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

[Hugh Dickins <hugh@veritas.com>]

On Sun, 3 Jul 2005, Arjan van de Ven wrote:
> 
> hmm. I wonder if a slightly different approach (based on the __slow)
> idea would make sense
> 1) Use -ffunction-sections option from gcc to put each function in it's
> own section
> 2) Use readprofile/oprofile data to collect an (external to the code)
> list of hot/cold functions (we can put a default list in the kernel
> source somewhere and allow people to measure their own if they want)
> 3) Use this list to make a linker script to order the functions
> 
> this way we don't need to put a lot of __slow's in the code *and* it's
> based on measurements not assumptions, and can be tuned for a specific
> situation in addition.

This is reminiscent of "fur", whose source Old SCO opened.
Google for SCO fur: amidst all the hits about "fur flying"
you might find something useful!

Hugh