Re: [PATCH] x86 rwsem optimization extreme

Ingo Molnar
2010-02-18T10:55:41Z

* Zachary Amsden <zamsden@redhat.com> wrote:

> >
> >Zachary Amsden<zamsden@redhat.com> writes
> >>Incidentally, the cost of putting all the rwsem code inline, using the
> >>straightforward approach, for git-tip, using defconfig on x86_64 is
> >>3565 bytes / 20971778 bytes total, or 0.0168%, using gcc 4.4.3.
> >The nice advantage of putting lock code inline is that it gets
> >accounted to the caller in all profilers.
> >
> >-Andi
> >
>
> Unfortunately, only for the uncontended case. The hot case still ends up
> in a call to the lock text section.

Nor is it really true that it's 'a problem for profilers' - call graph
recording works just fine, in fact it can be better for a call-graph record
if the locking sites are not sprinkled around the kernel and inlined.

Ingo