In most of your results, your CPU usage is very high. Once you get to about 90% usage, you really can't do much else, unless you can improve the CPU usage. Guy > -----Original Message----- > From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid- > owner@xxxxxxxxxxxxxxx] On Behalf Of Holger Kiehl > Sent: Tuesday, August 30, 2005 3:09 PM > To: Mark Hahn > Cc: linux-raid; linux-kernel > Subject: Re: Where is the performance bottleneck? > > On Mon, 29 Aug 2005, Mark Hahn wrote: > > >> The U320 SCSI controller has a 64 bit PCI-X bus for itself, there is no > other > >> device on that bus. Unfortunatly I was unable to determine at what > speed > >> it is running, here the output from lspci -vv: > > ... > >> Status: Bus=2 Dev=4 Func=0 64bit+ 133MHz+ SCD- USC-, > DC=simple, > > > > the "133MHz+" is a good sign. OTOH the latency (72) seems rather low - > my > > understanding is that that would noticably limit the size of burst > transfers. > > > I have tried with 128 and 144, but the transfer rate is only a little > bit higher barely measurable. Or what values should I try? > > > > >> Version 1.03 ------Sequential Output------ --Sequential Input- > --Random- > >> -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- > --Seeks-- > >> Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP > /sec %CP > >> Raid0 (8 disk)15744M 54406 96 247419 90 100752 25 60266 98 226651 29 > 830.2 1 > >> Raid0s(4 disk)15744M 54915 97 253642 89 73976 18 59445 97 198372 24 > 659.8 1 > >> Raid0s(4 disk)15744M 54866 97 268361 95 72852 17 59165 97 187183 22 > 666.3 1 > > > > you're obviously saturating something already with 2 disks. did you > play > > with "blockdev --setra" setings? > > > Yes, I did play a little bit with it but this only changed read > performance, > it made no measurable difference when writting. > > Thanks, > Holger > > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
