Messages in this thread Patch in this message | | | Subject | RE: lmbench results for 2.4 and 2.5 -- updated results | Date | Mon, 24 Mar 2003 12:11:52 -0800 | From | "Nakajima, Jun" <> |
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I don't think it's measuring anything useful at this point, especially with the cost of start(0) and stop(0,0) (they are eventually gettimeofday(), as far as I looked at the code) are substantial compared to page fault (sum += *end;) itself. If you move them outside the while loop, I think it's beter.
void timeit(char *file, char *where, int size) { char *end = where + size - 16*1024; int sum = 0; int n = 0, usecs = 0;
while (end > where) { start(0); sum += *end; end -= 256*1024; usecs += stop(0,0); n++; } use_int(sum); fprintf(stderr, "Pagefaults on %s: %d usecs\n", file, usecs/n);
> -----Original Message----- > From: Larry McVoy [mailto:lm@bitmover.com] > Sent: Monday, March 24, 2003 12:01 PM > To: Pallipadi, Venkatesh > Cc: linux-kernel@vger.kernel.org; Linus Torvalds > Subject: Re: lmbench results for 2.4 and 2.5 -- updated results > > On Mon, Mar 24, 2003 at 11:53:44AM -0800, Pallipadi, Venkatesh wrote: > > --- LMbench/src/lat_pagefault.c.org Mon Mar 24 10:40:46 2003 > > +++ LMbench/src/lat_pagefault.c Mon Mar 24 10:54:34 2003 > > @@ -67,5 +67,5 @@ > > n++; > > } > > use_int(sum); > > - fprintf(stderr, "Pagefaults on %s: %d usecs\n", file, usecs/n); > > + fprintf(stderr, "Pagefaults on %s: %f usecs\n", file, (1.0 * > > usecs) / n); > > } > > It's been a long time since I've looked at this benchmark, has anyone > stared at it and do you believe it measures anything useful? If not, > I'll drop it from a future release. If I remember correctly what I > was trying to do was to measure the cost of setting up the mapping > but I might be crackin smoke. > -- > --- > Larry McVoy lm at bitmover.com > http://www.bitmover.com/lm > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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