On Tue, 2013-05-21 at 19:55 +0100, Richard Sandiford wrote:
> Hmm, but generic.md is very much legacy and shouldn't be used for
> vaguely modern cores. Even something like -mips32 is supposed to avoid
> the generic scheduler; it should use the 4k scheduler instead.
> What options were you using to trigger it?
I am just doing a default compilation of my mips-mti-linux-gnu target.
This defaults to mips32r2. I just tried adding -mtune=mips32r2 and that
made no difference, -mtune=4k also makes no difference, but -mtune=4kc
does affect the output.
> It might be worth having a new "generic" scheduler that's supposed to be
> a good compromise for modern cores though. Or, more simply, we could just
> change:
>
> MIPS_CPU ("mips32", PROCESSOR_4KC, 32, PTF_AVOID_BRANCHLIKELY)
> MIPS_CPU ("mips32r2", PROCESSOR_M4K, 33, PTF_AVOID_BRANCHLIKELY)
> MIPS_CPU ("mips64", PROCESSOR_5KC, 64, PTF_AVOID_BRANCHLIKELY)
> /* ??? For now just tune the generic MIPS64r2 for 5KC as well. */
> MIPS_CPU ("mips64r2", PROCESSOR_5KC, 65, PTF_AVOID_BRANCHLIKELY)
>
> to tune for other processors instead, if you don't think 4kc, etc. are
> representative enough.
Hm, I think the problem may be that mips32r2 defaults to PROCESSOR_M4K
and mips32 defaults to PROCESSOR_4KC. I don't see any special scheduler
for m4k. Is there supposed to be a scheduler for m4k?
Steve Ellcey
