Re: [PATCH v5 06/12] MIPS: add support for hardware performance events (mipsxx)

[David Daney <david.s.daney@gmail.com>]

On 05/28/2010 08:10 PM, Deng-Cheng Zhu wrote:
> 2010/5/28 David Daney<david.s.daney@gmail.com>:
>    
>> General comments:
>>
>> Can you separate the code that reads and writes the performance counter
>> registers from the definitions of the various counters themselves?
>>      
> [DC]:
> 1) Do you mean to move M_PERFCTL_* stuff out into pmu.h (or mipsregs.h)?
> If yes, that's OK. Again (my reply for [1/12] mentions this for the 1st
> time): After making Oprofile use Perf-events as backend (patches 8~12 do
> this), register definitions and read/write functions will locate in pmu.h
> (or mipsregs.h) and perf_event_$cpu.c, respectively.
> 2) According to your reply to [7/12], do you mean the perf counter
> read/write functions (such as mipsxx_pmu_read_counter()) are generic
> support functions? No, they are specific for mipsxx CPUs.
>
>    


Basically what I had in mind is that for all MIPS CPUs that have this 
style of performance counters, the counters are all read in the same 
manner (by reading the c0_PerfCnt registers).  However each CPU type has 
its own set of events that can be counted.

So I was thinking to separate the common code that accesses the 
registers from the CPU specific code that deals with the specific names 
and properties of the various events.


David Daney