522266 – sys-devel/make - avoid waved load at using parallel emerge

Created attachment 384300 [details, diff]
make-3.82-load2jobs.patch

When I tested the parallel emerge to find the good configuration, I felt difficulty controling the number of jobs.

Because the count of raised "make $MAKEOPTS" vary at parallel emerge such as "emerge --jobs=8", "--jobs=?" in $MAKEOPTS can't control the total of jobs.
When emerge raises N "make --jobs=K", these N "make"s do as if one "make --jobs=(N times K)" do, and exceeds system-load or lets some cpu-cores idle.

For such case, "make" must have "--load-average" option.
But "load-average" is not the system-load at the moment in Linux.
It is the average of sytem-load during the last 1 minite.
So, load-average in Linux has almost 1 minite time-lag.
In addition, there are several "make" command running at same time, which amplify job-raising speed.
These break the system-load controling algorithm in "make" command, let "make" commands begin to resonate with each other, make system go to round-trip between overload and idling.

To prevent these "make" from resonating, I suggest calculating next number of jobs without current number of jobs like "--jobs" option, unlike calculating job-raising speed which original algorithm does.

Portage 2.2.8-r1 (default/linux/amd64/13.0, gcc-4.7.3, glibc-2.19-r1, 3.14.14-gentoo x86_64)
=================================================================
System uname: Linux-3.14.14-gentoo-x86_64-AMD_FX-tm-8350_Eight-Core_Processor-with-gentoo-2.2
KiB Mem:    16298304 total,  15224824 free
KiB Swap:          0 total,         0 free
Timestamp of tree: Sat, 30 Aug 2014 01:45:01 +0000
ld GNU ld (GNU Binutils) 2.23.2
app-shells/bash:          4.2_p45
dev-lang/python:          2.7.7, 3.3.5-r1
dev-util/cmake:           2.8.12.2-r1
dev-util/pkgconfig:       0.28-r1
sys-apps/baselayout:      2.2
sys-apps/openrc:          0.12.4
sys-apps/sandbox:         2.6-r1
sys-devel/autoconf:       2.13, 2.69
sys-devel/automake:       1.11.6, 1.13.4
sys-devel/binutils:       2.23.2
sys-devel/gcc:            4.7.3-r1
sys-devel/gcc-config:     1.7.3
sys-devel/libtool:        2.4.2-r1
sys-devel/make:           3.82-r4::x-portage
sys-kernel/linux-headers: 3.13 (virtual/os-headers)
sys-libs/glibc:           2.19-r1
Repositories: gentoo x-portage
ACCEPT_KEYWORDS="amd64"
ACCEPT_LICENSE="* -@EULA"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-O2 -pipe -march=bdver2"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/share/gnupg/qualified.txt"
CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo"
CXXFLAGS="-O2 -pipe -march=bdver2"
DISTDIR="/usr/portage/distfiles"
FCFLAGS="-O2 -pipe"
FEATURES="assume-digests binpkg-logs config-protect-if-modified distlocks ebuild-locks fixlafiles merge-sync news parallel-fetch preserve-libs protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync"
FFLAGS="-O2 -pipe"
GENTOO_MIRRORS="http://ftp.jaist.ac.jp/pub/Linux/Gentoo/ http://gentoo.gg3.net/"
LANG="ja_JP.EUC-JP"
LC_ALL="ja_JP.EUC-JP"
LDFLAGS="-Wl,-O1 -Wl,--as-needed"
MAKEOPTS="-j8"
PKGDIR="/usr/portage/packages"
PORTAGE_CONFIGROOT="/"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage"
SYNC="rsync://rsync.jp.gentoo.org/gentoo-portage"
USE="X acl acpi alsa amd64 avx berkdb bzip2 cairo cjk cli cracklib crypt cups cxx dri gcj gdbm gtk iconv ipv6 jpeg mmx modules multilib ncurses nls nptl opengl openmp pam pcre png python readline seamonkey session sound sse sse2 sse3 sse4_1 ssl ssse3 tcpd threads uim unicode zlib" ABI_X86="64" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump author" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="ja" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-5" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_3" QEMU_SOFTMMU_TARGETS="x86_64 i386 arm" QEMU_USER_TARGETS="arm i386 x86_64" RUBY_TARGETS="ruby19 ruby20" USERLAND="GNU" VIDEO_CARDS="radeon vesa" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account"
Unset:  CPPFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, USE_PYTHON