Re: [PATCH 0/4] RFC: jump label - (tracepoint optimizations)

From: Roland McGrath
Date: Thu Sep 03 2009 - 17:12:13 EST


> This looks really interesting and desired. Once GCC adds this (or an
> equivalent) feature, i'd love to have your optimization in the
> kernel.

We expect it will be in gcc 4.5 and backported to Fedora's 4.4 pretty soon.
But it's not finalized yet, so we are only doing proof-of-concept so far.

> Basically everything that is optional and touches some very hot
> codepath would be eligible - not just tracepoints.

Sure. Any place you have a load+conditional-jump where that is too costly,
we can make it a nop that costs a only cycle or so. We probably want to
think a little harder about the nicest macro setup we can do to make
employing this trivial in the source.


Thanks,
Roland
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/