From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleg Drokin Subject: Re: Horrible ftruncate performance Date: Thu, 10 Jul 2003 19:44:55 +0400 Message-ID: <20030710154455.GI825@namesys.com> References: <20030710100111.GA825@namesys.com> Mime-Version: 1.0 Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com Content-Disposition: inline In-Reply-To: List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Szakacsits Szabolcs Cc: reiserfs-list@namesys.com Hello! On Thu, Jul 10, 2003 at 04:01:13PM +0200, Szakacsits Szabolcs wrote: > > May be this is because when system time was very big, the difference > > looked like a noise? ;) > You can decide yourself, > PIII/666: 0.00s usr, 917.83s sys 923.72s real, 99% CPU > Xeon/1.7: 0.00s usr, 862.79s sys, 865.13s real, 99% CPU Well, there is some difference. May be it can be explained by different drives, different partitioning and stuff like that. > > > Yes, I have whatever the latest distros ship. Right now I could check out > > > only Red Hat 9 and SuSE 8.2, they both have 3.6.4. The latest reiserfsprogs > > > is 3.6.8. > > Actually 3.6.4 has support for blocksizes other than 4k, this is > > controlled by -b switch of mkreiserfs (run it without arguments and it > > will tell you) man page on mkreiserfs (in SuSE 8.2 at least) have it > > listed too. > Both SuSE 8.2 and Red Hat 9 mkreiserfs manual say: > -b | --block-size N > N is block size in bytes. 4096 only for now. Ah, the safety measure ;) > > The 4k blocksize is not FS limit, this is VFS limit related to the fact > > that buffer size cannot be bigger than PAGE_SIZE. > Yes but people aren't really interested in this. FreeBSD uses 8 kB for at > least about 6 years by default and NTFS max 64 kB for a decade (frequently > used in benchmarks and when high performance is needed and make sense). Sigh, so we are all doomed. > If today I take a stock kernel, which main Linux filesystems support bigger > than 4 kB block size? None. iso9660 fs have pretty big blocksize, I think. Too bad you can only read from it ;) Bye, Oleg