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

K.R. Foley
2004-08-25T16:00:53Z

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