[Pvfs2-developers] IB support question

[Rob Ross]

Either name would be fine; PINT_ is a little better I suppose.

Rob

Pete Wyckoff wrote:
> bradles at parl.clemson.edu wrote on Wed, 22 Feb 2006 10:10 -0500:
>>   It appears that compile errors I'm running into with PVFS2 and 
>> Silverstorm/Mellanox infiniband are definitions in the ib code that 
>> duplicate definitions in kernel headers.  Specifically:
>>
>> #define likely(x)       __builtin_expect(!!(x), 1)
>> #define unlikely(x)     __builtin_expect(!!(x), 0)
>>
>>   Do you think it may be appropriate to call these
>>
>> PVFS2_likely and PVFS2_unlikely to avoid name collisions with kernel 
>> #defines?  We could also test for their existince, though then we 
>> couldn't be certain what the macro did exactly.  Any strong opinions?
> 
> None of the IB code interacts with the kernel code, but I guess the
> Silverstorm userspace IB headers must either pull in kernel headers
> (blecch) or define likely() for their own purposes.
> 
> I agree renaming those functions in the pvfs2 IB code is the way to
> go.  Perhaps a naming guru could suggest if we should change them
> to
>     PVFS2_likely
>     PVFS2_unlikely
> as you suggest or would prefer
>     PINT_likely
>     PINT_unlikely
> or even something to keep it BMI-specific?
> 
> It's just an optimization to help the compiler with branch
> prediction.  I try only to use it for assert-like things where the
> likelihood of the outcome is really obvious.
> 
> 		-- Pete
> _______________________________________________
> Pvfs2-developers mailing list
> Pvfs2-developers at beowulf-underground.org
> http://www.beowulf-underground.org/mailman/listinfo/pvfs2-developers
>