Messages in this thread | | | Date | Tue, 6 Apr 2010 14:51:28 +0100 | From | Alan Cox <> | Subject | Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional adaptive spinning |
| |
On Tue, 06 Apr 2010 15:35:31 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> On Tue, 2010-04-06 at 16:28 +0300, Avi Kivity wrote: > > > > Yes, but that's the best case for spinning. You could simply use a > > userspace spinlock in this case. > > Userspace spinlocks are evil.. they should _never_ be used.
Thats a gross and inaccurate simplification. For the case Avi is talking about spinning in userspace makes sense in a lot of environments. Once you've got one thread pinned per cpu (or gang scheduling >-) ) there are various environments where it makes complete and utter sense.
| |