##// END OF EJS Templates
util: implement zstd compression engine...
util: implement zstd compression engine Now that zstd is vendored and being built (in some configurations), we can implement a compression engine for zstd! The zstd engine is a little different from existing engines. Because it may not always be present, we have to defer load the module in case importing it fails. We facilitate this via a cached property that holds a reference to the module or None. The "available" method is implemented to reflect reality. The zstd engine declares its ability to handle bundles using the "zstd" human name and the "ZS" internal name. The latter was chosen because internal names are 2 characters (by only convention I think) and "ZS" seems reasonable. The engine, like others, supports specifying the compression level. However, there are no consumers of this API that yet pass in that argument. I have plans to change that, so stay tuned. Since all we need to do to support bundle generation with a new compression engine is implement and register the compression engine, bundle generation with zstd "just works!" Tests demonstrating this have been added. How does performance of zstd for bundle generation compare? On the mozilla-unified repo, `hg bundle --all -t <engine>-v2` yields the following on my i7-6700K on Linux: engine CPU time bundle size vs orig size throughput none 97.0s 4,054,405,584 100.0% 41.8 MB/s bzip2 (l=9) 393.6s 975,343,098 24.0% 10.3 MB/s gzip (l=6) 184.0s 1,140,533,074 28.1% 22.0 MB/s zstd (l=1) 108.2s 1,119,434,718 27.6% 37.5 MB/s zstd (l=2) 111.3s 1,078,328,002 26.6% 36.4 MB/s zstd (l=3) 113.7s 1,011,823,727 25.0% 35.7 MB/s zstd (l=4) 116.0s 1,008,965,888 24.9% 35.0 MB/s zstd (l=5) 121.0s 977,203,148 24.1% 33.5 MB/s zstd (l=6) 131.7s 927,360,198 22.9% 30.8 MB/s zstd (l=7) 139.0s 912,808,505 22.5% 29.2 MB/s zstd (l=12) 198.1s 854,527,714 21.1% 20.5 MB/s zstd (l=18) 681.6s 789,750,690 19.5% 5.9 MB/s On compression, zstd for bundle generation delivers: * better compression than gzip with significantly less CPU utilization * better than bzip2 compression ratios while still being significantly faster than gzip * ability to aggressively tune compression level to achieve significantly smaller bundles That last point is important. With clone bundles, a server can pre-generate a bundle file, upload it to a static file server, and redirect clients to transparently download it during clone. The server could choose to produce a zstd bundle with the highest compression settings possible. This would take a very long time - a magnitude longer than a typical zstd bundle generation - but the result would be hundreds of megabytes smaller! For the clone volume we do at Mozilla, this could translate to petabytes of bandwidth savings per year and faster clones (due to smaller transfer size). I don't have detailed numbers to report on decompression. However, zstd decompression is fast: >1 GB/s output throughput on this machine, even through the Python bindings. And it can do that regardless of the compression level of the input. By the time you have enough data to worry about overhead of decompression, you have plenty of other things to worry about performance wise. zstd is wins all around. I can't wait to implement support for it on the wire protocol and in revlogs.

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buildrpm
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#!/bin/bash -e
#
# Build a Mercurial RPM from the current repo
#
# Tested on
# - Fedora 20
# - CentOS 5
# - centOS 6
. $(dirname $0)/packagelib.sh
BUILD=1
RPMBUILDDIR="$PWD/rpmbuild"
while [ "$1" ]; do
case "$1" in
--prepare )
shift
BUILD=
;;
--withpython | --with-python)
shift
PYTHONVER=2.7.10
PYTHONMD5=d7547558fd673bd9d38e2108c6b42521
;;
--rpmbuilddir )
shift
RPMBUILDDIR="$1"
shift
;;
* )
echo "Invalid parameter $1!" 1>&2
exit 1
;;
esac
done
cd "`dirname $0`/.."
