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    SubjectRe: [RFC] Proposal for ptrace improvements
    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@kernel.org> 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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