On 19 December 2016 at 07:45, Yehuda Yitschak yehuday@marvell.com wrote:
Hi Mathieu
After some more debug I was able to resolve the trace issue I had on Linux-4.9-rc1
If you remember I only got trace for CPU2 out of 4 CPUs which was really strange
Turns out the issue comes from some quirk in our busses
Our internal fabric is not able to write 64bit data to registers, only to memory
So the address comparators in the ETM got corrupted values and there wasn’t any match on address for most CPUs.
For some cryptic reason only CPU2 got somewhat reasonable comparator value (still not the intended, but a working one) and so it could generate trace
Now I am able to generate proper trace consistently.
Very good.
I was wondering how can I add latency or timing information to the trace
I noticed the cs_etm event can accept an option of “cycacc” and “timestamp“
How can I view this information later ?
Should I use perf script –f ?
That information, when configured on the cmd line, will end up in the perf.data file. From there it will be decoded and rendered by the openCSD library.
Mike, can you comment on the format of the information that will be found in the packet? Perhaps you have an example somewhere of traces generated by the "cycacc" and "timestamp" option?
You will definitely need to create your own scripts as nothing we have done so far uses those configuration parameters.
Thanks, Mathieu
Thanks a lot
Yehuda Yitschak
Marvell Semiconductor Ltd.