Re: [RFC] Proposal for ptrace improvements

[Tejun Heo]

On Fri, Mar 04, 2011 at 03:31:15PM +0100, Denys Vlasenko wrote:
> On Fri, Mar 4, 2011 at 3:07 PM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> > Hello,
> >
> > On Fri, Mar 04, 2011 at 02:59:32PM +0100, Denys Vlasenko wrote:
> >> I would rather speed strace up than slow it down further, even if
> >> slightly.
> >
> > The question to ask is at what cost?  If mostly unnoticeable slow down
> > makes the API cleaner, I'll go that way.  Everything is a tradeoff.
> 
> # time sh -c 'ls -lR /usr/share >/dev/null'
> real	0m2.633s
>
> strace without PTRACE_GETSIGINFO:
> real	0m47.023s
> real	0m48.799s
> real	0m47.695s
>
> strace with PTRACE_GETSIGINFO:
> real	0m51.958s
> real	0m53.773s
> real	0m51.625s

Great, numbers, so it's ~10 slow down.  Gees, with or without that
change, strace(2) is heavy, >18 times slower than without.  Maybe it
should give up on ptrace and use the new tracing infrastructure?

Anyways, thanks a lot for the numbers.  Much appreciated.

-- 
tejun
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