From b95b0928ac7135322dd3d42c19d489ede35bf121 Mon Sep 17 00:00:00 2001 From: John Crispin Date: Sun, 20 Sep 2026 15:52:08 +0200 Subject: [PATCH] build: add per stage build time profiling Set BUILD_TIME_LOG= to record a begin and an end event for every prepare, configure, compile and install stage of every tool, toolchain component, kernel and package. scripts/build-time-report.pl turns the log into a report. The report divides each second of the build between the stages that run in it, so the numbers show which stages hold up the wall clock rather than which ones burn the most CPU. Nothing is recorded and no extra process runs when BUILD_TIME_LOG is unset. Signed-off-by: John Crispin --- include/host-build.mk | 8 ++ include/kernel-build.mk | 10 ++ include/package.mk | 8 ++ rules.mk | 10 ++ scripts/build-time-log.sh | 18 ++++ scripts/build-time-report.pl | 181 +++++++++++++++++++++++++++++++++++ 6 files changed, 235 insertions(+) create mode 100755 scripts/build-time-log.sh create mode 100755 scripts/build-time-report.pl diff --git a/include/host-build.mk b/include/host-build.mk index 9673d5c03c9..b459c0ab18c 100644 --- a/include/host-build.mk +++ b/include/host-build.mk @@ -182,34 +182,42 @@ ifndef DUMP $(if $(DUMP),,$(call HostHost/Autoclean)) $(HOST_STAMP_PREPARED): + $(call BuildTimeLog,begin,prepare) @-rm -rf $(HOST_BUILD_DIR) @mkdir -p $(HOST_BUILD_DIR) $(foreach hook,$(Hooks/HostPrepare/Pre),$(call $(hook))$(sep)) $(call Host/Prepare) $(foreach hook,$(Hooks/HostPrepare/Post),$(call $(hook))$(sep)) touch $$@ + $(call BuildTimeLog,end,prepare) $(call Host/Exports,$(HOST_STAMP_CONFIGURED)) $(HOST_STAMP_CONFIGURED): $(HOST_STAMP_PREPARED) + $(call BuildTimeLog,begin,configure) $(foreach hook,$(Hooks/HostConfigure/Pre),$(call $(hook))$(sep)) $(call Host/Configure) $(foreach hook,$(Hooks/HostConfigure/Post),$(call $(hook))$(sep)) touch $$@ + $(call BuildTimeLog,end,configure) $(call Host/Exports,$(HOST_STAMP_BUILT)) $(HOST_STAMP_BUILT): $(HOST_STAMP_CONFIGURED) + $(call BuildTimeLog,begin,compile) $(foreach hook,$(Hooks/HostCompile/Pre),$(call $(hook))$(sep)) $(call Host/Compile) $(foreach hook,$(Hooks/HostCompile/Post),$(call $(hook))$(sep)) touch $$@ + $(call BuildTimeLog,end,compile) $(call Host/Exports,$(HOST_STAMP_INSTALLED)) $(HOST_STAMP_INSTALLED): $(HOST_STAMP_BUILT) $(if $(FORCE_HOST_INSTALL),FORCE) + $(call BuildTimeLog,begin,install) $(call Host/Install,$(HOST_BUILD_PREFIX)) $(foreach hook,$(Hooks/HostInstall/Post),$(call $(hook))$(sep)) mkdir -p $$(shell dirname $$@) touch $(HOST_STAMP_BUILT) touch $$@ $(HOST_STAMP_PROGRAMS) + $(call BuildTimeLog,end,install) $(call DefaultTargets,$(patsubst %,host-%,$(DEFAULT_SUBDIR_TARGETS))) ifndef STAMP_BUILT diff --git a/include/kernel-build.mk b/include/kernel-build.mk index 404c318d413..bd859185ee8 100644 --- a/include/kernel-build.mk +++ b/include/kernel-build.mk @@ -90,12 +90,15 @@ define BuildKernel $(Kernel/Autoclean) $(STAMP_PREPARED): $(if $(LINUX_SITE),$(DL_DIR)/$(LINUX_SOURCE)) + $(call BuildTimeLog,begin,prepare) -rm -rf $(KERNEL_BUILD_DIR) -mkdir -p $(KERNEL_BUILD_DIR) $(Kernel/Prepare) touch $$@ + $(call BuildTimeLog,end,prepare) $(KERNEL_BUILD_DIR)/symtab.h: FORCE + $(call BuildTimeLog,begin,compile) rm -f $(KERNEL_BUILD_DIR)/symtab.h touch $(KERNEL_BUILD_DIR)/symtab.h +$(KERNEL_MAKE) vmlinux @@ -124,26 +127,33 @@ define BuildKernel awk '{print "*(___ksymtab_gpl+" $$$$1 ") \\" }'; \ echo; \ ) > $$@ + $(call BuildTimeLog,end,compile) $(STAMP_CONFIGURED): $(STAMP_PREPARED) $(LINUX_KCONFIG_LIST) $(TOPDIR)/.config FORCE + $(call BuildTimeLog,begin,configure) $(Kernel/Configure) touch $$@ + $(call BuildTimeLog,end,configure) $(LINUX_DIR)/.modules: export STAGING_PREFIX=$$(STAGING_DIR_HOST) $(LINUX_DIR)/.modules: export PKG_CONFIG_PATH=$$(STAGING_DIR_HOST)/lib/pkgconfig $(LINUX_DIR)/.modules: export PKG_CONFIG_LIBDIR=$$(STAGING_DIR_HOST)/lib/pkgconfig $(LINUX_DIR)/.modules: export FAIL_ON_UNCONFIGURED=1 $(LINUX_DIR)/.modules: $(STAMP_CONFIGURED) $(LINUX_DIR)/.config FORCE + $(call BuildTimeLog,begin,compile) $(Kernel/CompileModules) touch $$@ + $(call BuildTimeLog,end,compile) $(LINUX_DIR)/.image: export STAGING_PREFIX=$$(STAGING_DIR_HOST) $(LINUX_DIR)/.image: export PKG_CONFIG_PATH=$$(STAGING_DIR_HOST)/lib/pkgconfig $(LINUX_DIR)/.image: export PKG_CONFIG_LIBDIR=$$(STAGING_DIR_HOST)/lib/pkgconfig $(LINUX_DIR)/.image: $(STAMP_CONFIGURED) $(if $(CONFIG_STRIP_KERNEL_EXPORTS),$(KERNEL_BUILD_DIR)/symtab.h) FORCE + $(call BuildTimeLog,begin,compile) $(Kernel/CompileImage) $(Kernel/CollectDebug) touch $$@ + $(call BuildTimeLog,end,compile) mostlyclean: FORCE $(Kernel/Clean) diff --git a/include/package.mk b/include/package.mk index 9f284741df6..fe213f80411 100644 --- a/include/package.mk +++ b/include/package.mk @@ -247,6 +247,7 @@ define Build/CoreTargets $(STAMP_PREPARED) : export PATH=$$(TARGET_PATH_PKG) $(STAMP_PREPARED): $(STAMP_PREPARED_DEPENDS) + $(call BuildTimeLog,begin,prepare) @-rm -rf $(PKG_BUILD_DIR) @mkdir -p $(PKG_BUILD_DIR) touch $$@_check @@ -254,18 +255,22 @@ define Build/CoreTargets $(Build/Prepare) $(foreach hook,$(Hooks/Prepare/Post),$(call $(hook))$(sep)) touch $$@ + $(call BuildTimeLog,end,prepare) $(call Build/Exports,$(STAMP_CONFIGURED)) $(STAMP_CONFIGURED): $(STAMP_PREPARED) $(STAMP_CONFIGURED_DEPENDS) + $(call BuildTimeLog,begin,configure) rm -f $(STAMP_CONFIGURED_WILDCARD) $(CleanStaging) $(foreach hook,$(Hooks/Configure/Pre),$(call $(hook))$(sep)) $(Build/Configure) $(foreach hook,$(Hooks/Configure/Post),$(call $(hook))$(sep)) touch $$@ + $(call BuildTimeLog,end,configure) $(call Build/Exports,$(STAMP_BUILT)) $(STAMP_BUILT): $(STAMP_CONFIGURED) $(STAMP_BUILT_DEPENDS) + $(call BuildTimeLog,begin,compile) rm -f $$@ touch $$@_check $(foreach hook,$(Hooks/Compile/Pre),$(call $(hook))$(sep)) @@ -274,9 +279,11 @@ define Build/CoreTargets $(Build/Install) $(foreach hook,$(Hooks/Install/Post),$(call $(hook))$(sep)) touch $$@ + $(call BuildTimeLog,end,compile) $(STAMP_INSTALLED) : export PATH=$$(TARGET_PATH_PKG) $(STAMP_INSTALLED): $(STAMP_BUILT) + $(call BuildTimeLog,begin,install) rm -rf $(STAGING_TMP_DIR) mkdir -p $(STAGING_TMP_DIR)/host $(STAGING_DIR)/packages $(foreach hook,$(Hooks/InstallDev/Pre),\ @@ -300,6 +307,7 @@ define Build/CoreTargets fi rm -rf $(STAGING_TMP_DIR) touch $$@ + $(call BuildTimeLog,end,install) ifdef Build/InstallDev $(_pkg_target)compile: $(STAMP_INSTALLED) diff --git a/rules.mk b/rules.mk index cef05638354..6a959c2b9d2 100644 --- a/rules.mk +++ b/rules.mk @@ -196,6 +196,16 @@ STAGING_DIR_IMAGE:=$(STAGING_DIR)/image BUILD_LOG_DIR:=$(if $(call qstrip,$(CONFIG_BUILD_LOG_DIR)),$(call qstrip,$(CONFIG_BUILD_LOG_DIR)),$(TOPDIR)/logs) PKG_INFO_DIR := $(STAGING_DIR)/pkginfo +# Set BUILD_TIME_LOG= in the environment to record a begin and an end +# event for every prepare, configure, compile and install stage. Turn the log +# into a report with scripts/build-time-report.pl. +ifneq ($(BUILD_TIME_LOG),) + BUILD_TIME_LOG_FILE:=$(if $(filter /%,$(BUILD_TIME_LOG)),$(BUILD_TIME_LOG),$(TOPDIR)/$(BUILD_TIME_LOG)) + BuildTimeLog = @$(SCRIPT_DIR)/build-time-log.sh $(BUILD_TIME_LOG_FILE) $(1) $(2) "$(if $(BUILD_SUBDIR),$(BUILD_SUBDIR),$(CURDIR))$(if $(BUILD_VARIANT),/$(BUILD_VARIANT))" +else + BuildTimeLog = +endif + BUILD_DIR_HOST:=$(if $(IS_PACKAGE_BUILD),$(BUILD_DIR_BASE)/hostpkg,$(BUILD_DIR_BASE)/host) STAGING_DIR_HOST:=$(abspath $(STAGING_DIR)/../host) STAGING_DIR_HOSTPKG:=$(abspath $(STAGING_DIR)/../hostpkg) diff --git a/scripts/build-time-log.sh b/scripts/build-time-log.sh new file mode 100755 index 00000000000..20c61a261dd --- /dev/null +++ b/scripts/build-time-log.sh @@ -0,0 +1,18 @@ +#!/bin/sh +# +# SPDX-License-Identifier: GPL-2.0-only +# +# Records one build stage event. See scripts/build-time-report.pl. +# +# Usage: build-time-log.sh + +[ $# -eq 4 ] || exit 0 + +now=$(date +%s.%N 2>/dev/null) +case "$now" in + ''|*N*) now=$(date +%s) ;; +esac + +printf '%s\t%s\t%s\t%s\n' "$now" "$2" "$3" "$4" >> "$1" 2>/dev/null + +exit 0 diff --git a/scripts/build-time-report.pl b/scripts/build-time-report.pl new file mode 100755 index 00000000000..3f2e2a1c53b --- /dev/null +++ b/scripts/build-time-report.pl @@ -0,0 +1,181 @@ +#!/usr/bin/env perl +# +# SPDX-License-Identifier: GPL-2.0-only +# +# Turns a BUILD_TIME_LOG file into a report. +# +# Usage: build-time-report.pl [-n ] [-s ] +# +# Wall share is the share of the build duration that a stage is responsible +# for. Each second of the build is divided between the stages that run in it, +# so the wall shares of all stages add up to the busy time. A stage that runs +# alone on an idle machine gets the whole second. Solo time counts only the +# seconds in which a stage is the one thing that runs, so it is the part of +# the build that a faster stage shortens directly. + +use strict; +use warnings; + +my $top = 20; +my $only_stage; + +while (@ARGV && $ARGV[0] =~ /^-/) { + my $opt = shift @ARGV; + if ($opt eq '-n') { $top = shift @ARGV } + elsif ($opt eq '-s') { $only_stage = shift @ARGV } + else { die "Usage: $0 [-n ] [-s ] \n" } +} + +my $file = shift @ARGV or die "Usage: $0 [-n ] [-s ] \n"; + +open(my $fh, '<', $file) or die "$0: cannot read $file: $!\n"; + +my (@iv, %pending); + +while (my $line = <$fh>) { + chomp $line; + my ($time, $event, $stage, $name) = split(/\t/, $line, 4); + next unless defined $name; + next unless defined $time && $time =~ /^[0-9]+(\.[0-9]+)?