Re: 2.6.17-ck1: fcache problem...

[Jens Axboe <axboe@suse.de>]

On Sun, Jun 25 2006, Paolo Ornati wrote:
> On Sun, 25 Jun 2006 12:28:39 +0200
> Jens Axboe <axboe@suse.de> wrote:
> 
> > > [   26.673525] fcache: found serial 33, expected 34.
> > > [   26.673529] fcache: reprime the cache!
> > > [   26.673535] ext3: failed to open fcache (err=-22)
> > 
> > Hmm, and you are sure that the fs is properly umounted on reboot? Or is
> > it just remounted ro? It looks like fcache_close_dev() isn't being
> > called, so the cache serial doesn't match what we expect from the fs,
> > hence fcache bails out since it could indicate that the fs has been
> > changed without fcache being attached.
> 
> Ahh... it is the root fs and it's just remounted read-only by the
> standard Gentoo scripts ;)
> 
> I don't think that unmounting it is trivial (you need to chroot to a
> virtual FS or something...). Does any distro do it?

ro should be enough, something odd must be going on. I'll add it to the
list of things to test tomorrow.

> > What kind of speedup did you see?
> 
> with cold caches...
> 
> NORMAL
> from Grub to KDM login		42"5	(~6" to reach init)
> KDE 3.5.3 startup		10"
> Firefox				7"
> 
> FCACHE
> from Grub to KDM login		31"4	(~6" to reach init)
> KDE 3.5.3 startup		4"
> Firefox				2"4

Very nice!

-- 
Jens Axboe