FYI: Just note that I say overhead, which I assume to be the time it
take to do someting like getpid(), write(-1,...), select(-1, ...) (etc
that is immediatlely returned with -EINVAL by the kernel).
Since the kernel do execute a quite afew instructions beside the
int/iret sysenter/sysexit, it's an assumption that the int 80 is the
culprit.
I would be nice if someone bothered to try this on an windoze box.
(Un)fortunatly I live in a windoze free environment. :-)
TJ
On Fri, 2002-12-13 at 16:58, Ville Herva wrote:
On Fri, Dec 13, 2002 at 10:21:11AM +0100, you [Terje Eggestad] wrote:
>
> Well, it does make sense if Intel optimized away rdtsc for more commonly
> used things, but even that don't seem to be the case. I'm measuring the
> overhead of doing a syscall on Linux (int 80) to be ~280 cycles on PIII,
> and Athlon, while it's 1600 cycles on P4.
Just out of interest, how much would sysenter (or syscall on amd) cost,
then? (Supposing it can be feasibly implemented.)
I think I heard WinXP (W2k too?) is using sysenter?
-- v --
v@iki.fi
-- _________________________________________________________________________Terje Eggestad mailto:terje.eggestad@scali.no Scali Scalable Linux Systems http://www.scali.com
Olaf Helsets Vei 6 tel: +47 22 62 89 61 (OFFICE) P.O.Box 150, Oppsal +47 975 31 574 (MOBILE) N-0619 Oslo fax: +47 22 62 89 51 NORWAY _________________________________________________________________________
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