Date: Tue, 22 Apr 2008 22:34:35 +0200 From: Jeremie Le Hen <jeremie@le-hen.org> To: freebsd-current@FreeBSD.org Cc: Daichi GOTO <daichi@freebsd.org>, Masanori OZAWA <ozawa@ongs.co.jp> Subject: unionfs makes -CURRENT very sluggish Message-ID: <20080422203435.GA92168@obiwan.tataz.chchile.org>
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Hi,
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.
Best regards,
--
Jeremie Le Hen
< jeremie at le-hen dot org >< ttz at chchile dot org >
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