Re: [PATCH][2.6] Allow x86_64 to reenable interrupts on contention

Zwane Mwaikambo
2004-07-27T14:28:00Z

On Tue, 27 Jul 2004, Andi Kleen wrote:

> On Tue, 27 Jul 2004 05:29:10 -0400 (EDT)
> Zwane Mwaikambo <zwane@linuxpower.ca> wrote:
>
> > This is a follow up to the previous patches for ia64 and i386, it will
> > allow x86_64 to reenable interrupts during contested locks depending on
> > previous interrupt enable status. It has been runtime and compile tested
> > on UP and 2x SMP Linux-tiny/x86_64.
>
> This will likely increase code size. Do you have numbers by how much? And is it
> really worth it?

Yes there is a growth;

text data bss dec hex filename
3655358 1340511 486128 5481997 53a60d vmlinux-after
3648445 1340511 486128 5475084 538b0c vmlinux-before

And this was on i386;

text data bss dec hex filename
2628024 921731 0 3549755 362a3b vmlinux-after
2621369 921731 0 3543100 36103c vmlinux-before

Keith Owens managed to get increased throughput as the original patch was
driven by poor performance from a workload. I think it's worth it just for
the reduced interrupt latency, the code size issue can also be taken care
of, but that requires benchmarking as the change is a bit more drastic.