tvl-depot/third_party/git/t/perf/bisect_regression
Vincent Ambo f4609b896f merge(3p/git): Merge git subtree at v2.29.2
This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb
2020-11-21 19:45:56 +01:00

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#!/bin/sh
# Read a line coming from `./aggregate.perl --sort-by regression ...`
# and automatically bisect to find the commit responsible for the
# performance regression.
#
# Lines from `./aggregate.perl --sort-by regression ...` look like:
#
# +100.0% p7821-grep-engines-fixed.1 0.04(0.10+0.03) 0.08(0.11+0.08) v2.14.3 v2.15.1
# +33.3% p7820-grep-engines.1 0.03(0.08+0.02) 0.04(0.08+0.02) v2.14.3 v2.15.1
#
die () {
echo >&2 "error: $*"
exit 1
}
while [ $# -gt 0 ]; do
arg="$1"
case "$arg" in
--help)
echo "usage: $0 [--config file] [--subsection subsection]"
exit 0
;;
--config)
shift
GIT_PERF_CONFIG_FILE=$(cd "$(dirname "$1")"; pwd)/$(basename "$1")
export GIT_PERF_CONFIG_FILE
shift ;;
--subsection)
shift
GIT_PERF_SUBSECTION="$1"
export GIT_PERF_SUBSECTION
shift ;;
--*)
die "unrecognised option: '$arg'" ;;
*)
die "unknown argument '$arg'"
;;
esac
done
read -r regression subtest oldtime newtime oldrev newrev
test_script=$(echo "$subtest" | sed -e 's/\(.*\)\.[0-9]*$/\1.sh/')
test_number=$(echo "$subtest" | sed -e 's/.*\.\([0-9]*\)$/\1/')
# oldtime and newtime are decimal number, not integers
oldtime=$(echo "$oldtime" | sed -e 's/^\([0-9]\+\.[0-9]\+\).*$/\1/')
newtime=$(echo "$newtime" | sed -e 's/^\([0-9]\+\.[0-9]\+\).*$/\1/')
test $(echo "$newtime" "$oldtime" | awk '{ print ($1 > $2) }') = 1 ||
die "New time '$newtime' should be greater than old time '$oldtime'"
tmpdir=$(mktemp -d -t bisect_regression_XXXXXX) || die "Failed to create temp directory"
echo "$oldtime" >"$tmpdir/oldtime" || die "Failed to write to '$tmpdir/oldtime'"
echo "$newtime" >"$tmpdir/newtime" || die "Failed to write to '$tmpdir/newtime'"
# Bisecting must be performed from the top level directory (even with --no-checkout)
(
toplevel_dir=$(git rev-parse --show-toplevel) || die "Failed to find top level directory"
cd "$toplevel_dir" || die "Failed to cd into top level directory '$toplevel_dir'"
git bisect start --no-checkout "$newrev" "$oldrev" || die "Failed to start bisecting"
git bisect run t/perf/bisect_run_script "$test_script" "$test_number" "$tmpdir"
res="$?"
git bisect reset
exit "$res"
)