RE: oprofile support for PPC_E5500

-----Original Message-----
From: William Cohen [mailto:[email protected]] 
Sent: Thursday, July 07, 2016 10:33 AM
To: Beaman, Thomas; [email protected]
Subject: Re: oprofile support for PPC_E5500

On 07/06/2016 10:26 AM, Beaman, Thomas wrote:
> When I am running on my PPC E5500 system oprofile cannot detect the CPU
> 
>  
> 
> operf --version
> 
> Unable to obtain cpu_type
> 
>  
> 
> Looking at op_cpu_type.h I see entries for
> 
>  
> 
>                 CPU_PPC_E500MC, /**< e500mc */
> 
>                 CPU_PPC_E6500, /**< e6500 */
> 
>  
> 
> But no entry for the PPC E5500.  The E5500 is very similar to e500mc and the E6500.  Can support be added for this processor ?
> 
>  
> 
> Thanks,
> 
> Tom

Hi Tom,

It is not difficult to add support for additional processors to oprofile. The main question is does the kernel being used on the system support access to the PPC E5500 performance monitoring hardware.  OProfile now uses the linux perf infrastructure in the kernel.  If that is available on the machine the command "perf list" should list out the available events and include some that are hardware events.  For the older method that is no longer supported in the current version of oprofile the kernel provided a oprofile kernel module.  The kernel module provided information about what type of processor the machine was. 

To add support for a new process there will need to be some additions in oprofile libop files to identify the processor type.  descriptions of the events in events/ppc for the processor.  The events might be similar to other existing processors and you might be able to map the processor to an existing set of events, but there can be differences that require separate set of files describing the events.

-Will

>>>>>>>>>>>>>>>>>


Hi Will,

The kernel I have does support a current version of OProfile. I have OProfile 1.1.0 running on a 4.1 kernel on a different CPU (X86_64).  I have checked and perf does list the following hardware events for the ppc E5500 target. 

  branch-instructions OR branches                    [Hardware event]
  branch-misses                                      [Hardware event]
  cache-misses                                       [Hardware event]
  cpu-cycles OR cycles                               [Hardware event]
  instructions                                       [Hardware event]
  stalled-cycles-backend OR idle-cycles-backend      [Hardware event]
  stalled-cycles-frontend OR idle-cycles-frontend    [Hardware event]

Michael Petlan has also replied with a patch for the ppc-e5500 that I will try. Thanks for your quick reply,  let me know if there is any other info I can supply.

Tom



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