Re: [PATCH 4/6] trace: trace syscall in its handler not from ptrace handler

H. Peter Anvin
2012-03-29T22:48:54Z

On 03/29/2012 03:44 PM, David Sharp wrote:
>>
>> ANY increase to the fastpath is unacceptable, period.
>
> I think the last 4 ns would probably be eliminated if we could figure
> out how to call the inline function trace_sys_enter directly instead
> of through the out-of-line wrapper we had to add to work around the
> preprocessor magic.

I already told you how to do it... override the system call table entry.
There is a nice, juicy FUNCTION POINTER that we indirect through.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.