Makefile

worker: change partition strategy to every Nth element

The only consumer of the worker pool code today is `hg update`.

Previously, the algorithm to partition work to each worker process
preserved input list ordering. We'd take the first N elements, then
the next N elements, etc. Measurements on mozilla-central demonstrate
this isn't an optimal partitioning strategy.

I added debug code to print when workers were exiting. When performing
a working copy update on a previously empty working copy of
mozilla-central, I noticed that process lifetimes were all over the
map. One worker would complete after 7s. Many would complete after
12s. And another worker would often take >16s. This behavior occurred
for many worker process counts and was more pronounced on some than
others.

What I suspect is happening is some workers end up with lots of
small files and others with large files. This is because the update
code passes in actions according to sorted filenames. And, directories
under tend to accumulate similar files. For example, test directories
often consist of many small test files and media directories contain
binary (often larger) media files.

This patch changes the partitioning algorithm to select every Nth
element from the input list. Each worker thus has a similar composition
of files to operate on.

The result of this change is that worker processes now all tend to exit
around the same time. The possibility of a long pole due to being
unlucky and receiving all the large files has been mitigated. Overall
execution time seems to drop, but not by a statistically significant
amount on mozilla-central. However, repositories with directories
containing many large files will likely show a drop.

There shouldn't be any regressions due to partial manifest decoding
because the update code already iterates the manifest to determine
what files to operate on, so the manifest should already be decoded.

# If you want to change PREFIX, do not just edit it below. The changed
# value wont get passed on to recursive make calls. You should instead
# override the variable on the command like:
#
# % make PREFIX=/opt/ install

PREFIX=/usr/local
export PREFIX
PYTHON=python
$(eval HGROOT := $(shell pwd))
HGPYTHONS ?= $(HGROOT)/build/pythons
PURE=
PYFILES:=$(shell find mercurial hgext doc -name '*.py')
DOCFILES=mercurial/help/*.txt
export LANGUAGE=C
export LC_ALL=C
TESTFLAGS ?= $(shell echo $$HGTESTFLAGS)

# Set this to e.g. "mingw32" to use a non-default compiler.
COMPILER=

help:
	@echo 'Commonly used make targets:'
	@echo '  all          - build program and documentation'
	@echo '  install      - install program and man pages to $$PREFIX ($(PREFIX))'
	@echo '  install-home - install with setup.py install --home=$$HOME ($(HOME))'
	@echo '  local        - build for inplace usage'
	@echo '  tests        - run all tests in the automatic test suite'
	@echo '  test-foo     - run only specified tests (e.g. test-merge1.t)'
	@echo '  dist         - run all tests and create a source tarball in dist/'
	@echo '  clean        - remove files created by other targets'
	@echo '                 (except installed files or dist source tarball)'
	@echo '  update-pot   - update i18n/hg.pot'
	@echo
	@echo 'Example for a system-wide installation under /usr/local:'
	@echo '  make all && su -c "make install" && hg version'
	@echo
	@echo 'Example for a local installation (usable in this directory):'
	@echo '  make local && ./hg version'

all: build doc

local:
	$(PYTHON) setup.py $(PURE) \
	  build_py -c -d . \
	  build_ext $(COMPILER:%=-c %) -i \
	  build_hgexe $(COMPILER:%=-c %) -i \
	  build_mo
	env HGRCPATH= $(PYTHON) hg version

build:
	$(PYTHON) setup.py $(PURE) build $(COMPILER:%=-c %)

wheel:
	FORCE_SETUPTOOLS=1 $(PYTHON) setup.py $(PURE) bdist_wheel $(COMPILER:%=-c %)

doc:
	$(MAKE) -C doc

clean:
	-$(PYTHON) setup.py clean --all # ignore errors from this command
	find contrib doc hgext i18n mercurial tests \
		\( -name '*.py[cdo]' -o -name '*.so' \) -exec rm -f '{}' ';'
	rm -f $(addprefix mercurial/,$(notdir $(wildcard mercurial/pure/[a-z]*.py)))
	rm -f MANIFEST MANIFEST.in hgext/__index__.py tests/*.err
	if test -d .hg; then rm -f mercurial/__version__.py; fi
	rm -rf build mercurial/locale
	$(MAKE) -C doc clean

install: install-bin install-doc

install-bin: build
	$(PYTHON) setup.py $(PURE) install --root="$(DESTDIR)/" --prefix="$(PREFIX)" --force

install-doc: doc
	cd doc && $(MAKE) $(MFLAGS) install

install-home: install-home-bin install-home-doc

install-home-bin: build
	$(PYTHON) setup.py $(PURE) install --home="$(HOME)" --prefix="" --force

install-home-doc: doc
	cd doc && $(MAKE) $(MFLAGS) PREFIX="$(HOME)" install

MANIFEST-doc:
	$(MAKE) -C doc MANIFEST

MANIFEST.in: MANIFEST-doc
	hg manifest | sed -e 's/^/include /' > MANIFEST.in
	echo include mercurial/__version__.py >> MANIFEST.in
	sed -e 's/^/include /' < doc/MANIFEST >> MANIFEST.in

dist:	tests dist-notests

dist-notests:	doc MANIFEST.in
	TAR_OPTIONS="--owner=root --group=root --mode=u+w,go-w,a+rX-s" $(PYTHON) setup.py -q sdist

