From nobody Sun Feb 8 14:57:16 2026 Received: from mail-lf1-f43.google.com (mail-lf1-f43.google.com [209.85.167.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A35B194A63 for ; Mon, 18 Nov 2024 11:01:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.43 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731927716; cv=none; b=gosM+ORt8kVoEKXDmiIlhLifo+NNkzoR0h5sI5kgDM3isUxOFrnruSeQH4o+44i1WoEC7AlacBVK269+p5n/B6xSy2OFHbNcsX5Vn4nNi5MdZkU+FmmAY//qfQlcqiNmPtMG22JJWokbLqPzyNJ6AS2j7SB1Ltgrwvw2rkUXirk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731927716; c=relaxed/simple; bh=/mmqxQIIBTKJU95znxubYAuwPz0Pj4FHpPgJoJZHwCY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jAudbNHm+qAbAyo01eWAe7GUduT1U7pjTNp305pF8OiHIm4p/N/MeceQxCO6kifYfEPJr4TRh2tOxQYxaYIAIiYfFcZAJcymVYrqm+H+3QENCLBv0i3D7yncwl7XBLfe+4Bz02UDSkBsIybETrWlocboExXDcDesPY8zO9/0wqk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rasmusvillemoes.dk; spf=pass smtp.mailfrom=rasmusvillemoes.dk; dkim=pass (1024-bit key) header.d=rasmusvillemoes.dk header.i=@rasmusvillemoes.dk header.b=EJ4wYrli; arc=none smtp.client-ip=209.85.167.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rasmusvillemoes.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rasmusvillemoes.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=rasmusvillemoes.dk header.i=@rasmusvillemoes.dk header.b="EJ4wYrli" Received: by mail-lf1-f43.google.com with SMTP id 2adb3069b0e04-539f84907caso4331164e87.3 for ; Mon, 18 Nov 2024 03:01:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; t=1731927712; x=1732532512; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=VabMAuGwTL06yr3ViS1JrPQ2en669i6+uOZedAFhYnI=; b=EJ4wYrliARRMA9vf5VRfq+mQ7mJfO7dPii/EvPtdP5V1Jojq/jfrHuSZE/p8qOCh22 wu4erEmeP+vDvwk5+qB+6CtFeB9fSO5WTg0P9qG3UyviITqjpBqOldF2qujkX7AdiwoL OsKqczgD9stEXmEKcbyP1J13pn7ePgAWdIabs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731927712; x=1732532512; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=VabMAuGwTL06yr3ViS1JrPQ2en669i6+uOZedAFhYnI=; b=v1sCd27gQD2olLdpR5gzrPCTCZ499Xgoajbhf7zbxyRFVvdUjLhWLV/i7UQzjBMtNl woSfZjC6/MW1B8UhgzSFA7c7jiGgIj794EnmZpREGydLanMJBqJAyiwgMCQOPxpAEAK+ H29qAKaq4SD6QvCi+hS8mvsZSn0HgwAl6UFcPo4gyf+Eb9qISH2SCdbhdb3z4iZokqNy NbL+hnaCJSE+AJZTFco3EQFIttPvhw7UIMSKJv0mMhJSv8qPAHPq0PXuSRmbaqLtAJII 5Z1pnPTEp5pLkT7jukLO/Lzv/kj9qSJ/GP1vwuXFyZGILd+wiXw4REYt3RL+qeqQ40Tm pRFg== X-Gm-Message-State: AOJu0YxeRd0/xx3xDVXwMRwZUWRP3cQjl4RTw7vlpoDoqq6ax0RNsvTT fs5Ri4BtxgSzaPWk18+cWcCkPOT8Qna5ieGDdVNIs7VOzOEeYzbKkD1QXwopy2PqZPUWEKwsmVq pw00= X-Google-Smtp-Source: AGHT+IHGEQGWW6igmzapud9eLSNtzJT0ArhpXDj23UyLyIJqeURWIy0rpxNdqZ1XisNIQLlwCcH+vg== X-Received: by 2002:a2e:bc05:0:b0:2fa:dadf:aad5 with SMTP id 38308e7fff4ca-2ff609b4c03mr60813561fa.28.1731927711949; Mon, 18 Nov 2024 03:01:51 -0800 (PST) Received: from localhost ([81.216.59.226]) by smtp.gmail.com with ESMTPSA id 38308e7fff4ca-2ff69ae80fesm9176091fa.89.2024.11.18.03.01.