Messages in this thread | | | Subject | Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL) | From | Arjan van de Ven <> | Date | Thu, 27 Apr 2006 08:50:40 +0200 |
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On Thu, 2006-04-27 at 09:28 +0300, Pekka J Enberg wrote: > On Thu, 27 Apr 2006, Nick Piggin wrote: > > Not to dispute your conclusions or method, but I think doing a > > defconfig or your personal config might be more representative > > of % size increase of text that will actually be executed. And > > that is the expensive type of text. > > True but I was under the impression that Arjan thought we'd get text > savings with GCC 4.1 by making kfree() inline.
not savings in text size, I'll settle for the same size. What we gain is less branches in the hotpath... eg a kfree that gets optimized now has one less branch. Note that the branch predictor isn't going to help you for these 100% cases, since the same branch "slot" is shared between all callers; with this inline the branch predictor at least gets to keep stats for each of the callers individually. That is where the gain is....
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