On Tue, Nov 9, 2010 at 08:33, Johannes Sixt <j.sixt@xxxxxxxxxxxxx> wrote:
> Am 11/8/2010 23:39, schrieb Ãvar ArnfjÃrà Bjarmason:
>> Â Â eval_gettext () {
>> Â Â Â gettext "$1" | (export PATH `envsubst --variables "$1"`; envsubst "$1")
>> Â Â }
>
> So, for every message printed, you have at least 3 fork()s (usually even
> more)! I'm not happy about that. You *must* avoid this at least for
> NO_GETTEXT builds, but if you can reduce them even for no-NO_GETTEXT
> builds, it would be great.
Why is that a "*must*"? For the GNU gettext versions (our will be
faster, if anything):
$ time (for i in {1..1000}; do gettext "foobar"; done) >/dev/null
real 0m3.219s
user 0m0.253s
sys 0m2.570s
$ time (for i in {1..1000}; do eval_gettext "foobar"; done) >/dev/null
real 0m12.615s
user 0m1.264s
sys 0m12.384s
So that's around 0.003 seconds and 0.01 seconds per message for
gettext() and eval_gettext() respectively.
I'm not indifferent to that slight cost, but (almost?) all of the
eval_gettext messages we have are just printing out an error message
before we die. None of them are inside a tight loop. This is the
typical use case:
git-am.sh: eval_gettext "When you have resolved this problem
run \"\$cmdline --resolved\".
git-am.sh: clean_abort "$(eval_gettext "Patch
format \$patch_format is not supported.")"
git-am.sh: die "$(eval_gettext "previous rebase directory
\$dotest still exists but mbox given.")"
git-am.sh: die "$(eval_gettext "Dirty index: cannot
apply patches (dirty: \$files)")"
git-am.sh: eval_gettext "Patch is empty. Was
it split wrong?
git-am.sh: say "$(eval_gettext "Applying: \$FIRSTLINE")"
git-am.sh: eval_gettext 'Patch failed at $msgnum
$FIRSTLINE'; echo
git-bisect.sh: die "$(eval_gettext "'\$arg' does
not appear to be a valid revision")"
git-bisect.sh: *) die "$(eval_gettext "Bad
bisect_write argument: \$state")" ;;
git-bisect.sh: revs=$(git rev-list "$arg") || die
"$(eval_gettext "Bad rev input: \$arg")" ;;
git-bisect.sh: die "$(eval_gettext "Bad
rev input: \$rev")"
git-bisect.sh: die "$(eval_gettext "'\$invalid' is not a
valid commit")"
git-bisect.sh: test -r "$file" || die "$(eval_gettext "cannot
read \$file for replaying")"
git-bisect.sh: eval_gettext "running \$command"; echo
git-bisect.sh: echo >&2 "$(eval_gettext "bisect run failed:
git-bisect.sh: echo >&2 "$(eval_gettext "bisect run failed:
The cost for that is going to be much less than the time we spend on
forking out to sed, grep and other similar utilities inside our shell
scripts. If eval_gettext() is slowing things down noticeably that's
probably a sign that we need to rewrite the script in C, not
micro-optimize the eval_gettext() implementation.
But maybe you have reason to think otherwise? I haven't noticed any
noticable slowdowns from doing it this way, but maybe I've been
looking at the wrong thing.
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