Re: [PATCH] Add FUTEX_CMP_REQUEUE futex op

[Rusty Russell <rusty@rustcorp.com.au>]

On Thu, 2004-05-20 at 19:38, Jakub Jelinek wrote:
> Hi!
> 
> FUTEX_REQUEUE operation has been added to the kernel mainly to improve
> pthread_cond_broadcast which previously used FUTEX_WAKE INT_MAX op.

For the record, I wasn't happy about adding FUTEX_REQUEUE to optimize
for suboptimal apps using the horrid pthreads interface, but I
understand the benchmarking realities.

I'm certainly way less than thrilled to discover that it doesn't work,
and we need to implement FUTEX_CMP_REQUEUE, and of course can't get rid
of FUTEX_REQUEUE.

The base futex concept and interface is simple (although the
implementation w/ the Linux mm subsystem proved interesting in the
corner cases); it's increasingly becoming a horror with these kind of
hacks.

8(
Rusty.
-- 
Anyone who quotes me in their signature is an idiot -- Rusty Russell