Hello Wouter,
Wouter Verhelst <[EMAIL PROTECTED]> wrote:
> On Fri, May 19, 2006 at 04:49:49PM +0200, Olaf van der Spek wrote:
>> On 5/19/06, Wouter Verhelst <[EMAIL PROTECTED]> wrote:
>> Why would they have to work with dash?
>
> If the difference in speed is indeed that insane, that's nice.
>
> I've received a bugreport with patch against the nbd packages now which
> implement whatever it's doing now with eval rather than bash arrays. Now
> I'm not sure whether this is actually going to be any faster (eval might
> require more processing time than arrays?),
Do you search something like this:
% /usr/bin/time dash -c 'i=0; while [ $i -lt 10000 ]; do \
eval test -n "\$foo_$i"; i=$(($i+1)); done'
0.50user 0.00system 0:00.52elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+202minor)pagefaults 0swaps
% /usr/bin/time bash -c 'i=0; while [ $i -lt 10000 ]; do \
test -n ${foo[$i]}; i=$(($i+1)); done'
1.54user 0.04system 0:01.59elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+518minor)pagefaults 0swaps
But I would not weight this comparison to high. This tests only a
_part_ of the init script.
But what counts more in the comparison dash vs. bash is the shell
startup. And the shell is started for every script not name foo.sh.
% /usr/bin/time dash -c 'i=0; while [ $i -lt 100 ]; do \
/bin/bash -c true; i=$(($i+1)); done'
1.13user 0.53system 0:01.68elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+43209minor)pagefaults 0swaps
% /usr/bin/time dash -c 'i=0; while [ $i -lt 100 ]; do \
/bin/dash -c true; i=$(($i+1)); done'
0.13user 0.19system 0:00.32elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+19309minor)pagefaults 0swaps
Some more shells:
% /usr/bin/time dash -c 'i=0; while [ $i -lt 100 ]; do \
/bin/zsh -c true; i=$(($i+1)); done'
1.56user 0.65system 0:02.23elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+50709minor)pagefaults 0swaps
% /usr/bin/time dash -c 'i=0; while [ $i -lt 100 ]; do \
/bin/posh -c true; i=$(($i+1)); done'
0.14user 0.25system 0:00.75elapsed 53%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (1major+20208minor)pagefaults 0swaps
Bye, Jörg.
--
Der kommt den Göttern am nächsten, der auch dann schweigen kann,
wenn er im Recht ist. (Cato; 234-149 v. Chr.)
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