From: Thomas Rast <trast@student.ethz.ch>
Date: Tue, 6 Mar 2012 13:15:01 +0000 (+0100)
Subject: perf: compare diff algorithms
X-Git-Tag: v1.7.10-rc0~11
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=85551232b56e763ecfcc7222e0858bac4e962c80;p=git.git

perf: compare diff algorithms

8c912ee (teach --histogram to diff, 2011-07-12) claimed histogram diff
was faster than both Myers and patience.

We have since incorporated a performance testing framework, so add a
test that compares the various diff tasks performed in a real 'log -p'
workload.  This does indeed show that histogram diff slightly beats
Myers, while patience is much slower than the others.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/t/perf/p4000-diff-algorithms.sh b/t/perf/p4000-diff-algorithms.sh
new file mode 100755
index 000000000..d6e505c78
--- /dev/null
+++ b/t/perf/p4000-diff-algorithms.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+
+test_description="Tests diff generation performance"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_perf 'log -3000 (baseline)' '
+	git log -1000 >/dev/null
+'
+
+test_perf 'log --raw -3000 (tree-only)' '
+	git log --raw -3000 >/dev/null
+'
+
+test_perf 'log -p -3000 (Myers)' '
+	git log -p -3000 >/dev/null
+'
+
+test_perf 'log -p -3000 --histogram' '
+	git log -p -3000 --histogram >/dev/null
+'
+
+test_perf 'log -p -3000 --patience' '
+	git log -p -3000 --patience >/dev/null
+'
+
+test_done