Re: [patch 9/9] Scheduler profiling - Use conditional calls

Andi Kleen
2007-05-31T22:33:34Z

> I see your point, but there is a level of control on the branch I would
> lack by doing so: the ability to put the call in either the if or else
> branch. It is an optimization on i386.

What does it optimize exactly?

> Also, I live in the expectation that, someday, the gcc guys will be nice
> enough to add some kind of support for a nop-based jump that would
> require code patching to put a jump instead. If it ever happens, my
> macro could evolve into this for newer compiler versions, which I could
> not do with the if() statement you are proposing.

If that ever happens we couldn't use it anyways because Linux still
has to support old compilers for a long time. And when those are dropped the
code could be updated.

-Andi