack@suse.cz> wrote:
>>> I haven't heard about such problem so far. What filesystem are you using?
>>
>> I've tried ext2/ext3/ext4/reiserfs/btrfs ... all seems to be slower
>> than before. Seems to be fs independent.
>>
>>> Can you quantify 'is slower'? Bisecting would be welcome of course.
>>
>> Haven't measure, but it seems to be 1 sec instead of .3 sec to mount.
>> I'll start bisecting:(
>> So, since I've 6 mounts on start up, now it takes 4 seconds longer to boot up.
>
> I started bisecting, and it seems to have multiple points of slowing
> down. The latest kernel is really slow mounting /dev/sda1 (fs
> independent) ... 0.529sec. Kernel 3.6.0 took 0.012sec, Kernel
> 3.7.0-rc2 took 0.168sec. Again, these are very early results. I'm
> verifying them again.
>
>
> Jeff