Messages in this thread | | | Subject | Re: gcc inlining heuristics was Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning | From | David Woodhouse <> | Date | Wed, 21 Jan 2009 06:49:00 +1100 |
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On Tue, 2009-01-20 at 13:38 +0100, Ingo Molnar wrote: > > * Nick Piggin <npiggin@suse.de> wrote: > > > > > it seems like a nice opt-in thing that can be used where the aliases > > > > are verified and the code is particularly performance critical... > > > > > > Yes. I think we could use it in the kernel, although I'm not sure how > > > many cases we would ever find where we really care. > > > > Yeah, we don't tend to do a lot of intensive data processing, so it is > > normally the cache misses that hurt most as you noted earlier. > > > > Some places it might be appropriate, though. It might be nice if it can > > bring code size down too... > > I checked, its size effects were miniscule [0.17%] on the x86 defconfig > kernel and it seems to be a clear loss in total cost as there would be an > ongoing maintenance cost
They were talking about 'restrict', not strict-aliasing. Where it can be used, it's going to give you optimisations that strict-aliasing can't.
-- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation
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