On 03.09.2015 14:52, Vince Weaver wrote
The kernel itself has trouble going to 100Hz without causing a lot of
overhead and at 1kHz the NMI overhead gets high enough that the kernel
throttles things down. I haven't investigated why that is, it might be a
problem with how my tool is coded. For now I just gave up and am making
masurements at 10Hz.
OK thanks for this information. I can probably now exclude the current
perf-interface of the kernel.
Maybe this is also interesting for you then:
In the meantime I got some information for the x86 architecture. There,
the performance counters can be read directly in userspace by the
interface over MSR's similar to readmsr/msrtool, where a reliable
interval of <10ms can be achieved. [1]
For ARM, there seems to exist some specialized driver "gator" which I
didn't take a closer look.
Anyhow, I am currently looking at a Power7 system, and don't know of any
other interfaces there than perf/oprofile. I will continue to try to
find some more information about that.
Best regards,
Dennis
[1] *F. Oboril*, J. Ewert, and M. B. Tahoori, "High-Resolution Online
Power Monitoring for Modern Microprocessors," in Proceedings of Design,
Automation & Test in Europe (*DATE*), 2015, France. Online available:
*http://cdnc.itec.kit.edu/downloads/Papers/Oboril15DATE.pdf
*
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