On Fri, 23 Mar 2007 11:32:44 +0100 Nick Piggin <[EMAIL PROTECTED]> wrote:
> On Fri, Mar 23, 2007 at 11:04:18AM +0100, Ingo Molnar wrote: > > > > * Nick Piggin <[EMAIL PROTECTED]> wrote: > > > > > Implement queued spinlocks for i386. [...] > > > > isnt this patented by MS? (which might not worry you SuSE/Novell guys, > > but it might be a worry for the rest of the world ;-) > > Hmm, it looks like they have implemented a system where the spinning > cpu sleeps on a per-CPU variable rather than the lock itself, and > the releasing cpu writes to that variable to wake it. They do this > so that spinners don't continually perform exclusive->shared > transitions on the lock cacheline. They call these things queued > spinlocks. They don't seem to be very patent worthy either, but > maybe it is what you're thinking of? > > I'm not as concerned about the contended performance of spinlocks > for Linux as MS seems to be for windows (they seem to be very proud > of this lock). Because if it is a big problem then IMO it is a bug. > > This was just something I had in mind when the hardware lock > starvation issue came up, so I thought I should quickly code it up > and RFC... actually it makes contended performance worse, but I'm > not too worried about that because I'm happy I was able to implement > it without increasing data size or number of locked operations. Sure, but please note that you should rename your patch to : "Implement queued spinlocks for i486" :) - 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/
