MAKEOPTS
MAKEOPTS is a variable that defines and limits how many parallel make jobs can be launched from Portage. It can be set in the /etc/portage/make.conf configuration file.
As a rule of thumb, MAKEOPTS jobs should be limited to less than or equal to the minimum of the size of RAM/2GB or CPU thread count.
The parallel jobs entry ensures that, when make is invoked, it knows how many parallel sessions it is allowed to trigger (when parallel sessions are possible of course). This is completely within the scope of that make command and has no influence on parallel installations (which is triggered through emerge with --jobs=X option). The recommended value is the number of logical processors in the CPU.
On a system with one Intel Core i7 CPU the following command shows the numbering of the available logical CPUs.
root #lscpuArchitecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 8 On-line CPU(s) list: 0-8 Thread(s) per core: 2 Core(s) per socket: 4 Socket(s): 1
The make program creates parallel tasks based on the system's current load average and the --load-average limit. Since the load average is a damped value, the load-average jobs limitation can be sensibly set slightly above the number of available CPUs. For 4 physical cores with 2 threads per core, or 8 logical cores, the MAKEOPTS variable could be set to:
/etc/portage/make.confMAKEOPTS="--jobs 8 --load-average 9"
Jobs should also be limited by RAM. Recent gcc versions can take 1.5 GB to 2 GB of RAM per job. For systems with 8 logical CPUs and only 4 GB RAM, MAKEOPTS should be lowered to -j2 so that the system can run the basics and also compile without hitting swap very often slowing things down. To measure the time needed to compile the app-misc/mc package with 4 jobs:
root #time MAKEOPTS="-j4" emerge app-misc/mcMAKEOPTS on a per-package basis
Packages can be emerged with different MAKEOPTS values on a per-package basis. See /etc/portage/package.env for details.
See also
- EMERGE_DEFAULT_OPTS — a variable for Portage that defines entries to be appended to the emerge command line.
- Knowledge Base:Emerge out of memory
- Portage niceness — describes some configuration options available for system administrators to help manage Portage's resource usage.