Re: [PATCH] idle using PNI monitor/mwait

[Linus Torvalds]

On Tue, 8 Jul 2003, Nakajima, Jun wrote:
> 
> Attached is a patch that enables PNI (Prescott New Instructions)
> monitor/mwait in kernel idle (opcodes are now public). Basically MWAIT
> is similar to hlt, but you can avoid IPI to wake up the processor
> waiting. A write (by another processor) to the address range specified
> by MONITOR would wake up the processor waiting on MWAIT.

How about spinlocks? Does it make sense to make the contention code use 
mwait too, or are the latencies too high? Not that we have a lot of 
high-contention locks any more, so maybe it doesn't much matter.

Also, wasn't there some flag to set the "mwait" granularity? I don't see 
anything like that in the patch..

		Linus