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Re: About adding OMPT into GNU's libgomp

On Mon, Apr 13, 2015 at 11:14:56AM +0200, Harald Servat wrote:
>   we're considering in adding OMPT [1] into the GNU OpenMP runtime. In
> brief, OMPT is a specification of an API for performance analysis
> tools such as TAU, Extrae and HPCToolkit. It mainly consists of calls
> that allow querying the state of the threads and callbacks to notify a
> tool of various OpenMP runtime events during an execution.
>   Before we start, we'd like to know if there is someone else working
> on this direction. And if so, could we cooperate?

Not to my knowledge.

The only thing I'd like to say is that it would be nice if the changes
didn't affect performance of non-analyzed/traced apps, so if changes to hot
code paths are needed, they should be done with care, guarded with
__builtin_expect and benchmarked that they don't slow normal OpenMP code
paths significantly.

>   If there's nobody working on that, how should we start? According to
> the GCC webpage, GCC 5 is open for regression and doc fixes only [2],
> so it could considered mature enough to be a starting point? Or should
> we start in GCC 4.9.x? That being said, I've seen that there's a copy
> of GCC in GitHub [3]; should we clone it, branch to GCC 5 (if that
> exists), and then work on a local branch until we can send you some
> patches? Or do you suggest a different work plan?

Please see what Jonathan wrote.  You really should start working on a branch
from the trunk, and work towards incorporating it into the trunk (stage1
of GCC 6, where the trunk is open for new features, closes usually in


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