RT

The rt modules can give real-time priorities to processing threads.

It uses the operating system's scheduler to enable realtime scheduling for certain threads to assist with low latency audio processing. This requires RLIMIT_RTPRIO to be set to a value that's equal to this module's rt.prio parameter or higher. Most distros will come with some package that configures this for certain groups or users. If this is not set up and DBus is available, then this module will fall back to using the Portal Realtime DBus API or RTKit.

Module Name

libpipewire-module-rt

Module Options

• nice.level: The nice value set for the application thread. It improves performance of the communication with the pipewire daemon.
• rt.prio: The realtime priority of the data thread. Higher values are higher priority.
• rt.time.soft, rt.time.hard: The amount of CPU time an RT thread can consume without doing any blocking calls before the kernel kills the thread. This is a safety measure to avoid lockups of the complete system when some thread consumes 100%.
• rlimits.enabled: enable the use of rtlimits, default true.
• rtportal.enabled: enable the use of realtime portal, default true
• rtkit.enabled: enable the use of rtkit, default true
• uclamp.min: the minimum utilisation value the scheduler should consider
• uclamp.max: the maximum utilisation value the scheduler should consider

The nice level is by default set to an invalid value so that clients don't automatically have the nice level raised.

The PipeWire server processes are explicitly configured with a valid nice level.

Example configuration

context.modules = [
{   name = libpipewire-module-rt
    args = {
        #nice.level   = 20
        #rt.prio      = 88
        #rt.time.soft = -1
        #rt.time.hard = -1
        #rlimits.enabled = true
        #rtportal.enabled = true
        #rtkit.enabled = true
        #uclamp.min = 0
        #uclamp.max = 1024
    }
    flags = [ ifexists nofail ]
}
]