Re: system call time increase when turning on CONFIG_PARAVIRT

From: Tim Chen
Date: Wed Mar 07 2007 - 19:53:49 EST


On Fri, 2007-03-02 at 16:16 -0800, Jeremy Fitzhardinge wrote:

>
> Yes, the intent is that running a CONFIG_PARAVIRT kernel on native
> hardware will have negligible performance hit compared to running a
> non-paravirt kernel.
>
> J

It turned out that VDSO was turned off by CONFIG_PARAVIRT option,
causing the system call to use inefficient int 0x80 which led to the
increase system_call time I was seeing. I noted that Ingo has caught
this problem and proposed a patch to correct this issue in another mail
thread.

Tim
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