> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of Brian Candler > Sent: Friday, January 19, 2007 7:07 AM > To: Vijay Sankar > Cc: Marc Balmer; Claudio Jeker; misc@openbsd.org > Subject: Re: Performance Statistics: -current > > On Thu, Jan 18, 2007 at 12:03:05PM -0600, Vijay Sankar wrote: > > > if top shows ~20% system load, even when idle, try > disabling iic and ichiic > > > in UKC. sth we have to do here with an ASUS server. > > > > Thank you very much for your reply. > > > > I did not notice the system load to be very high (it was > 3.5% or so when > > building > > Are you sure you saw only 3.5% CPU utilisation while building > the OpenBSD > base system? That means the CPU was idle almost all of the time. > > If true, it means the system was spending most of its time waiting for > something else before it could continue - probably the disk. > > Try looking at the output of "iostat -w2" while building. > Particularly of > interest is the t/s (transfers per second) column. > > When compiling code, most transfers will be small. A single hard drive > spinning at 7200rpm is in theory capable of 240 transfers per second > (assuming each transaction requires the platter to rotate on > average by half > a turn),
That doesn't seem like correct analysis. > so values in the range 200-300 are to be expected. > I think you're a phenomenologist. Me too, though. I saw this store worker unloading a shopping cart starting with the boxes on top, so I'm pretty sure workers put lowest priority boxes on the bottom of the cart. > If you are seeing much less than this, then maybe your disk > subsystem has a > problem - a badly setup RAID? No DMA? A faulty drive which is > doing retries? > A bad IDE cable? (Check for warnings in /var/log/messages) > Make sure there's no dust on the motherboard. I usually scrape some of the dust crud off the leading edges of the fans, too. > > If it looks like disk I/O is slow, then using a disk > benchmark program might > help you more systematically investigate and tweak. For > example, you will > find bonnie and bonnie++ in packages. > > If you post the full output of "dmesg", "mount" and "df -k", plus a > description of your disk subsystem, people might have some > more suggestions. > I suggest you buy an AMD opteron. > HTH, > > Brian.
