llvm dev - Jun 2014 - [LLVMdev] RDPMC inst use in llvm

I want to measure the performance of a JITed code snippet on MCJIT.
so I was planning to inject the RDPMC inst for the code generated through a
llvm IR builder.

Is there a patch available ? If there's a better way to do it please chime
in.

Thanks
sathvik
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On 6/19/14, 7:12 PM, sathvik wrote:
> I want to measure the performance of a JITed code snippet on MCJIT.
> so I was planning to inject the RDPMC inst for the code generated 
> through a llvm IR builder.
I assume the easier way to do this is to add an inline assembly call 
that uses the RDPMC instruction.  I don't think there's an LLVM IR 
intrinsic function that does it.

Regards,

John Criswell
>
> Is there a patch available ? If there's a better way to do it please 
> chime in.
>
> Thanks
> sathvik
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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Hi John,

I don't think its possible to add/insert an inline assembly into the LLVM
IR unless the IR interface provides some kind of stream writer into which
inline instructions can be written into.

I was thinking having an LLVM intrinsic function could be a first step
towards introducing PMU tool support in LLVM with which you can generate
code with built-in instrumentation. What do you think ?

Sathvik






On Fri, Jun 20, 2014 at 8:21 AM, John Criswell <criswell at illinois.edu>
wrote:
>  On 6/19/14, 7:12 PM, sathvik wrote:
>
>  I want to measure the performance of a JITed code snippet on MCJIT.
>  so I was planning to inject the RDPMC inst for the code generated through
> a llvm IR builder.
>
>
> I assume the easier way to do this is to add an inline assembly call that
> uses the RDPMC instruction.  I don't think there's an LLVM IR
intrinsic
> function that does it.
>
> Regards,
>
> John Criswell
>
>
>  Is there a patch available ? If there's a better way to do it please
> chime in.
>
>  Thanks
> sathvik
>
>
> _______________________________________________
> LLVM Developers mailing listLLVMdev at cs.uiuc.edu        
http://llvm.cs.uiuc.eduhttp://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>
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