On Sat, May 09, 2015 at 06:07:18AM +0100, Pádraig Brady wrote:
> On 08/05/15 14:26, Alexey Dobriyan wrote:
> > exuberant()
> > {
> > - all_target_sources | xargs $1 -a \
> > + rm -f .make-tags.*
> > +
> > + all_target_sources >.make-tags.src
> > + NR_CPUS=$(getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1)
>
> `nproc` is simpler and available since coreutils 8.1 (2009-11-18)
nproc was discarded because getconf is standartized.
> > + NR_LINES=$(wc -l <.make-tags.src)
> > + NR_LINES=$((($NR_LINES + $NR_CPUS - 1) / $NR_CPUS))
> > +
> > + split -a 6 -d -l $NR_LINES .make-tags.src .make-tags.src.
>
> `split -d -nl/$(nproc)` is simpler and available since coreutils 8.8
> (2010-12-22)
-nl/ can't count and always make first file somewhat bigger, which is
suspicious. What else it can't do right?
> > + sort .make-tags.* >>$2
> > + rm -f .make-tags.*
>
> Using sort --merge would speed up significantly?
By ~1 second, yes.
> Even faster would be to get sort to skip the header lines, avoiding the need
> for sed.
> It's a bit awkward and was discussed at:
> http://lists.gnu.org/archive/html/coreutils/2013-01/msg00027.html
> Summarising that, is if not using merge you can:
>
> tlines=$(($(wc -l < "$2") + 1))
> tail -q -n+$tlines .make-tags.* | LC_ALL=C sort >>$2
>
> Or if merge is appropriate then:
>
> tlines=$(($(wc -l < "$2") + 1))
> eval "eval LC_ALL=C sort -m '<(tail -n+$tlines
> .make-tags.'{1..$(nproc)}')'" >>$2
Might as well teach ctags to do real parallel processing.
LC_* are set by top level Makefile.
> p.p.s. You may want to `trap EXIT cleanup` to rm -f .make-tags.*
The real question is how to kill ctags reliably.
Naive
trap 'kill $(jobs -p); rm -f .make-tags.*' TERM INT
doesn't work.
Files are removed, but processes aren't.
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