Re: Updated dynamic tick patches

From: Srivatsa Vaddagiri
Date: Fri Sep 02 2005 - 12:35:40 EST


On Thu, Sep 01, 2005 at 04:07:22PM +0300, Tony Lindgren wrote:
> Srivatsa, could you try the dyntick-test.c on your system after booting
> to init=/bin/sh to make the system as idle as possible?

Tony,
I get this o/p when I run your test on my SMP system with
2.6.13-mm1 + Con's latest patches (including the most recent
lost tick calculation patch that I posted after that).

Testing sub-second select and usleep
Test: select 0ms time: 0.000012s latency: 0.000012s status: OK
Test: usleep 0ms time: 0.000013s latency: 0.000013s status: OK
Test: select 100ms time: 0.099386s latency: -0.000614s status: OK
Test: usleep 100ms time: 0.104019s latency: 0.004019s status: OK
Test: select 200ms time: 0.200013s latency: 0.000013s status: OK
Test: usleep 200ms time: 0.204016s latency: 0.004016s status: OK
Test: select 300ms time: 0.300043s latency: 0.000043s status: OK
Test: usleep 300ms time: 0.304056s latency: 0.004056s status: OK
Test: select 400ms time: 0.400010s latency: 0.000010s status: OK
Test: usleep 400ms time: 0.404098s latency: 0.004098s status: OK
Test: select 500ms time: 0.499992s latency: -0.000008s status: OK
Test: usleep 500ms time: 0.504000s latency: 0.004000s status: OK
Test: select 600ms time: 0.600050s latency: 0.000050s status: OK
Test: usleep 600ms time: 0.603959s latency: 0.003959s status: OK
Test: select 700ms time: 0.699969s latency: -0.000031s status: OK
Test: usleep 700ms time: 0.704037s latency: 0.004037s status: OK
Test: select 800ms time: 0.800026s latency: 0.000026s status: OK
Test: usleep 800ms time: 0.803978s latency: 0.003978s status: OK
Test: select 900ms time: 0.900046s latency: 0.000046s status: OK
Test: usleep 900ms time: 0.904003s latency: 0.004003s status: OK
Testing multi-second select and sleep
Test: select 0ms time: 0.000005s latency: 0.000005s status: OK
Test: sleep 0ms time: 0.000006s latency: 0.000006s status: OK
Test: select 1000ms time: 1.000062s latency: 0.000062s status: OK
Test: sleep 1000ms time: 1.004069s latency: 0.004069s status: OK
Test: select 2000ms time: 2.000727s latency: 0.000727s status: OK
Test: sleep 2000ms time: 2.004141s latency: 0.004141s status: OK
Test: select 3000ms time: 3.000127s latency: 0.000127s status: OK
Test: sleep 3000ms time: 3.004048s latency: 0.004048s status: OK
Test: select 4000ms time: 4.000032s latency: 0.000032s status: OK
Test: sleep 4000ms time: 4.004827s latency: 0.004827s status: OK
Test: select 5000ms time: 5.000118s latency: 0.000118s status: OK
Test: sleep 5000ms time: 5.004131s latency: 0.004131s status: OK
Test: select 6000ms time: 5.997241s latency: -0.002759s status: OK
Test: sleep 6000ms time: 6.008025s latency: 0.008025s status: OK
Test: select 7000ms time: 6.997195s latency: -0.002805s status: OK
Test: sleep 7000ms time: 7.004180s latency: 0.004180s status: OK
Test: select 8000ms time: 8.000512s latency: 0.000512s status: OK
Test: sleep 8000ms time: 8.008116s latency: 0.008116s status: OK
Test: select 9000ms time: 8.996997s latency: -0.003003s status: OK
Test: sleep 9000ms time: 9.004279s latency: 0.004279s status: OK


Don't see any ERROR status. The negative latencies doesn't seem to sound
good. Do you see them too? I ran your test on my RH9 based T30 and
find several negative latencies there too.



--


Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017
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