Messages in this thread | | | Date | Sat, 27 Jun 2009 19:28:54 +0200 | From | Ingo Molnar <> | Subject | Re: performance counter ~0.4% error finding retired instruction count |
| |
* Paul Mackerras <paulus@samba.org> wrote:
> Ingo Molnar writes: > > > I measured 2000, but generally a few thousand cycles per > > invocation sounds about right. > > We could actually do a bit better than we do, fairly easily. We > could attach the counters to the child after the fork instead of > the parent before the fork, using a couple of pipes for > synchronization. And there's probably a way to get the dynamic > linker to resolve the execvp call early in the child so we avoid > that overhead. I think we should be able to get the overhead down > to tens of userspace instructions without doing anything > unnatural.
Definitely so.
Ingo
| |