Date: Fri, 25 Sep 2009 15:21:56 -0400 From: Nathaniel W Filardo <nwf@cs.jhu.edu> To: freebsd-fs@freebsd.org Subject: Re: kern/139039: [zfs] zpool scrub makes system unbearably slow Message-ID: <20090925192156.GF22220@gradx.cs.jhu.edu> In-Reply-To: <200909251828.n8PISu6Z031842@freefall.freebsd.org>
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--c+qGut8k13HZAIeS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Sep 25, 2009 at 06:28:56PM +0000, pjd@freebsd.org wrote: > Synopsis: [zfs] zpool scrub makes system unbearably slow >=20 > State-Changed-From-To: open->feedback > State-Changed-By: pjd > State-Changed-When: ptk 25 wrz 2009 18:27:48 UTC > State-Changed-Why:=20 > Could you tell which threads are consuming most CPU time? > Pasting first few lines from 'top -SH' should be enough. >=20 >=20 > Responsible-Changed-From-To: freebsd-fs->pjd > Responsible-Changed-By: pjd > Responsible-Changed-When: ptk 25 wrz 2009 18:27:48 UTC > Responsible-Changed-Why:=20 > I'll take this one. >=20 > http://www.freebsd.org/cgi/query-pr.cgi?pr=3D139039 Thanks for looking at this. The system here is trying to build OpenLDAP in a jail, but that isn't frequently in the top. Typical output is... hydra# top -jSHP 267 processes: 15 running, 236 sleeping, 16 waiting CPU 0: 0.3% user, 0.0% nice, 97.4% system, 2.3% interrupt, 0.0% idle CPU 1: 10.7% user, 0.0% nice, 44.4% system, 1.8% interrupt, 43.0% idle Mem: 147M Active, 242M Inact, 926M Wired, 4008K Cache, 213M Buf, 672M Free Swap: 4096M Total, 4096M Free PID JID USERNAME PRI NICE SIZE RES STATE C TIME WCPU COMMAND 11 0 root 171 ki31 0K 64K RUN 1 376:41 57.18% {idle: cp= u1} 0 0 root -16 0 0K 3520K CPU0 0 6:04 13.96% {spa_zio_= 7} 0 0 root -16 0 0K 3520K - 0 5:58 13.33% {spa_zio_= 0} 0 0 root -16 0 0K 3520K - 0 5:58 13.13% {spa_zio_= 3} 0 0 root -16 0 0K 3520K - 0 6:01 13.09% {spa_zio_= 5} 0 0 root -16 0 0K 3520K RUN 0 6:01 13.04% {spa_zio_= 2} 0 0 root -16 0 0K 3520K RUN 0 6:00 13.04% {spa_zio_= 6} 0 0 root -16 0 0K 3520K - 0 5:59 12.65% {spa_zio_= 1} 0 0 root -16 0 0K 3520K - 1 6:00 12.11% {spa_zio_= 4} 42 0 root -8 - 0K 480K spa->s 0 4:50 8.54% {txg_thre= ad_enter} 4 0 root -8 - 0K 32K - 0 2:13 1.95% g_down 12 0 root -40 - 0K 544K WAIT 0 1:25 0.98% {swi2: ca= mbio} 0 0 root -16 0 0K 3520K - 0 0:24 0.20% {spa_zio_= 7} 0 0 root -16 0 0K 3520K - 1 0:23 0.20% {spa_zio_= 3} 12 0 root -64 - 0K 544K RUN 0 0:45 0.15% {vec1860:= mpt0} 0 0 root -16 0 0K 3520K - 1 0:58 0.10% {spa_zio} 12 0 root -32 - 0K 544K WAIT 0 1:58 0.05% {swi4: cl= ock} 42 0 root -8 - 0K 480K tx->tx 1 0:31 0.05% {txg_thre= ad_enter} 11 0 root 171 ki31 0K 64K RUN 0 774:48 0.00% {idle: cp= u0} The only thing that seems odd to me is that CPU1 is sitting essientially id= le (I have never seen CPU0 be idle when the system is scrubbing). The spa_zio= _* threads do in fact run on CPU1, but seemingly rarely. --nwf; --c+qGut8k13HZAIeS Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkq9GFQACgkQTeQabvr9Tc/2eQCgiBjhY1ELCuRCm5dxGuuNVTHR 6r4AnirXBp0M0nGdAWynt76opn56eG60 =rjj6 -----END PGP SIGNATURE----- --c+qGut8k13HZAIeS--
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