Re: getting processor numbers

[Eric Dumazet]

H. Peter Anvin a Ãcrit :
> Eric Dumazet wrote:
> > There is one thing that always worried me.
> >
> > Intel & AMD manuals make clear that mixing data and program in the 
> > same page is bad for performance.
> >
> > In particular, x86_64 vsyscall put jiffies and other 
> > vsyscall_gtod_data_t right in the midle of code. That is certainly not 
> > wise.
> >
> > A probably sane implementation should use two pages, one for code, one 
> > for data.
>
> Mutable data should be separated from code.  I think any current CPU 
> will do fine as long as they are in separate 128-byte chunks, but they 
> need at least that much separation.
>
> Readonly data does not need to be separated from code.

Yes... jiffies & vsyscall_gtod_data_t is writen HZ times per second.

Not really readonly I'm afraid.


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