unionfs makes -CURRENT very sluggish
Daichi GOTO
daichi at freebsd.org
Wed Apr 23 05:14:15 UTC 2008
Jeremie Le Hen wrote:
> Hi,
>
> On Tue, Apr 22, 2008 at 10:34:35PM +0200, Jeremie Le Hen wrote:
>> I tried to compile lib/ncurses through unionfs. It is utterly slow, no
>> matter I mount with noatime or not.
>>
>> Relevant mounts:
>> % /usr/src on /space/chroot/usr/src (nullfs, local, read-only)
>> % <above>:/space/chroot/usr/src.union on /space/chroot/usr/src (unionfs, local)
>>
>> % root:~# chroot /space/chroot
>> % root:/# cd /usr/src/
>> % root:/# make buildenv
>> % # cd lib/ncurses
>> % # time make
>>
>> Compile time without noatime:
>> 5089.47 real 1670.72 user 3364.89 sys
>>
>> Compile time with noatime:
>> 5083.22 real 1664.10 user 3369.22 sys
>>
>> Now if I remove the unionfs mount and just use nullfs:
>> 255.47 real 150.51 user 83.82 sys
>>
>>
>> As you can see, most of the time is spent in kernel. I'm recompiling my
>> kernel with hwpmc right now in order to profile it. Any other debug
>> hint would be welcome.
>>
>> FWIW, "while sleep 1 ; do date ; done" runs jerkily when unionfs is run:
>> Tue Apr 22 21:20:06 CEST 2008
>> Tue Apr 22 21:20:13 CEST 2008
>> Tue Apr 22 21:20:17 CEST 2008
>> Tue Apr 22 21:20:22 CEST 2008
>> Tue Apr 22 21:20:29 CEST 2008
>>
>> Whereas it runs smoothly without unionfs.
>>
>> I'll give the result of hwpmc ASAP.
>
> I've upgraded to the latest -CURRENT and the problem went away. Sorry
> for the noise.
>
> Regards,
No problem :) Thanks for your report!
--
Daichi GOTO, http://people.freebsd.org/~daichi
More information about the freebsd-current
mailing list