EMERGE_DEFAULT_OPTS
Warning: Display title "EMERGE_DEFAULT_OPTS" overrides earlier display title "EMERGE DEFAULT OPTS".
EMERGE_DEFAULT_OPTS is a variable for Portage that defines entries to be appended to the emerge command line.
EMERGE_DEFAULT_OPTS allows for parallel emerge operations through the --jobs N
and --load-average X.Y
options. EMERGE_DEFAULT_OPTS is used by Portage to reference system load, or load average, and limit how many packages are built at a time.
Common use cases
Parallel builds
The --jobs N
argument (short form: -jN
) will emerge N jobs at a time. Providing no arguments to -j
floods the processor with as many jobs as possible. This is not recommended. Values for N should be no more than 2GB of ram per processor core. Packages can reach this constraint.
Um beispielsweise bis zu drei Build-Jobs gleichzeitig auszuführen:
EMERGE_DEFAULT_OPTS="--jobs 3"
When used with --load-average X.Y
(short form: -lX.Y
), emerge tries to limit the load average of the system below the floating point number X.Y. The running jobs are again limited by the --jobs
parameter.
The load average value is the same as displayed by top or uptime, and for an N-core system, a load average of N.0
would be a 100% load. Setting X.Y=N*0.9
to limit the load to 90% maintains system responsiveness.
When
MAKEOPTS="-jN"
is used with EMERGE_DEFAULT_OPTS="--jobs K --load-average X.Y"
the number of possible tasks created would be up to N*K
. Therefore, both variables need to be set with each other in mind as they create up to K jobs each with up to N tasks.MAKEOPTS
and EMERGE_DEFAULT_OPTS
are suited for long emerges including multiple source code files and make the most of the --jobs
parameter. They should be used with caution and be commented out when they cause emerge errors.
See also
- MAKEOPTS — a variable that defines and limits how many parallel make jobs can be launched from Portage.
- Knowledge Base:Emerge out of memory
- Portage niceness — describes some configuration options available for system administrators to help manage Portage's resource usage.