Add jobs.mk to allow for target-jobs

jobs.mk automates -j$JOB_MAX and capturing build log based on target.

Compute a default for JOB_MAX in local.sys.mk

Reviewed by:	stevek, imp
Differential Revision:	https://reviews.freebsd.org/D39683

4 files changed, 127 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 8232041e0a35..0b2438a0cfc0 100644
--- a/Makefile
+++ b/Makefile
@@ -119,6 +119,16 @@
 # For more information, see the build(7) manual page.
 #
 
+# Include jobs.mk early if we need it.
+# It will turn:
+# 	make buildworld-jobs
+# into
+# 	make -j${JOB_MAX} buildworld > ../buildworld.log 2>&1
+#
+.if make(*-jobs)
+.include <jobs.mk>
+.endif
+
 .if defined(UNIVERSE_TARGET) || defined(MAKE_JUST_WORLDS) || defined(WITHOUT_KERNELS)
 __DO_KERNELS=no
 .endif
diff --git a/UPDATING b/UPDATING
index 092115d899ea..70e5a58352af 100644
--- a/UPDATING
+++ b/UPDATING
@@ -27,6 +27,15 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 14.x IS SLOW:
 	world, or to merely disable the most expensive debugging functionality
 	at runtime, run "ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20230420:
+	Add jobs.mk to save typing. Enables -j${JOB_MAX} and logging
+	eg.
+		make buildworld-jobs
+	runs
+		make -j${JOB_MAX} buildworld > ../buildworld.log 2>&1
+
+	where JOB_MAX is derrived from ncpus in local.sys.mk if not set in env.
+
 20230316:
 	Video related devices for some arm devices have been renamed.
 	If you have a custom kernel config and want to use hdmi output on
diff --git a/share/mk/jobs.mk b/share/mk/jobs.mk
new file mode 100644
index 000000000000..f465ea06310b
--- /dev/null
+++ b/share/mk/jobs.mk
@@ -0,0 +1,88 @@
+# $Id: jobs.mk,v 1.7 2023/04/18 23:32:28 sjg Exp $
+#
+#	@(#) Copyright (c) 2012-2023, Simon J. Gerraty
+#
+#	This file is provided in the hope that it will
+#	be of use.  There is absolutely NO WARRANTY.
+#	Permission to copy, redistribute or otherwise
+#	use this file is hereby granted provided that
+#	the above copyright notice and this notice are
+#	left intact.
+#
+#	Please send copies of changes and bug-fixes to:
+#	sjg@crufty.net
+#
+
+# This makefile is used by top-level makefile.
+# With the following:
+#
+#	.if make(*-jobs)
+#	.include <jobs.mk>
+#	.endif
+#
+# 
+# Then if you do:
+#
+#	mk target-jobs
+#
+# We will run:
+#
+#	${MAKE} -j${JOB_MAX} target > ${JOB_LOGDIR}/target.log 2>&1
+#
+# JOB_MAX defaults to 8 but should normally be derrived based on the
+# number of cpus available.  The wrapper script 'mk' makes that easy.
+#
+
+now_utc ?= ${%s:L:gmtime}
+.if !defined(start_utc)
+start_utc := ${now_utc}
+.endif
+
+.info ${.newline}${TIME_STAMP} Start ${.TARGETS}
+
+.if make(*-jobs)
+
+JOB_LOGDIR ?= ${SRCTOP:H}
+JOB_LOG = ${JOB_LOGDIR}/${.TARGET:S,-jobs,,:S,/,_,g}.log
+JOB_LOG_GENS ?= 4
+# we like to rotate logs
+.if empty(NEWLOG_SH)
+.ifdef M_whence
+NEWLOG_SH := ${newlog.sh:L:${M_whence}}
+.else
+NEWLOG_SH := ${(type newlog.sh) 2> /dev/null:L:sh:M/*}
+.endif
+.endif
+.if !empty(NEWLOG_SH) && exists(${NEWLOG_SH})
+NEWLOG := sh ${NEWLOG_SH}
+JOB_NEWLOG_ARGS ?= -S -n ${JOB_LOG_GENS}
+.else
+NEWLOG = :
+.endif
+
+.if ${.MAKE.JOBS:U0} > 0
+JOB_MAX= ${.MAKE.JOBS}
+.else
+# This should be derrived from number of cpu's
+JOB_MAX?= 8
+JOB_ARGS+= -j${JOB_MAX}
+.endif
+
+# we need to reset .MAKE.LEVEL to 0 do that
+# build orchestration works as expected (DIRDEPS_BUILD)
+${.TARGETS:M*-jobs}:
+	@${NEWLOG} ${JOB_NEWLOG_ARGS} ${JOB_LOG}
+	@echo Logging to ${JOB_LOG}
+	@cd ${.CURDIR} && env MAKELEVEL=0 \
+	${.MAKE} ${JOB_ARGS} _TARGETS=${.TARGET:S,-jobs,,} ${.TARGET:S,-jobs,,} >> ${JOB_LOG} 2>&1
+
+.endif
+
+.END: _build_finish
+.ERROR: _build_failed
+
+_build_finish:  .NOMETA
+	@echo "${TIME_STAMP} Finished ${.TARGETS} seconds=`expr ${now_utc} - ${start_utc}`"
+
+_build_failed: .NOMETA
+	@echo "${TIME_STAMP} Failed ${.TARGETS} seconds=`expr ${now_utc} - ${start_utc}`"
diff --git a/share/mk/local.sys.mk b/share/mk/local.sys.mk
index 39605c05e129..1817f6393949 100644
--- a/share/mk/local.sys.mk
+++ b/share/mk/local.sys.mk
@@ -59,6 +59,26 @@ _PREMK_LIBDIR:=	${LIBDIR}
 .include "src.sys.mk"
 .-include <site.sys.mk>
 
+.if make(*-jobs) && empty(JOB_MAX)
+# provide a reasonable? default for JOB_MAX based on ncpu
+JOB_MAX_FACTOR?= 1.33
+NPROC?= ${(type nproc) 2> /dev/null:L:sh:M/*:[1]}
+NPROC:= ${NPROC}
+.if !empty(NPROC)
+ncpu!= ${NPROC}
+.elif ${.MAKE.OS:NDarwin:NFreeBSD} == ""
+ncpu!= sysctl -n hw.ncpu
+.endif
+.if ${ncpu:U0} > 1
+.if ${JOB_MAX_FACTOR} == 1
+JOB_MAX:= ${ncpu}
+.else
+jm!= echo ${ncpu} \* ${JOB_MAX_FACTOR} | bc
+JOB_MAX:= ${jm:R}
+.endif
+.endif
+.endif
+
 .if ${.MAKE.MODE:Mmeta*} != ""
 # we can afford to use cookies to prevent some targets
 # re-running needlessly but only when using filemon.