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Nov 2024 03:01:51 -0800 (PST) From: Rasmus Villemoes To: Masahiro Yamada , linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jeff King , Rasmus Villemoes , Sean Christopherson , Josh Poimboeuf Subject: [PATCH v3] setlocalversion: work around "git describe" performance Date: Mon, 18 Nov 2024 12:01:54 +0100 Message-ID: <20241118110154.3711777-1-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Contrary to expectations, passing a single candidate tag to "git describe" is slower than not passing any --match options. $ time git describe --debug ... traversed 10619 commits ... v6.12-rc5-63-g0fc810ae3ae1 real 0m0.169s $ time git describe --match=3Dv6.12-rc5 --debug ... traversed 1310024 commits v6.12-rc5-63-g0fc810ae3ae1 real 0m1.281s In fact, the --debug output shows that git traverses all or most of history. For some repositories and/or git versions, those 1.3s are actually 10-15 seconds. This has been acknowledged as a performance bug in git [1], and a fix is on its way [2]. However, no solution is yet in git.git, and even when one lands, it will take quite a while before it finds its way to a release and for $random_kernel_developer to pick that up. So rewrite the logic to use plumbing commands. For each of the candidate values of $tag, we ask: (1) is $tag even an annotated tag? (2) Is it eligible to describe HEAD, i.e. an ancestor of HEAD? (3) If so, how many commits are in $tag..HEAD? I have tested that this produces the same output as the current script for ~700 random commits between v6.9..v6.10. For those 700 commits, and in my git repo, the 'make -s kernelrelease' command is on average ~4 times faster with this patch applied (geometric mean of ratios). For the commit mentioned in Josh's original report [3], the time-consuming part of setlocalversion goes from $ time git describe --match=3Dv6.12-rc5 c1e939a21eb1 v6.12-rc5-44-gc1e939a21eb1 real 0m1.210s to $ time git rev-list --count --left-right v6.12-rc5..c1e939a21eb1 0 44 real 0m0.037s [1] https://lore.kernel.org/git/20241101113910.GA2301440@coredump.intra.pef= f.net/ [2] https://lore.kernel.org/git/20241106192236.GC880133@coredump.intra.peff= .net/ [3] https://lore.kernel.org/lkml/309549cafdcfe50c4fceac3263220cc3d8b109b2.1= 730337435.git.jpoimboe@kernel.org/ Reported-by: Sean Christopherson Closes: https://lore.kernel.org/lkml/ZPtlxmdIJXOe0sEy@google.com/ Reported-by: Josh Poimboeuf Tested-by: Josh Poimboeuf Closes: https://lore.kernel.org/lkml/309549cafdcfe50c4fceac3263220cc3d8b109= b2.1730337435.git.jpoimboe@kernel.org/ Signed-off-by: Rasmus Villemoes --- v3: - Update trailer tag list, per Masahiro. - Drop redundant quoutes around the word tag - Add a shellcheck disable directive Masahiro, I decided to keep the changes minimal, in particular not to change anything around the logic or the (unused) return values, in order not to invalidate Josh' T-b tag. I think it's more important for this to make it to 6.13-rc1 (if that is even still possible, given that the MW is already open). Since you mentioned shellcheck, which I myself am a big fan of, I added a directive in the new code, but didn't want to try to make the whole script shellcheck clean. But I don't know if we want such linter directives; if not, feel free to just remove that line. v2: https://lore.kernel.org/lkml/20241112210500.2266762-1-linux@rasmusville= moes.dk/ scripts/setlocalversion | 54 +++++++++++++++++++++++++++++------------ 1 file changed, 38 insertions(+), 16 deletions(-) diff --git a/scripts/setlocalversion b/scripts/setlocalversion index 38b96c6797f4..5818465abba9 100755 --- a/scripts/setlocalversion +++ b/scripts/setlocalversion @@ -30,6 +30,27 @@ if test $# -gt 0 -o ! -d "$srctree"; then usage fi =20 +try_tag() { + tag=3D"$1" + + # Is $tag an annotated tag? + [ "$(git cat-file -t "$tag" 2> /dev/null)" =3D tag ] || return 1 + + # Is it an ancestor of HEAD, and if so, how many commits are in $tag..HEA= D? + # shellcheck disable=3DSC2046 # word splitting is the point here + set -- $(git rev-list --count --left-right "$tag"...HEAD 2> /dev/null) + + # $1 is 0 if and only if $tag is an ancestor of HEAD. Use + # string comparison, because $1 is empty if the 'git rev-list' + # command somehow failed. + [ "$1" =3D 0 ] || return 1 + + # $2 is the number of commits in the range $tag..HEAD, possibly 0. + count=3D"$2" + + return 0 +} + scm_version() { local short=3Dfalse @@ -61,33 +82,33 @@ scm_version() # stable kernel: 6.1.7 -> v6.1.7 version_tag=3Dv$(echo "${KERNELVERSION}" | sed -E 's/^([0-9]+\.[0-9]+)\.0= (.*)$/\1\2/') =20 + # try_tag initializes count if the tag is usable. + count=3D + # If a localversion* file exists, and the corresponding # annotated tag exists and is an ancestor of HEAD, use # it. This is the case in linux-next. - tag=3D${file_localversion#-} - desc=3D - if [ -n "${tag}" ]; then - desc=3D$(git describe --match=3D$tag 2>/dev/null) + if [ -n "${file_localversion#-}" ] ; then + try_tag "${file_localversion#-}" fi =20 # Otherwise, if a localversion* file exists, and the tag # obtained by appending it to the tag derived from # KERNELVERSION exists and is an ancestor of HEAD, use # it. This is e.g. the case in linux-rt. - if [ -z "${desc}" ] && [ -n "${file_localversion}" ]; then - tag=3D"${version_tag}${file_localversion}" - desc=3D$(git describe --match=3D$tag 2>/dev/null) + if [ -z "${count}" ] && [ -n "${file_localversion}" ]; then + try_tag "${version_tag}${file_localversion}" fi =20 # Otherwise, default to the annotated tag derived from KERNELVERSION. - if [ -z "${desc}" ]; then - tag=3D"${version_tag}" - desc=3D$(git describe --match=3D$tag 2>/dev/null) + if [ -z "${count}" ]; then + try_tag "${version_tag}" fi =20 - # If we are at the tagged commit, we ignore it because the version is - # well-defined. - if [ "${tag}" !=3D "${desc}" ]; then + # If we are at the tagged commit, we ignore it because the + # version is well-defined. If none of the attempted tags exist + # or were usable, $count is still empty. + if [ -z "${count}" ] || [ "${count}" -gt 0 ]; then =20 # If only the short version is requested, don't bother # running further git commands @@ -95,14 +116,15 @@ scm_version() echo "+" return fi + # If we are past the tagged commit, we pretty print it. # (like 6.1.0-14595-g292a089d78d3) - if [ -n "${desc}" ]; then - echo "${desc}" | awk -F- '{printf("-%05d", $(NF-1))}' + if [ -n "${count}" ]; then + printf "%s%05d" "-" "${count}" fi =20 # Add -g and exactly 12 hex chars. - printf '%s%s' -g "$(echo $head | cut -c1-12)" + printf '%s%.12s' -g "$head" fi =20 if ${no_dirty}; then --=20 2.47.0