On Sat, 2012-09-15 at 19:08 +0200, richard -rw- weinberger wrote: > On Sat, Sep 15, 2012 at 6:36 PM, Mike Galbraith <efa...@gmx.de> wrote: > >> Just using futex is unfortunately not the answer either. > > > > Yes, postgress performs loads better with it's spinlocks, but due to > > that, it necessarily _hates_ preemption. How the is the scheduler > > supposed to know that any specific userland task _really_ shouldn't be > > preempted at any specific time, else bad things follow? > > Why perform custom userspace spinlocks better than futex() based ones? > I thought we have futex() to get rid of the custom ones... > Makes futex() only sense when things like priority inheritance are needed?
Dunno. Likely because data doesn't go cold when you spin a bit, but go to sleep and the next guy may stomp cache flat with size XXL boots. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
