Performance Monitoring features for Cortex A8

Note: This was originally posted on 22nd January 2010 at http://forums.arm.com

Hi,

I am trying to use the performance counter feature in Cortex A8. I have downloaded the sample code given here : [url="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka4237.html"]http://infocenter.arm.com/help/index.jsp?t...aqs/ka4237.html[/url]

I am able to find the cycles taken via the cycle counter. But when I set an event to count, the counter always printing zero. The register contents when viewed in RV Debugger shows the contents to be untouched(all excalamation marks!!)..even the cycle counter is not showing its contents.

It would be of great help if you could give some pointers regarding what to check for/what I might be missing out?

Thanks,
Smitha Joseph
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  • Note: This was originally posted on 19th September 2011 at http://forums.arm.com

    Hi Smitha,


    I am experiencing the same problems as you - the cycle counter works, but not the performance counters (always 0). I have tested this by running the necessary code in the kernel, i.e., in privileged mode, as a kernel module.

    What I have found is that the DBGEN signal needs to be raised for the counters to work as well as the cycle counter, but I do not know how to raise this line from software. Do you think this could be the problem? Have you found out what was your problem?

    Any solutions you may have found to this problem would be greatly appreciated!


    Stein
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  • Note: This was originally posted on 19th September 2011 at http://forums.arm.com

    Hi Smitha,


    I am experiencing the same problems as you - the cycle counter works, but not the performance counters (always 0). I have tested this by running the necessary code in the kernel, i.e., in privileged mode, as a kernel module.

    What I have found is that the DBGEN signal needs to be raised for the counters to work as well as the cycle counter, but I do not know how to raise this line from software. Do you think this could be the problem? Have you found out what was your problem?

    Any solutions you may have found to this problem would be greatly appreciated!


    Stein
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