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    SubjectRe: [RFC] Proposal for ptrace improvements
    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
    user 0m0.540s
    sys 0m2.047s

    strace without PTRACE_GETSIGINFO:

    # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null'
    exit_group(0) = ?
    real 0m47.023s
    user 0m3.843s
    sys 0m29.050s
    # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null'
    exit_group(0) = ?
    real 0m48.799s
    user 0m3.808s
    sys 0m29.736s
    # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null'
    exit_group(0) = ?
    real 0m47.695s
    user 0m3.965s
    sys 0m29.047s

    strace with PTRACE_GETSIGINFO:

    # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null'
    exit_group(0) = ?
    real 0m51.958s
    user 0m3.899s
    sys 0m31.584s
    # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null'
    exit_group(0) = ?
    real 0m53.773s
    user 0m3.920s
    sys 0m29.713s
    # time sh -c './strace -e trace=exit_group ls -lR /usr/share >/dev/null'
    exit_group(0) = ?
    real 0m51.625s
    user 0m3.961s
    sys 0m30.970s

    --
    vda
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