Re: Puzzling performance issue?

Posted in 2003

Andy Kent — 1 Dec 2003 04:12:38 -0800 — source: Usenet: comp.databases.informix

> High values (i.e. over 256) give high CPU usage How so? Andy

↪ replying to Andy Kent

TBP — Mon, 01 Dec 2003 14:58:01 +0000 — source: Usenet: comp.databases.informix

Andy Kent wrote: >>High values (i.e. over 256) give high CPU usage > > > How so? > > Andy 'cos kaio (or the aio vp) will be hammered when jumping ahead 512k (or 1 Mb on a 4k system) at a time. Perhaps I should have phrased it "higher CPU usage" - everything is relative.

↪ replying to TBP

Andy Kent — 2 Dec 2003 01:07:26 -0800 — source: Usenet: comp.databases.informix

I don't see how kaio / aio will get hammered more overall by 1 x 1024kB read rather than, say, 8 x 128kB reads. Or is just that you notice it more because you're not waiting for the disks? Andy TBP <TheBigPotatoe@Nospam.Nothere.Co.Uk> wrote in message news:<bqfkv4$136g$1@sp15at20.hursley.ibm.com>... > Andy Kent wrote: > >>High values (i.e. over 256) give high CPU usage > > > > > > How so? > > > > Andy > > 'cos kaio (or the aio vp) will be hammered when jumping ahead 512k (or 1 > Mb on a 4k system) at a time. > > Perhaps I should have phrased it "higher CPU usage" - everything is > relative.