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Re: [PATCH] extend svn_subst_translate_string() to record whether re-encoding and/or line ending translation were performed (v. 2)

From: Danny Trebbien <dtrebbien_at_gmail.com>
Date: Sun, 28 Nov 2010 08:00:04 -0800

> I timed 'svn export' of a 146MB subdirectory of a format-21 working
> copy to a linux tmpfs.  Below, 't1' is pristine trunk_at_HEAD and 't2' is
> trunk_at_HEAD plus the patch at the top of this thread:
>
> % cd /tmp/ram
> % mount | grep $PWD
> tmpfs on /tmp/ram type tmpfs (rw,nosuid,nodev,noatime)
> % rm -f /tmp/five-{t1,t2}
> % for j in $(seq 5); do
>   for ii in t1 t2; do
>    .svn $ii;
>    rm -rf ./$ii;
>    (time $svn export -q ~/src/asf/infra/trunk/ ./$ii) 2>&1 | tee -a ../five-$ii;
>    rm -rf ./$ii;
>   done;
>  done
> % cat /tmp/five-t1
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.26s user 2.36s system 37% cpu 15.035 total
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.29s user 2.58s system 29% cpu 20.046 total
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.41s user 2.36s system 29% cpu 19.664 total
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.36s user 2.45s system 30% cpu 19.222 total
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.32s user 2.39s system 29% cpu 19.156 total
> % cat /tmp/five-t2
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.40s user 2.35s system 32% cpu 17.823 total
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.51s user 2.64s system 26% cpu 22.859 total
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.26s user 2.49s system 29% cpu 19.313 total
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.28s user 2.37s system 29% cpu 19.312 total
> $svn export -q ~/src/asf/infra/trunk/ ./$ii  3.24s user 2.30s system 28% cpu 19.329 total
> %
>
> It seems that the second set of results is slightly slower?
>
> Daniel

Using R 2.12.0 I ran a two-sample unpaired t-test of the totals. The
alternative hypothesis is that the mean time to run `five-t1` (μ_t1)
is less than the mean time to run `five-t2` (μ_t2):

> x <- c(15.035, 20.046, 19.664, 19.222, 19.156)
> y <- c(17.823, 22.859, 19.313, 19.312, 19.329)
> t.test(x, y, alternative = "less", var.equal = TRUE, conf.level = 0.90)

        Two Sample t-test

data: x and y
t = -0.892, df = 8, p-value = 0.1992
alternative hypothesis: true difference in means is less than 0 (μ_t1
- μ_t2 < 0)
90 percent confidence interval:
     -Inf 0.624089
sample estimates:
mean of x mean of y
  18.6246 19.7272

So actually we "fail to reject the null hypothesis", meaning that we
cannot reject the claim that μ_t1 >= μ_t2.

`five-t2` should be taking longer than `five-t1` because we know that
`five-t2` does more work than `five-t1`. However, the difference is
so small that we have trouble telling the timings apart.
Received on 2010-11-28 17:00:45 CET

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