perfasm and the <kernel> region

[Chris Vest]

Hi,

I have a benchmark where perfasm reports that about 50% of the time is spent in the kernel. It’s an IO heavy benchmark, so it sounds reasonable. However, some locks are also being juggled, which may cause threads to be blocked.

I’m assuming the time spent in the system calls for the IO and the blocking/unblocking of threads are both included in the <kernel> region. Would it be possible to break them out? I tried strace’ing the benchmark, but the overhead of strace is so big that it changes the behavioural patterns of the code, ruining the measurement.

Cheers,
Chris