Cavium mips64 perf counters

Cavium mips64 perf counters

[Giant Sand Fan's]

Hi,

I'm trying to calculate de CPU load by access the performance counters
in mips and I haved reading in the cp0 but my problem is that I cannot
find documentation about the real meaning of these counters :

1.-LOG_PERF_CNT_NISSUE : ¿means cycle with no issue?

2.-LOG_PERF_CNT_SISSUE : ¿means cycle with     issue?

3.-LOG_PERF_CNT_DISSUE: ¿means cycle with double issue?


so CPU load will be == 2*100/(1+2) , in the period of time.

any clue...



thanks

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Re: Cavium mips64 perf counters

[David Daney]

On 04/26/2010 06:40 AM, Giant Sand Fan's wrote:
> Hi,
>
> I'm trying to calculate de CPU load by access the performance counters
> in mips and I haved reading in the cp0 but my problem is that I cannot
> find documentation about the real meaning of these counters :
>
> 1.-LOG_PERF_CNT_NISSUE : ¿means cycle with no issue?
>
> 2.-LOG_PERF_CNT_SISSUE : ¿means cycle with     issue?

Single issue.

>
> 3.-LOG_PERF_CNT_DISSUE: ¿means cycle with double issue?
>

That's right.  And PERF_CNT_CLK is the number of cycles.

David Daney

Re: Cavium mips64 perf counters

[Giant Sand Fan's]

0h, thank you David.

So can I do something like :

A.-) %CPU == (LOG_PERF_CNT_SISSUE)+(LOG_PERF_CNT_DISSUE*2)*100/CVMX_LOG_PERF_CNT_CLK

or

B.-) %CPU == (CVMX_LOG_PERF_CNT_ISSUE*100)/CVMX_LOG_PERF_CNT_CLK


I setup and read perf counters with :

mtc0 %0, $25, 0
dmfc0 %0, $25, 1

but I think that I can only read two counters so I can only use "B".

... or I'm totally wrong



2010/4/26 David Daney <ddaney@caviumnetworks.com>:
> On 04/26/2010 06:40 AM, Giant Sand Fan's wrote:
>>
>> Hi,
>>
>> I'm trying to calculate de CPU load by access the performance counters
>> in mips and I haved reading in the cp0 but my problem is that I cannot
>> find documentation about the real meaning of these counters :
>>
>> 1.-LOG_PERF_CNT_NISSUE : żmeans cycle with no issue?
>>
>> 2.-LOG_PERF_CNT_SISSUE : żmeans cycle with     issue?
>
> Single issue.
>
>>
>> 3.-LOG_PERF_CNT_DISSUE: żmeans cycle with double issue?
>>
>
> That's right.  And PERF_CNT_CLK is the number of cycles.
>
> David Daney
>



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