On 2014/1/17 3:36, Will Deacon wrote: > On Thu, Jan 16, 2014 at 11:52:45AM +0000, Robert Richter wrote: >> (cc'ing Will) > > Thanks Robert, > >> The problem of too low sample periods could be solved on ARM by using >> perf's interrupt throttling, you might play around with: >> >> /proc/sys/kernel/perf_event_max_sample_rate:100000 >> >> I am not quite sure whether this works esp. for kernel counters and
Try to lower the value of perf_event_max_sample_rate, it works. Testing the following values: 100 500 1000 5000 10000 50000 for the last value, the command start to stall. Just a simple test. :) >> how userland can be notified about throttling. Throttling could be >> worth for operf too, not only for the oprofile kernel driver. >> >> From a quick look it seems there is also code in x86 that dynamically >> adjusts the rate which might be worth being implemented for ARM too. > > Are you referring to the perf_sample_event_took callback? If so, that > certainly looks worth persuing. I'll stick it on my list, thanks! > Thanks Will for doing this. Thanks Weng Meiling > Will > > . > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
