On Wed, Aug 6, 2014 at 3:43 PM, Oon-Ee Ng <ngoonee.talk@xxxxxxxxx> wrote: > On Wed, Aug 6, 2014 at 10:40 AM, Anatol Pomozov > <anatol.pomozov@xxxxxxxxx> wrote: >> 'perf' is a great and very powerful tool that allow to debug problems >> like this. Run '# perf top -g -p $PID' and it will show where the >> process spends *cpu cycles*. It should be enough to understand what >> kworker thread does. For all curious minds I highly recommend to read >> this tutorial https://perf.wiki.kernel.org/index.php/Tutorial > > Thanks, if my boy gets to sleep early tonight I'll do that. Having tried that out, I don't really understand the output. It seems the first column is CPU usage and the second is...? IO? Anyway these are the top 3 things in my output after a short amount of time. Other things which are low in CPU usage and high in the second column are find_next_zero_bit and _raw_spin_lock. Not sure what I should glean from this. + 17.74% 0.10% [kernel] [k] __filemap_fdatawrite_range + 15.04% 0.02% [kernel] [k] filemap_fdatawrite_range + 9.93% 9.93% [kernel] [k] find_next_bit
