Re: [RFC] exit_thread() speedups in x86 process.c

[Coywolf Qi Hunt <coywolf@gmail.com>]

On 6/14/05, cutaway@bellsouth.net <cutaway@bellsouth.net> wrote:
> In the current exit_thread() implementation, it appears including the I/O
> port map tear down code within the exit_thread() generates enough autovar
> data that the compiler needs to spill 4 registers to the stack resulting in
> (4) PUSH on entry and (4) POP on exit.
> 
> When I tried extracting the map teardown into a seperate function, the
> situation changed dramatically to where NO REGISTERS were being
> pushed/popped in the normal path entry/exit.
> 
> Below is the original generated code, code my proposal generated, and an
> #ifdef'd change that produced this elimination of the PUSH/POP's.
> 
> Unless I'm on drugs, this looks like a solid winner in a fairly important
> code path :)


I see the effect, But I think it would be better to leave the job to
gcc to generate better code for unlikely, imho.

-- 
Coywolf Qi Hunt
http://ahbl.org/~coywolf/