Messages in this thread | | | Subject | Re: [PATCH v2 1/2] mm/slub: optimize alloc/free fastpath by removing preemption on/off | From | Eric Dumazet <> | Date | Fri, 16 Jan 2015 05:40:59 -0800 |
| |
On Thu, 2015-01-15 at 23:07 -0500, Steven Rostedt wrote: > On Thu, 15 Jan 2015 21:57:58 -0600 (CST) > Christoph Lameter <cl@linux.com> wrote: > > > > I get: > > > > > > mov %gs:0x18(%rax),%rdx > > > > > > Looks to me that %gs is used. > > > > %gs is used as a segment prefix. That does not add significant cycles. > > Retrieving the content of %gs and loading it into another register > > would be expensive in terms of cpu cycles. > > OK, maybe that's what I saw in my previous benchmarks. Again, that was > a while ago.
I made same observation about 3 years ago, on old cpus.
| |