From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Trofimovich Subject: Re: Boot speed/mount time regression with 3.4.0-rc2 Date: Sun, 22 Apr 2012 10:59:19 +0300 Message-ID: <20120422105919.28b027a0@sf.home> References: <20120410151645.GC2296@localhost.localdomain> <20120411170422.GA2506@localhost.localdomain> <20120412133747.GE1924@localhost.localdomain> <20120412142349.GI1924@localhost.localdomain> <20120413134716.GB1923@localhost.localdomain> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/kJjDkKw.HdZ7_3hnIPH/3WF"; protocol="application/pgp-signature" Cc: Josef Bacik , cwillu , Calvin Walton , linux-btrfs@vger.kernel.org, Chris Mason To: Ahmet Inan Return-path: In-Reply-To: List-ID: --Sig_/kJjDkKw.HdZ7_3hnIPH/3WF Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Sat, 21 Apr 2012 22:54:41 +0200 Ahmet Inan wrote: > On Fri, Apr 13, 2012 at 3:47 PM, Josef Bacik wrote: > > On Fri, Apr 13, 2012 at 02:26:19PM +0200, Ahmet Inan wrote: > >> On Fri, Apr 13, 2012 at 1:22 PM, Ahmet Inan > >> wrote: > >> > On Fri, Apr 13, 2012 at 8:49 AM, cwillu wrote: > >> >>> dmesg and fstab attached as requested. > >> >> > >> >> Need dmesg after you've hit alt-sysrq-w a couple times during the s= low period. > >> > > >> > here. > >> > > >> > i guess i should also increase dmesg history size next time. > >> > other than the slow boot, everything seems normal after 10-20minutes. > >> > > >> > fyi: the space_cache option is not really helping with those > >> > twenty computers. the one thing i observed is, that sometimes > >> > they reboot fast and only to reboot slow again after that. > >> > >> sorry for spaming the list with my dmesg files, > >> please tell me, how i could do better. > >> > >> here a more complete dmesg. > > > > Hrm so you are getting blocked task warnings just trying to mount the > > filesystem, so either your disk is really really really slow or there's > > something bigger going on. =C2=A0Let me think about this some and I'll = get back to > > you. >=20 > Josef, i finally found out something: >=20 > btrfs in kernel =3D> fast boot > btrfs as module =3D> very slow boot >=20 > and here see the results: > http://aam.mathematik.uni-freiburg.de/IAM/homepages/ainan/bootchart_btrfs= _in_kernel.png >=20 > this is much, much better! >=20 > I dont understand why btrfs as a module performs that bad on rotating dis= k. > On SSD i had no issues and also i never used space_cache before. There is a suspiction that putting space_cache (or anything else) to fstab = for rootfs does not get applied due to a bug: http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg16039.html Do all of your affected computers run 3.4.0-rc kernels? --=20 Sergei --Sig_/kJjDkKw.HdZ7_3hnIPH/3WF Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (GNU/Linux) iEYEARECAAYFAk+Tul0ACgkQcaHudmEf86oUGACfXAnQ3dwky031SgeYaav+w7IO oEEAnjVZSJXoMbDQhn6kj0OPyGlsuGvO =KWID -----END PGP SIGNATURE----- --Sig_/kJjDkKw.HdZ7_3hnIPH/3WF--