Messages in this thread | | | Date | Tue, 2 Sep 2008 10:59:25 -0400 (EDT) | From | "CHADHA,VINEET" <> | Subject | Re: TLB evaluation for Linux |
| |
On Tue Sep 02 09:43:53 EDT 2008, Arjan van de Ven <arjan@infradead.org> wrote:
> On Tue, 2 Sep 2008 00:12:03 -0400 (EDT) > "CHADHA,VINEET" <vineet@ufl.edu> wrote: >
> note that linux only does an ipi to processors that actually are > currently running a thread of the same program (or a kernel > thread). > Old versions didn't do this (they also IPI'd idle processors), > but > on modern cpus and modern kernels that's not supposed to happen > anymore > (the C-states that flush the tlb anyway now do the kernel side > bookkeeping as well to avoid the wakeup+useless flush)
Interesting to know about it.
> one of the problems is that invlpg is rather expensive; in > long-ago > experiments the threshold was like around a handful of pages > already. > At that point.. all the bookkeeping isn't likely to be a win. > Esp since a tlb refill on x86 is quite cheap.
Yeah that is possible. Do you have link to any published work ? It would be still interesting to characterize and compare behavior for new workloads scenarios such as virtual machines.
| |