Re: [PATCH v2 08/10] x86-64: Emulate vsyscalls

From: Ingo Molnar
Date: Mon May 30 2011 - 04:07:39 EST



* Jan Beulich <JBeulich@xxxxxxxxxx> wrote:

> >>> On 30.05.11 at 05:48, Andy Lutomirski <luto@xxxxxxx> wrote:
> > This causes vsyscalls to be a little more expensive than real
> > syscalls. Fortunately sensible programs don't use them.
>
> Hmm - weren't vsyscalls there for performance reasons?

New code uses the vDSO. The fixed-address vsyscalls are apparently
only used in esoteric cases like statically linked glibc binaries.
(which should arguably be using the vDSO as well)

Thanks,

Ingo
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