Messages in this thread | ![/](/images/icornerl.gif) | | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] optimize ia32 memmove | Date | 30 Dec 2003 12:17:59 -0800 |
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Followup to: <3FF15DAB.8080203@colorfullife.com> By author: Manfred Spraul <manfred@colorfullife.com> In newsgroup: linux.dev.kernel > > AMD recommends to perform bulk copies backwards: That defeats the hw > prefecher, and results in even better access patterns. Doesn't matter in > this case, memmove is never used for bulk copies. >
That's also a microoptimization for one particular microarchitecture *bug*. Hardware prefetchers are going omnidirectional going forward. Additionally, nearly all bulk copies are performed forward (DF=0) in existing codebases.
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