specfile=$PWD/contrib/mercurial.spec
if [ ! -f $specfile ]; then
echo "Cannot find $specfile!" 1>&2
exit 1
fi
if [ ! -d .hg ]; then
echo 'You are not inside a Mercurial repository!' 1>&2
exit 1
fi
gethgversion
# TODO: handle distance/node set, and type set
if [ -z "$type" ] ; then
release=1
else
release=0.9_$type
fi
if [ -n "$distance" ] ; then
release=$release+$distance_$node
fi
if [ "$PYTHONVER" ]; then
release=$release+$PYTHONVER
RPMPYTHONVER=$PYTHONVER
else
RPMPYTHONVER=%{nil}
fi
mkdir -p $RPMBUILDDIR/{SOURCES,BUILD,SRPMS,RPMS}
$HG archive -t tgz $RPMBUILDDIR/SOURCES/mercurial-$version-$release.tar.gz
if [ "$PYTHONVER" ]; then
(
mkdir -p build
cd build
PYTHON_SRCFILE=Python-$PYTHONVER.tgz
[ -f $PYTHON_SRCFILE ] || curl -Lo $PYTHON_SRCFILE http://www.python.org/ftp/python/$PYTHONVER/$PYTHON_SRCFILE
if [ "$PYTHONMD5" ]; then
echo "$PYTHONMD5 $PYTHON_SRCFILE" | md5sum -w -c
fi
ln -f $PYTHON_SRCFILE $RPMBUILDDIR/SOURCES/$PYTHON_SRCFILE
DOCUTILSVER=`sed -ne "s/^%global docutilsname docutils-//p" $specfile`
DOCUTILS_SRCFILE=docutils-$DOCUTILSVER.tar.gz
[ -f $DOCUTILS_SRCFILE ] || curl -Lo $DOCUTILS_SRCFILE http://downloads.sourceforge.net/project/docutils/docutils/$DOCUTILSVER/$DOCUTILS_SRCFILE
DOCUTILSMD5=`sed -ne "s/^%global docutilsmd5 //p" $specfile`
if [ "$DOCUTILSMD5" ]; then
echo "$DOCUTILSMD5 $DOCUTILS_SRCFILE" | md5sum -w -c
fi
ln -f $DOCUTILS_SRCFILE $RPMBUILDDIR/SOURCES/$DOCUTILS_SRCFILE
)
fi
mkdir -p $RPMBUILDDIR/SPECS
rpmspec=$RPMBUILDDIR/SPECS/mercurial.spec
sed -e "s,^Version:.*,Version: $version," \
-e "s,^Release:.*,Release: $release," \
$specfile > $rpmspec
echo >> $rpmspec
echo "%changelog" >> $rpmspec
if echo $version | grep '+' > /dev/null 2>&1; then
latesttag="`echo $version | sed -e 's/+.*//'`"
$HG log -r .:"$latesttag" -fM \
--template '{date|hgdate}\t{author}\t{desc|firstline}\n' | python -c '
import sys, time
def datestr(date, format):
return time.strftime(format, time.gmtime(float(date[0]) - date[1]))
changelog = []
for l in sys.stdin.readlines():
tok = l.split("\t")
hgdate = tuple(int(v) for v in tok[0].split())
changelog.append((datestr(hgdate, "%F"), tok[1], hgdate, tok[2]))
prevtitle = ""
for l in sorted(changelog, reverse=True):
title = "* %s %s" % (datestr(l[2], "%a %b %d %Y"), l[1])
if prevtitle != title:
prevtitle = title
print
print title
print "- %s" % l[3].strip()
' >> $rpmspec
else
$HG log \
--template '{date|hgdate}\t{author}\t{desc|firstline}\n' \
.hgtags | python -c '
import sys, time
def datestr(date, format):
return time.strftime(format, time.gmtime(float(date[0]) - date[1]))
for l in sys.stdin.readlines():
tok = l.split("\t")
hgdate = tuple(int(v) for v in tok[0].split())
print "* %s %s\n- %s" % (datestr(hgdate, "%a %b %d %Y"), tok[1], tok[2])
' >> $rpmspec
fi
sed -i \
-e "s/^%define withpython.*$/%define withpython $RPMPYTHONVER/" \
$rpmspec
if [ "$BUILD" ]; then
rpmbuild --define "_topdir $RPMBUILDDIR" -ba $rpmspec --clean
if [ $? = 0 ]; then
echo
echo "Built packages for $version-$release:"
find $RPMBUILDDIR/*RPMS/ -type f -newer $rpmspec
fi
else
echo "Prepared sources for $version-$release $rpmspec are in $RPMBUILDDIR/SOURCES/ - use like:"
echo "rpmbuild --define '_topdir $RPMBUILDDIR' -ba $rpmspec --clean"
fi