Re: [PATCH] Add support for Xtensa architecture

On 05/13/2015 08:24 AM, Max Filippov wrote:
> William,
> 
> On Wed, May 13, 2015 at 3:08 PM, William Cohen <[email protected]> wrote:
>> You can take a look at what was done for the aarch64 cortex a53
>> and cortex a57 to get an idea of other changes required to support the processor.
>>
>> https://sourceforge.net/p/oprofile/oprofile/ci/34d0065a1a790fc2be05a5ef1d8b0bbf28b814fe/
> 
> Thanks for the pointer.
> 
>> However, the kernel perf support is needed to provide events for the processor for oprofile to work.
>> Does the xtensa architecture provide some basic counter events such as cycle and instruction count?
> 
> Yes, it usually does have cycle counter and it may have other
> configurable performance counters.
> 

Hi Max,

It would be best to get the kernel's perf support develop and make sure that kernel perf tool work on xtensa, then develop the patches for oprofile. The manual does in the URL below mentions a ICOUNT and CCOUNT registers, but I don't know if that can be used (or if it is already used in the kernel):

http://ip.cadence.com/uploads/pdf/xtensalx_overview_handbook.pdf
http://0x04.net/~mwk/doc/xtensa.pdf

I am looking forward to OProfile supporting another architecture. 

-Will

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