Re: [patch] voluntary-preempt-2.6.8.1-P9

From: K.R. Foley
Date: Wed Aug 25 2004 - 11:02:19 EST


Lee Revell wrote:
On Tue, 2004-08-24 at 23:17, K.R. Foley wrote:

Ingo Molnar wrote:

http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8.1-P9



latency trace of ~148 usec in scsi_request? I don't know if this is real or not. Note the 79 usec here:

00000001 0.107ms (+0.079ms): sd_init_command (scsi_prep_fn)

Entire trace is here:

http://www.cybsft.com/testresults/2.6.8.1-P9/latency_trace7.txt


Is this possible? This is not the first time I have seen this. There is another one here:

http://www.cybsft.com/testresults/2.6.8.1-P9/latency_trace5.txt



This looks like a real latency. What is
/sys/block/sdX/queue/max_sectors_kb set to? Does lowering it help?

Lee


Well I had no sooner sent the last message and another one of these popped up. This one is 123 usec:

http://www.cybsft.com/testresults/2.6.8.1-P9/latency_trace12.txt

kr
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