perf: add threading capability to perfbdiff
Since we are releasing the GIL during diffing, it is interesting to see how a
thread pool would perform on diffing. We add a new `--threads` argument to
commands. Synchronizing the thread pool is a bit complex because we want to be
able to reuse it from one run to another.
On my computer (i7 with 4 cores + hyperthreading), I get the following data for
about 12000 revisions:
threads wall comb wall gain comb overhead
none 31.596715 31.59 0.00% 0.00%
1 31.621228 31.62 -0.08% 0.09%
2 16.406202 32.8 48.08% 3.83%
3 11.598334 34.76 63.29% 10.03%
4 9.205421 36.77 70.87% 16.40%
5 8.517604 42.51 73.04% 34.57%
6 7.94645 47.58 74.85% 50.62%
7 7.434972 51.92 76.47% 64.36%
8 7.070638 55.34 77.62% 75.18%
Compared to the feature disabled (threads=0), the overhead is negligible with
the threading code (threads=1), and the gain is already 48% with two threads.
SOURCES=$(notdir $(wildcard ../mercurial/help/*.[0-9].txt))
MAN=$(SOURCES:%.txt=%)
HTML=$(SOURCES:%.txt=%.html)
GENDOC=gendoc.py ../mercurial/commands.py ../mercurial/help.py \
../mercurial/help/*.txt ../hgext/*.py ../hgext/*/__init__.py
PREFIX=/usr/local
MANDIR=$(PREFIX)/share/man
INSTALL=install -c -m 644
PYTHON=python
RSTARGS=
export HGENCODING=UTF-8
all: man html
man: $(MAN)
html: $(HTML)
common.txt $(SOURCES) $(SOURCES:%.txt=%.gendoc.txt): $(GENDOC)
${PYTHON} gendoc.py "$(basename $@)" > $@.tmp
mv $@.tmp $@
%: %.txt %.gendoc.txt common.txt
$(PYTHON) runrst hgmanpage $(RSTARGS) --halt warning \
--strip-elements-with-class htmlonly $*.txt $*
%.html: %.txt %.gendoc.txt common.txt
$(PYTHON) runrst html $(RSTARGS) --halt warning \
--link-stylesheet --stylesheet-path style.css $*.txt $*.html
MANIFEST: man html
# tracked files are already in the main MANIFEST
$(RM) $@
for i in $(MAN) $(HTML); do \
echo "doc/$$i" >> $@ ; \
done
install: man
for i in $(MAN) ; do \
subdir=`echo $$i | sed -n 's/^.*\.\([0-9]\)$$/man\1/p'` ; \
mkdir -p "$(DESTDIR)$(MANDIR)"/$$subdir ; \
$(INSTALL) $$i "$(DESTDIR)$(MANDIR)"/$$subdir ; \
done
clean:
$(RM) $(MAN) $(HTML) common.txt $(SOURCES) $(SOURCES:%.txt=%.gendoc.txt) MANIFEST