From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: system call time increase when turning on CONFIG_PARAVIRT
Date: Wed, 07 Mar 2007 16:02:04 -0800
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To: Jeremy Fitzhardinge <jeremy@goop.org>, zach@vmware.com
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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