On Wed, Jan 6, 2010 at 8:04 PM, Clark Williams <williams@xxxxxxxxxx> wrote: > 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? > Seems reasonable to me. Maybe it would also be nice to have a flag to get the old behaviour back even with -a? John -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
