The new bisect_regression script can be used to automatically bisect
performance regressions. It will pass the new bisect_run_script to
`git bisect run`.
Signed-off-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
---
t/perf/bisect_regression | 73 ++++++++++++++++++++++++++++++++++++++++
t/perf/bisect_run_script | 47 ++++++++++++++++++++++++++
2 files changed, 120 insertions(+)
create mode 100755 t/perf/bisect_regression
create mode 100755 t/perf/bisect_run_script
diff --git a/t/perf/bisect_regression b/t/perf/bisect_regression
new file mode 100755
index 0000000000..a94d9955d0
--- /dev/null
+++ b/t/perf/bisect_regression
@@ -0,0 +1,73 @@
+#!/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' shoud 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"
+)
diff --git a/t/perf/bisect_run_script b/t/perf/bisect_run_script
new file mode 100755
index 0000000000..038255df4b
--- /dev/null
+++ b/t/perf/bisect_run_script
@@ -0,0 +1,47 @@
+#!/bin/sh
+
+script="$1"
+test_number="$2"
+info_dir="$3"
+
+# This aborts the bisection immediately
+die () {
+ echo >&2 "error: $*"
+ exit 255
+}
+
+bisect_head=$(git rev-parse --verify BISECT_HEAD) || die "Failed to find BISECT_HEAD ref"
+
+script_number=$(echo "$script" | sed -e "s/^p\([0-9]*\).*\$/\1/") || die "Failed to get script number for '$script'"
+
+oldtime=$(cat "$info_dir/oldtime") || die "Failed to access '$info_dir/oldtime'"
+newtime=$(cat "$info_dir/newtime") || die "Failed to access '$info_dir/newtime'"
+
+cd t/perf || die "Failed to cd into 't/perf'"
+
+result_file="$info_dir/perf_${script_number}_${bisect_head}_results.txt"
+
+GIT_PERF_DIRS_OR_REVS="$bisect_head"
+export GIT_PERF_DIRS_OR_REVS
+
+./run "$script" >"$result_file" 2>&1 || die "Failed to run perf test '$script'"
+
+rtime=$(sed -n "s/^$script_number\.$test_number:.*\([0-9]\+\.[0-9]\+\)(.*).*\$/\1/p" "$result_file")
+
+echo "newtime: $newtime"
+echo "rtime: $rtime"
+echo "oldtime: $oldtime"
+
+# Compare ($newtime - $rtime) with ($rtime - $oldtime)
+# Times are decimal number, not integers
+
+if test $(echo "$newtime" "$rtime" "$oldtime" | awk '{ print ($1 - $2 > $2 - $3) }') = 1
+then
+ # Current commit is considered "good/old"
+ echo "$rtime" >"$info_dir/oldtime"
+ exit 0
+else
+ # Current commit is considered "bad/new"
+ echo "$rtime" >"$info_dir/newtime"
+ exit 1
+fi
--
2.17.0.rc1.36.g098d832c9.dirty
