Re: getting processor numbers

Eric Dumazet
2007-04-04T05:46:58Z

H. Peter Anvin a écrit :
> Jeremy Fitzhardinge wrote:
>> H. Peter Anvin wrote:
>>> 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.
>> P4 manual says that if one processor modifies data within 2k of another
>> processor executing code, it will trash the entire trace cache.
>
> Yuck. Didn't realize the P4 was that sensitive. OK, so at the least we
> need a half-page of separation.

Yes but vsyscall API currently defines 4 entry points :

vsyscall0 (vgettimeofday) = ADDR
vsyscall1 (vtime) = ADDR+1024
vsyscall2 (vgetcpu) = ADDR+2048
vsyscall3 (vxxxxx) = ADDR+3072