$/; + next if defined $only_stage && $stage ne $only_stage; + + my $key = "$stage\t$name"; + + if ($event eq 'begin') { + push @{$pending{$key}}, $time; + next; + } + + next unless $event eq 'end'; + my $start = $pending{$key} ? pop @{$pending{$key}} : undef; + next unless defined $start; + + push @iv, { + idx => scalar @iv, + start => $start, + end => $time, + dur => $time - $start, + stage => $stage, + name => $name, + share => 0, + solo => 0, + }; +} + +close($fh); + +my $incomplete = 0; +$incomplete += scalar @{$pending{$_}} for keys %pending; + +die "$0: no completed stages in $file\n" unless @iv; + +my @events; +for my $iv (@iv) { + push @events, [ $iv->{start}, 1, $iv ]; + push @events, [ $iv->{end}, 0, $iv ]; +} + +# An end event sorts before a begin event at the same instant. One stage that +# hands over to the next one must not look like parallel work. +@events = sort { $a->[0] <=> $b->[0] || $a->[1] <=> $b->[1] } @events; + +my (%active, $idle, $busy); +$idle = 0; +$busy = 0; + +my $prev = $events[0][0]; + +for my $ev (@events) { + my ($t, $is_start, $iv) = @$ev; + my $dt = $t - $prev; + + if ($dt > 0) { + my @cur = values %active; + my $n = scalar @cur; + + if (!$n) { + $idle += $dt; + } + else { + $busy += $dt; + my $part = $dt / $n; + $_->{share} += $part for @cur; + $cur[0]->{solo} += $dt if $n == 1; + } + } + + if ($is_start) { $active{$iv->{idx}} = $iv } + else { delete $active{$iv->{idx}} } + + $prev = $t; +} + +my $total = $events[-1][0] - $events[0][0]; +my $sum_dur = 0; +$sum_dur += $_->{dur} for @iv; + +my (%st, %pkg); + +for my $iv (@iv) { + my $s = $st{$iv->{stage}} ||= { count => 0, dur => 0, share => 0, solo => 0 }; + $s->{count}++; + $s->{dur} += $iv->{dur}; + $s->{share} += $iv->{share}; + $s->{solo} += $iv->{solo}; + + my $key = sprintf("%s [%s]", $iv->{name}, $iv->{stage}); + my $p = $pkg{$key} ||= { dur => 0, share => 0, solo => 0 }; + $p->{dur} += $iv->{dur}; + $p->{share} += $iv->{share}; + $p->{solo} += $iv->{solo}; +} + +sub hms { + my $s = shift; + return sprintf("%d:%02d:%05.2f", + int($s / 3600), int($s / 60) % 60, $s - 60 * int($s / 60)); +} + +sub pct { + my ($a, $b) = @_; + return $b > 0 ? 100 * $a / $b : 0; +} + +printf "build window %s\n", hms($total); +printf "busy %s (%.1f%%)\n", hms($busy), pct($busy, $total); +printf "idle %s (%.1f%%)\n", hms($idle), pct($idle, $total); +printf "stage time %s\n", hms($sum_dur); +printf "mean parallelism %.2f\n", $busy > 0 ? $sum_dur / $busy : 0; +printf "stages completed %d\n", scalar @iv; +printf "stages unfinished %d\n", $incomplete if $incomplete; +print "\n"; + +printf "%-10s %6s %12s %12s %8s %12s %8s\n", + 'stage', 'count', 'sum', 'wall share', 'of wall', 'solo', 'of wall'; + +for my $name (sort { $st{$b}{share} <=> $st{$a}{share} } keys %st) { + my $s = $st{$name}; + printf "%-10s %6d %12s %12s %7.1f%% %12s %7.1f%%\n", + $name, $s->{count}, hms($s->{dur}), hms($s->{share}), + pct($s->{share}, $total), hms($s->{solo}), pct($s->{solo}, $total); +} + +sub table { + my ($title, $key, $ref) = @_; + + print "\n$title\n"; + printf "%-56s %12s %12s %12s\n", 'stage', 'duration', 'wall share', 'solo'; + + my @k = sort { $ref->{$b}{$key} <=> $ref->{$a}{$key} } keys %$ref; + splice(@k, $top) if @k > $top; + + for my $name (@k) { + my $e = $ref->{$name}; + printf "%-56s %12s %12s %12s\n", + $name, hms($e->{dur}), hms($e->{share}), hms($e->{solo}); + } +} + +table("top $top by wall share", 'share', \%pkg); +table("top $top by solo time", 'solo', \%pkg); +table("top $top by duration", 'dur', \%pkg);