Date: Wed, 22 Oct 2003 15:25:58 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: David Rhodus <drhodus@catpa.com> Cc: Dave Parker Smith <davep@vicor.com> Subject: Re: 4.8 ffs_dirpref problem Message-ID: <20031022145836.J21067@gamplex.bde.org> In-Reply-To: <E9300747-042B-11D8-8810-00039380DD2C@catpa.com> References: <E9300747-042B-11D8-8810-00039380DD2C@catpa.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, 21 Oct 2003, David Rhodus wrote: > I have one question, why do you have softupdates turned off ? > With softupdates it could be possible to get faster writes than using > an async mount. Soft updates have never been faster than async for me, and in recent simple tests (copying /usr/src) they have become significantly slower than even ordinary (non-soft-update, non-sync, non-async mounts): 2002/05/30 ---------- ffs-16384-2048-1: tarcp /e src: 278.82 real 0.76 user 14.99 sys ffs-16384-2048-as-1: tarcp /e src: 180.39 real 0.73 user 13.69 sys ffs-16384-2048-su-1: tarcp /e src: 181.98 real 0.69 user 13.81 sys 2003/09/23 ---------- ffs-16384-02048-1: tarcp /f src: 68.66 real 0.82 user 13.81 sys ffs-16384-02048-as-1: tarcp /f src: 41.09 real 0.83 user 11.25 sys ffs-16384-02048-su-1: tarcp /f src: 111.62 real 0.82 user 11.49 sys ffs-16384-02048-1 means ffs with a block size of 16384, a fragment size of 2048, soft updates and ffs^WUFS1, etc. (there was no ffs2 at the time of the old benchmark and the "-1" in it actually meant doreallocblks=1). The machine is Athlon 1600XP overclocked running -current at the time with only the following major changes: - main memory increased from 512MB to 1024MB. This increases the relevance of the test as a write benchmark by giving enough memory to keep the source of the copy cached. - target disk changed from an IBM-DTLA-307030 (30MB ATA) to an IC35L060AVVA07-0 (60MB ATA). The file system had size 13GB in both cases and was at a similar offset in the disks; this puts it closer to the outer tracks on the larger disk so accesses to it were faster (approx. 40MB/sec vs 29 MB/sec) Most of the real times were improved significantly by the hardware changes, but for some reason soft updates didn't benefit as much as the others. This behaviour is not dependent on the block/frag sizes or ffs1/2. Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20031022145836.J21067>