Messages in this thread | | | Date | Wed, 6 Jan 2010 13:04:00 -0600 | From | Clark Williams <> | Subject | [RFC] [rt-tests] change to cyclictest behavior |
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RT-ers,
I have a problem with the way cyclictest sets up measurement threads, but before I went and changed things I thought I would ask if people cherished this particular behavior.
Currently, when cyclictest is run with multiple threads (i.e. -t option) it distributes both the sample interval and the realtime priority by adding the 'distance' parameter to the interval and decrementing the priority by one. This means if you have a distance of 500us (default), a specified RT priority of 95 and start four threads, they will be started with the following parameters:
$ cyclictest -t4 -p95
Will give you:
thread priority sample interval 0 95 500 1 94 1000 2 93 1500 3 92 2000
What I'd like to do is modify this logic so that when '-a' (affinity) is specified, the priority and sample interval will not be altered. I don't think there's any point in distributing the priority's and sample intervals when the measurement threads are pinned to their own CPU.
So:
$ cyclictest -t4 -p95 -a
Would have each thread at SCHED_FIFO 95 and a sample interval of 500us.
Note that this behavior also occurs when the histogram (-h) option is specified).
Thoughts?
Clark [unhandled content-type:application/pgp-signature] | |