bdiff: don't check border condition in loop
This is pretty much a copy of d500ddae7494, just to a different loop.
The condition `p == plast` (`plast == a + len - 1`) was only true on
the final iteration of the loop. So it was wasteful to check for it
on every iteration. We decrease the iteration count by 1 and add an
explicit check for `p == plast` after the loop.
Again, we see modest wins.
From the mozilla-unified repository:
$ perfbdiff -m 3041e4d59df2
! wall 0.035502 comb 0.040000 user 0.040000 sys 0.000000 (best of 100)
! wall 0.030480 comb 0.030000 user 0.030000 sys 0.000000 (best of 100)
$ perfbdiff 0e9928989e9c --alldata --count 100
! wall 4.097394 comb 4.100000 user 4.100000 sys 0.000000 (best of 3)
! wall 3.597798 comb 3.600000 user 3.600000 sys 0.000000 (best of 3)
The 2nd example throws a total of ~3.3GB of data at bdiff. This
change increases the throughput from ~811 MB/s to ~924 MB/s.
#!/bin/bash
# This script gets executed on container start. Its job is to set up
# the Mercurial environment and invoke the server.
# Mercurial can be started in two modes.
# If the MERCURIAL_SOURCE environment variable is set and it points to a
# Mercurial source directory, we will install Mercurial from that directory.
# Otherwise, we download the Mercurial source and install it manually.
set -e
SOURCE_DIR=/var/hg/source
INSTALL_DIR=/var/hg/install
REPOS_DIR=/var/hg/repos
HTDOCS_DIR=/var/hg/htdocs
if [ ! -d ${SOURCE_DIR} ]; then
echo "Mercurial source not available at ${SOURCE_DIR}"
echo "You need to mount a volume containing the Mercurial source code"
echo "when running the container. For example:"
echo ""
echo " $ docker run -v ~/src/hg:/${SOURCE_DIR} hg-apache"
echo ""
echo "This container will now stop running."
exit 1
fi
echo "Installing Mercurial from ${SOURCE_DIR} into ${INSTALL_DIR}"
pushd ${SOURCE_DIR}
/usr/bin/python2.7 setup.py install --root=/ --prefix=${INSTALL_DIR} --force
popd
mkdir -p ${HTDOCS_DIR}
# Provide a default config if the user hasn't supplied one.
if [ ! -f ${HTDOCS_DIR}/config ]; then
cp /defaulthgwebconfig ${HTDOCS_DIR}/config
fi
if [ ! -f ${HTDOCS_DIR}/hgweb.wsgi ]; then
cat >> ${HTDOCS_DIR}/hgweb.wsgi << EOF
config = '${HTDOCS_DIR}/config'
import sys
sys.path.insert(0, '${INSTALL_DIR}/lib/python2.7/site-packages')
from mercurial import demandimport
demandimport.enable()
from mercurial.hgweb import hgweb
application = hgweb(config)
EOF
fi
mkdir -p ${REPOS_DIR}
if [ ! -d ${REPOS_DIR}/repo ]; then
${INSTALL_DIR}/bin/hg init ${REPOS_DIR}/repo
chown -R www-data:www-data ${REPOS_DIR}/repo
fi
# This is necessary to make debuginstall happy.
if [ ! -f ~/.hgrc ]; then
cat >> ~/.hgrc << EOF
[ui]
username = Dummy User <nobody@example.com>
EOF
fi
echo "Verifying Mercurial installation looks happy"
${INSTALL_DIR}/bin/hg debuginstall
. /etc/apache2/envvars
echo "Starting Apache HTTP Server on port 80"
echo "We hope you remembered to publish this port when running the container!"
echo "If this is an interactive container, simply CTRL^C to stop."
exec "$@"