Re: [Xen-devel] Ping: [PATCH 0/4] HVM: produce better binary code

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 04.09.13 at 18:30, Tim Deegan <tim@xxxxxxx> wrote:
> I'm not certain, on a modern CPU, whether it's better to issue a series
> of PUSHes or a series of %rsp-relative MOVs and a SUB.

When I did the push/pop -> mov conversion for the non-HVM code
I did some measurements, with the result that the sequence of
moves was never slower but sometimes (usually on older CPUs)
faster. And the obvious benefit of moves is that interleaving them
with other code is less of a risk (in terms of breaking CPU-internal
bypasses/optimizations) than with pushes and pops.

Jan


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