Re: Intel P6 vs P7 system call performance

H. Peter Anvin
2002-12-18T05:31:27Z

Jeremy Fitzhardinge wrote:
> On Tue, 2002-12-17 at 09:55, Linus Torvalds wrote:
>
>>Uli, how about I just add one ne warchitecture-specific ELF AT flag, which
>>is the "base of sysinfo page". Right now that page is all zeroes except
>>for the system call trampoline at the beginning, but we might want to add
>>other system information to the page in the future (it is readable, after
>>all).
>
>
> The P4 optimisation guide promises horrible things if you write within
> 2k of a cached instruction from another CPU (it dumps the whole trace
> cache, it seems), so you'd need to be careful about mixing mutable data
> and the syscall code in that page.
>
> Immutable data should be fine.
>

Yes, you really want to use a second page.

-hpa