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    SubjectRe: [PATCH 3/4] ring-buffer: add total count in ring-buffer-benchmark

    On Thu, 7 May 2009, Andrew Morton wrote:

    > On Fri, 08 May 2009 00:32:53 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
    >
    > > --- a/kernel/trace/ring_buffer_benchmark.c
    > > +++ b/kernel/trace/ring_buffer_benchmark.c
    > > @@ -285,6 +285,17 @@ static void ring_buffer_producer(void)
    > > avg = 1000000 / hit;
    > > pr_info("%ld ns per entry\n", avg);
    > > }
    > > +
    > > +
    >
    > s/\n\n/\n/

    My pinky must hae been itchy, and hit the enter twice.

    >
    > > + if (missed) {
    > > + if (time)
    > > + missed /= (long)time;
    > > +
    > > + pr_info("Total iterations per millisec: %ld\n", hit + missed);
    > > +
    > > + avg = 1000000 / (hit + missed);
    >
    > s/1000000/USEC_PER_SEC/?

    Heh, after I sent out the patch, I noticed that number, and thought to
    myself, "oh no, akpm is going to commont on that" ;-)

    >
    > Hopefully we can't have hit+missed==0.
    >
    > They're counters and hence should have unsigned types.
    >
    > But even unsigned up-counters can add to zero if wrapping occurs.

    Eigad! I never thought about an overflow to zero. Will fix.

    Thanks!

    -- Steve

    >
    >
    > > + pr_info("%ld ns per entry\n", avg);
    > > + }
    > > }
    >


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