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

Steven Rostedt
2009-05-08T10:52:50Z

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);
> > + }
> > }
>