Messages in this thread | | | Date | Sat, 24 Jun 2006 13:10:00 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH] fcache: a remapping boot cache |
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On Sat, Jun 24 2006, James wrote: > Set this up on my laptop yesterday with some awesome results. I'm > using 2.6.17-ck1 which has v2.1. > > Heres some bootcharts, before, after, and a prime run. > > http://archlinux.org/~james/normal.png > http://archlinux.org/~james/fs-fcache.png > http://archlinux.org/~james/fs-fcache-prime.png > > Repeated boots show about the same 6 second improvement, 32 down to 26 > seconds. Looking at the slowdowns in the fs-fcache run, most are due > to cpu load, waiting on network or, modprobe, and not disk access. X > now starts nearly instantaneously. > > As an experiment, I primed my cache right through to logging into my > desktop environment. It was so effective, that now when I login, the > GNOME splash screen only flickers onto the screen briefly, and the > panels appear almost instantly. This is a big improvment over without > fcache, where you'd see each component of GNOME being loaded on the > splash screen, nautilus, metacity, and the panels would take quite a > bit of time to render and load all their applets. > > Impressive work, I hope to see it broadened to other filesystems, > improved and merged to vanilla soon because it has clear improvements.
Thanks for giving it a spin! I have plans to implement some improvements on monday that will speed it up even more, I hope I can talk you into retesting it then. Basically it make sure we always get full speed out of the drive by extending the 4kb reads with a sliding window cache. That will help both drive efficiency, and also speed up the cases where sub sequent boots differ just a little bit from the primed boot (often the case with parallel init scripts). It should win you a few seconds more in total, would be my guess.
I hope to be able to extend it to xfs and reiser in the very near future as well, should not be hard to do.
-- Jens Axboe
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