check: tests

tests:
	cd tests && $(PYTHON) run-tests.py $(TESTFLAGS)

test-%:
	cd tests && $(PYTHON) run-tests.py $(TESTFLAGS) $@

testpy-%:
	@echo Looking for Python $* in $(HGPYTHONS)
	[ -e $(HGPYTHONS)/$*/bin/python ] || ( \
	cd $$(mktemp --directory --tmpdir) && \
        $(MAKE) -f $(HGROOT)/contrib/Makefile.python PYTHONVER=$* PREFIX=$(HGPYTHONS)/$* python )
	cd tests && $(HGPYTHONS)/$*/bin/python run-tests.py $(TESTFLAGS)

check-code:
	hg manifest | xargs python contrib/check-code.py

update-pot: i18n/hg.pot

i18n/hg.pot: $(PYFILES) $(DOCFILES) i18n/posplit i18n/hggettext
	$(PYTHON) i18n/hggettext mercurial/commands.py \
	  hgext/*.py hgext/*/__init__.py \
	  mercurial/fileset.py mercurial/revset.py \
	  mercurial/templatefilters.py mercurial/templatekw.py \
	  mercurial/templater.py \
	  mercurial/filemerge.py \
	  mercurial/hgweb/webcommands.py \
	  $(DOCFILES) > i18n/hg.pot.tmp
        # All strings marked for translation in Mercurial contain
        # ASCII characters only. But some files contain string
        # literals like this '\037\213'. xgettext thinks it has to
        # parse them even though they are not marked for translation.
        # Extracting with an explicit encoding of ISO-8859-1 will make
        # xgettext "parse" and ignore them.
	echo $(PYFILES) | xargs \
	  xgettext --package-name "Mercurial" \
	  --msgid-bugs-address "<[e-mail]>" \
	  --copyright-holder "Matt Mackall <[e-mail]> and others" \
	  --from-code ISO-8859-1 --join --sort-by-file --add-comments=i18n: \
	  -d hg -p i18n -o hg.pot.tmp
	$(PYTHON) i18n/posplit i18n/hg.pot.tmp
        # The target file is not created before the last step. So it never is in
        # an intermediate state.
	mv -f i18n/hg.pot.tmp i18n/hg.pot

%.po: i18n/hg.pot
        # work on a temporary copy for never having a half completed target
	cp $@ $@.tmp
	msgmerge --no-location --update $@.tmp $^
	mv -f $@.tmp $@

# Packaging targets

osx:
	python -c 'import bdist_mpkg.script_bdist_mpkg' || \
	   (echo "Missing bdist_mpkg (easy_install bdist_mpkg)"; false)
	rm -rf dist/mercurial-*.mpkg
	python -m bdist_mpkg.script_bdist_mpkg setup.py --
	python contrib/fixpax.py dist/mercurial-*.mpkg/Contents/Packages/*.pkg/Contents/Archive.pax.gz
	mkdir -p packages/osx
	N=`cd dist && echo mercurial-*.mpkg | sed 's,\.mpkg$$,,'` && hdiutil create -srcfolder dist/$$N.mpkg/ -scrub -volname "$$N" -ov packages/osx/$$N.dmg
	rm -rf dist/mercurial-*.mpkg

deb:
	contrib/builddeb

docker-debian-jessie:
	mkdir -p packages/debian-jessie
	contrib/dockerdeb debian jessie

fedora20:
	mkdir -p packages/fedora20
	contrib/buildrpm
	cp rpmbuild/RPMS/*/* packages/fedora20
	cp rpmbuild/SRPMS/* packages/fedora20
	rm -rf rpmbuild

docker-fedora20:
	mkdir -p packages/fedora20
	contrib/dockerrpm fedora20

fedora21:
	mkdir -p packages/fedora21
	contrib/buildrpm
	cp rpmbuild/RPMS/*/* packages/fedora21
	cp rpmbuild/SRPMS/* packages/fedora21
	rm -rf rpmbuild

docker-fedora21:
	mkdir -p packages/fedora21
	contrib/dockerrpm fedora21

centos5:
	mkdir -p packages/centos5
	contrib/buildrpm --withpython
	cp rpmbuild/RPMS/*/* packages/centos5
	cp rpmbuild/SRPMS/* packages/centos5

docker-centos5:
	mkdir -p packages/centos5
	contrib/dockerrpm centos5 --withpython

centos6:
	mkdir -p packages/centos6
	contrib/buildrpm
	cp rpmbuild/RPMS/*/* packages/centos6
	cp rpmbuild/SRPMS/* packages/centos6

docker-centos6:
	mkdir -p packages/centos6
	contrib/dockerrpm centos6

centos7:
	mkdir -p packages/centos7
	contrib/buildrpm
	cp rpmbuild/RPMS/*/* packages/centos7
	cp rpmbuild/SRPMS/* packages/centos7

docker-centos7:
	mkdir -p packages/centos7
	contrib/dockerrpm centos7

.PHONY: help all local build doc clean install install-bin install-doc \
	install-home install-home-bin install-home-doc \
	dist dist-notests check tests check-code update-pot \
	osx fedora20 docker-fedora20 fedora21 docker-fedora21 \
	centos5 docker-centos5 centos6 docker-centos6 centos7 docker-centos7