Looking for speed increases in "make index" and pkg_version for ports

[Peter Jeremy]

On 2007-May-27 15:30:48 -0700, Jeremy Chadwick <koitsu at freebsd.org> wrote:
>This sounds like a good solution.  In fact, I'm lead to believe that
>heavy reliance on /bin/sh is part of why the ports collection is slow.

Someone needs to enable accounting on a recent -current (with the
high-resolution accounting records) and look at where the time is
actually going.  (My -current box needs upgrading before I could
do this).

That said, /bin/sh is dynamically linked and a fork/exec is not cheap.
Some quick-and-not-necessarily-reliable tests on 6.2-STABLE/amd64 show
that /bin/sh takes about 2.5 times as long to start as /rescue/sh
(though it's only 2:1 on i386).  (These are different boxes so the
absolute times aren't comparable).

amd64% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >/dev/null
sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >   0.20s user 0.08s system 98% cpu 0.283 total
amd64% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >/dev/null 
sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >   0.22s user 0.06s system 97% cpu 0.287 total
amd64% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >/dev/null
sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >   0.19s user 0.10s system 98% cpu 0.288 total
amd64% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); /rescue/sh -c "echo foo"; done' >/dev/null
sh -c  > /dev/null  0.84s user 6.12s system 97% cpu 7.162 total
amd64% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); /rescue/sh -c "echo foo"; done' >/dev/null
sh -c  > /dev/null  1.12s user 6.05s system 97% cpu 7.366 total
amd64% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); /bin/sh -c "echo foo"; done' >/dev/null
sh -c  > /dev/null  5.72s user 13.40s system 96% cpu 19.734 total
amd64% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); /bin/sh -c "echo foo"; done' >/dev/null 
sh -c  > /dev/null  5.97s user 12.89s system 97% cpu 19.407 total
amd64%   

i386% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >/dev/null
sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >   0.17s user 0.03s system 95% cpu 0.208 total
i386% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >/dev/null
sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >   0.17s user 0.03s system 99% cpu 0.199 total
i386% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >/dev/null
sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); echo foo; done' >   0.16s user 0.04s system 99% cpu 0.200 total
i386% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); /rescue/sh -c "echo foo"; done' >/dev/null
sh -c  > /dev/null  3.68s user 18.19s system 98% cpu 22.212 total
i386% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); /rescue/sh -c "echo foo"; done' >/dev/null
sh -c  > /dev/null  3.34s user 18.54s system 98% cpu 22.110 total
i386% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); /bin/sh -c "echo foo"; done' >/dev/null 
sh -c  > /dev/null  12.03s user 29.42s system 98% cpu 41.965 total
i386% time sh -c 'i=0; while [ $i -lt 10000 ]; do i=$(($i+1)); /bin/sh -c "echo foo"; done' >/dev/null
sh -c  > /dev/null  12.20s user 29.25s system 98% cpu 41.975 total

-- 
Peter Jeremy
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