On Thu, Mar 29, 2007 at 10:06:41PM -0400, Lee Revell wrote: > On 3/29/07, Davide Libenzi <davidel@xmailserver.org> wrote: > >On Thu, 29 Mar 2007, Oleg Nesterov wrote: > > > >> On 03/28, Nick Piggin wrote: > >> > > >> > Well with my queued spinlocks, all that lockbreak stuff can just come > >out > >> > of the spin_lock, break_lock out of the spinlock structure, and > >> > need_lockbreak just becomes (lock->qhead - lock->qtail > 1). > >> > >> Q: queued spinlocks are not CONFIG_PREEMPT friendly, > > > >Why? Is CONFIG_PREEMPT friendly to anyone? :) > > Until someone fixes all the places in the kernel where scheduling can > be held off for tens of milliseconds, CONFIG_PREEMPT will be an > absolute requirement for many applications like audio and gaming.
There's nothing wrong with CONFIG_PREEMPT for those users. We have a few other performance concessions activated with CONFIG_PREEMPT on. I think a usual upper of a few miliseconds (especially for SMP) is reasonable for a non preempt kernel. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
