Re: [Xen-devel] [RFC PATCH] p2m-pt: avoid get the pte falgs repeatedly.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 17.11.16 at 09:24, <liang.z.li@xxxxxxxxx> wrote:
> There are a lot of code try to get the pte flags repeatedly, why
> not save the result and reuse it in the following code? It can help
> to save some CPU cycles and make the code cleaner, no?
> 
> I am not sure if this is the right direction, just change one place.

Did you compare generated code with and without this change? A
compiler doing well optimization wise may produce better code in at
least some of the cases: The calculation involved in lNe_get_flags()
may be possible to completely elide, and hence your patch may
increase register pressure / stack consumption due to the new
variable. But of course a benefit of the change is better overall
readability ...

In any event you'd need to address various style issues before
such a patch could be accepted.

Jan


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