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Message-ID: <309549cafdcfe50c4fceac3263220cc3d8b109b2.1730337435.git.jpoimboe@kernel.org>
Date: Wed, 30 Oct 2024 18:20:21 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: Masahiro Yamada <masahiroy@...nel.org>
Cc: linux-kernel@...r.kernel.org,
linux-kbuild@...r.kernel.org
Subject: [PATCH] setlocalversion: Add workaround for "git describe" performance issue
If HEAD isn't associated with an annotated tag, a bug (or feature?) in
"git describe --match" causes it to search every commit in the entire
repository looking for additional match candidates. Instead of it
taking a fraction of a second, it adds 10-15 seconds to the beginning of
every kernel build.
Fix it by adding an additional dummy match which is slightly further
away from the most recent one, along with setting the max candidate
count to 1 (not 2, apparently another bug).
Before:
$ git checkout c1e939a21eb1
$ time make kernel/fork.o -s
real 0m12.403s
user 0m11.591s
sys 0m0.967s
After:
$ time make kernel/fork.o -s
real 0m1.119s
user 0m0.658s
sys 0m0.659s
Link: https://lore.kernel.org/git/20241030044322.b5n3ji2n6gaeo5u6@treble.attlocal.net/
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
scripts/setlocalversion | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/scripts/setlocalversion b/scripts/setlocalversion
index 38b96c6797f4..bb8c0bcb7368 100755
--- a/scripts/setlocalversion
+++ b/scripts/setlocalversion
@@ -57,6 +57,8 @@ scm_version()
return
fi
+ githack=" --match=v6.11 --candidates=1"
+
# mainline kernel: 6.2.0-rc5 -> v6.2-rc5
# stable kernel: 6.1.7 -> v6.1.7
version_tag=v$(echo "${KERNELVERSION}" | sed -E 's/^([0-9]+\.[0-9]+)\.0(.*)$/\1\2/')
@@ -67,7 +69,7 @@ scm_version()
tag=${file_localversion#-}
desc=
if [ -n "${tag}" ]; then
- desc=$(git describe --match=$tag 2>/dev/null)
+ desc=$(git describe --match=$tag $githack 2>/dev/null)
fi
# Otherwise, if a localversion* file exists, and the tag
@@ -76,13 +78,13 @@ scm_version()
# it. This is e.g. the case in linux-rt.
if [ -z "${desc}" ] && [ -n "${file_localversion}" ]; then
tag="${version_tag}${file_localversion}"
- desc=$(git describe --match=$tag 2>/dev/null)
+ desc=$(git describe --match=$tag $githack 2>/dev/null)
fi
# Otherwise, default to the annotated tag derived from KERNELVERSION.
if [ -z "${desc}" ]; then
tag="${version_tag}"
- desc=$(git describe --match=$tag 2>/dev/null)
+ desc=$(git describe --match=$tag $githack 2>/dev/null)
fi
# If we are at the tagged commit, we ignore it because the version is
--
2.47.0
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