On Apr 4, 2007, at 2:40 PM, Andrew Doran wrote:

> Some numbers from a pmax GENERIC kernel below. If we were to stop  
> passing
> "struct lwp *" about then it looks like there are some savings to  
> be had.
>
> => with s7 as a general purpose register
>
> -rwxr-xr-x  1 ad  staff  3781432 Apr  4 14:28 netbsd
>
> objdump -d netbsd | grep s7 | wc -l
>       99
>
> => with s7 as curlwp
>
> -rwxr-xr-x  1 ad  staff  3778945 Apr  4 14:19 netbsd
>
> objdump -d netbsd | grep s7 | wc -l
>      573

Cool.  BTW, if we do this, it might be good to #ifdef _KERNEL out the  
s7 definition and call it curlwp_reg, or something like that, to make  
it harder to use it by mistake in asm code.

-- thorpej