Re: [uml-devel] SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386)

Borislav Petkov
2011-08-23T21:11:08Z

On Tue, Aug 23, 2011 at 05:06:03PM -0400, H. Peter Anvin wrote:
> On 08/23/2011 01:56 PM, Borislav Petkov wrote:
> >
> > But no, I don't think the difference has disappeared - to the contrary,
> > AFAICT, the intention is for SYSCALL to be the fastest way to do
> > syscalls on x86 due to diminished number of segment checks etc. INT80
> > is legacy, slower, etc. I believe Andy measured a similar situation on
> > Sandy Bridge with SYSCALL having latencies in the tens of nsecs range
> > and INT80 being much slower. Ingo also measured a similar situation
> > where the latency gap between the two on Intel is even bigger.
> >
>
> Sandy Bridge doesn't have SYSCALL32 at all. It has SYSENTER and SYSCALL64.

Yeah, I was talking about SYSCALL in general.

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