Lee Revell wrote:
>On Fri, 2006-06-23 at 09:44 +0930, Jonathan Woithe wrote:
>
>
>>Despite what the log says, this was running a 2.0 GHz "Dothan"
>>Centrino CPU. Kernel was 2.6.16-rt25, distro was Slackware 10.2. Both
>>the stress tester and the monitor were run with RT privilege access.
>>The firewire interface used has a TI OHCI chipset.
>>
>>I apologise that the run was particularly short and that therefore the
>>statistics aren't particularly good, but it does seem to confirm the
>>observations you made on your machine. The large latencies only occur
>>when the stress tester is running.
>>
>>
>
>What if you run the latency tester at RT priority 99? Testing at 80 is
>not particularly useful.
>
>
Why not?
If the 1394 test user thread has a lower priority, and the ohci1394 irq
priority is also lower, there is no reason for the latency tester to be
preempted by them.
>If anything else is running at 99, what happens if you lower those other
>processes to 98?
>
>
I'll have to recheck, but if I remember correcly I have done this
experiment. The only thing at 99 is the system timer. I tried giving it
a lower priority than the latency test thread, which didn't change anything.
Pieter
Received on Fri Jun 23 16:15:03 2006
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