On Thu, 6 Sep 2018 at 04:02, Tomasz Nowicki tnowicki@caviumnetworks.com wrote:
Hi Mathieu,
I have been looking into kernel code looking for ETF/ETR sampling frequency. So far I have found two places where we dump buffer's content:
By "sampling frequency" I will deduce that you mean "copy the content of the sink buffer to the perf's ring buffer".
- when thread is schedule out
Correct.
- by adding '-F <HZ>' perf option, every time process gets tick but the
<HZ> value has no influence to dumping buffer frequency
I wasn't aware of that one but in my opinion not realistic for coresight as it would seriously impact system performance. What is needed is an interrupt when the trace buffer is full, something the components currently don't support.
Mathieu
Does it make sense to control sampling frequency in this case? If yes, then how can we do it? Thanks in advance for your feedback.
Tomasz