Date: Thu, 21 Dec 2006 23:16:41 -0600 From: Eric Anderson <anderson@centtech.com> To: Mark Kirkwood <markir@paradise.net.nz> Cc: freebsd-performance@freebsd.org Subject: Re: Cached file read performance Message-ID: <458B6A39.5040902@centtech.com> In-Reply-To: <458B3651.8090601@paradise.net.nz> References: <458B3651.8090601@paradise.net.nz>
next in thread | previous in thread | raw e-mail | index | archive | help
On 12/21/06 19:35, Mark Kirkwood wrote: > I recently did some testing on the performance of cached reads using two > (almost identical) systems, one running FreeBSD 6.2PRE and the other > running Gentoo Linux - the latter acting as a control. I initially > started a thread of the same name on -stable, but it was suggested I > submit a mail here. > > My background for wanting to examine this is that I work with developing > database software (postgres internals related) and cached read > performance is pretty important - since we typically try hard to > encourage cached access whenever possible. > > Anyway on to the results: I used the attached program to read a cached > 781MB file sequentially and randomly with a specified block size (see > below). The conclusion I came to was that our (i.e FreeBSD) cached read > performance (particularly for smaller block sizes) could perhaps be > improved... now I'm happy to help in any way - the machine I've got > running STABLE can be upgraded to CURRENT in order to try out patches > (or in fact to see if CURRENT is faster at this already!)... > > Best wishes > > Mark > > > ----------------------results-etc--------------------------------- > Machines > ======== > > FreeBSD (6.2-PRERELEASE #7: Mon Nov 27 19:32:33 NZDT 2006): > - Supermicro P3TDER > - 2xSL5QL 1.26 GHz PIII > - 2xKingston PC133 RCC Registered 1GB DIMMS > - 3Ware 7506 4x Maxtor Plus 9 ATA-133 7200 80G > - Kernal GENERIC + SMP > - /etc/malloc.conf -> >aj > - ufs2 32k blocksize, 4K fragments > - RAID0 256K stripe using twe driver > > Gentoo (2.6.18-gentoo-r3 ): > - Supermicro P3TDER > - 2xSL5QL 1.26 GHz PIII > - 2xKingston PC133 RCC Registered 1GB DIMMS > - Promise TX4000 4x Maxtor plus 8 ATA-133 7200 40G > - default make CFLAGS (-O2 -march-i686) > - xfs stripe width 2 > - RAID0 256K stripe using md driver (software RAID) > > Given the tests were about cached I/O, the differences in RAID > controller and the disks themselves were seen as not significant (indeed > booting the FreeBSD box with the Gentoo livecd and running the tests > there confirmed this). [..snip of useful results..] Aren't you also slightly testing parts of the file system code? Why not (since it is only read-only you are interested in) use FreeBSD's xfs support (only in -CURRENT however) and run the tests also? I'm just curious if it would make any difference - I would bet not much of any though. Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology An undefined problem has an infinite number of solutions. ------------------------------------------------------------------------
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?458B6A39.5040902>