Hello, the disk performance of hdparm -tT /dev/sda is the same as using the dd tests. /dev/sda: Timing buffer-cache reads: 12352 MB in 2.00 seconds = 6183.12 MB/sec Timing buffered disk reads: 152 MB in 3.04 seconds = 50.04 MB/sec The 20% cpu usage in the idle Linux partition (without top running) is real, the IVM provides correct statistics for the VIOS 1.2, and AIX partitions, only Linux is using significant CPU if it is idle. uname -a: Linux linux 2.6.5-7.97-pseries64 #1 SMP Fri Jul 2 14:21:59 UTC 2004 ppc64 ppc64 ppc64 GNU/Linux Could it be that the kernel has some kind of idle polling? Can other users confirm this behavior? Helmut Joachim Plack wrote:
On Mon, Jan 16, 2006 at 10:58:12PM +0100, Helmut Tschemernjak wrote:
Hello,
I am using an p520 with Virtual IO Server 1.2, testing Suse Server 9 within one partition. I just installed it, no services are being used, Linux top says it is 100% idle, but the IBM partition manger (IVM) says it is about 10-20% busy. If I use an idle AIX 5.3-03 within an partition, this uses just 0-1% CPU.
No idea so far, I´d have to ask IBM about there software. May be just a reporting problem.
Another problem I found is disk performance, I use dd from the RAW device to /dev/null with a 1024k blocksitz, with Linux gets about 50MB per second, using the same disk with an AIX partition this gives me about 85MB/sec.
Mmh. did you try different blocksizes, esp. 4k would be of interest? What does 'hdparm -tT' report on the raw device?
Bye, Jack.
-- Joachim Plack, tel suse@461, mail jplack@suse.de SLES on POWER = SATISFACTION GUARANTEED We'll send you another copy if it fails.