Busywait for request completion limit (ns)
configname: CONFIG_DRM_I915_MAX_REQUEST_BUSYWAIT
Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
└─>drm/i915 Profile Guided Optimisation
└─>Busywait for request completion limit (ns)
In linux kernel since version 4.14.326 (release Date: 2023-09-23)
Before sleeping waiting for a request (GPU operation) to complete,
we may spend some time polling for its completion. As the IRQ may
take a non-negligible time to setup, we do a short spin first to
check if the request will complete in the time it would have taken
us to enable the interrupt.
This is adjustable via
/sys/class/drm/card?/engine/*/max_busywait_duration_ns
May be 0 to disable the initial spin. In practice, we estimate
the cost of enabling the interrupt (if currently disabled) to be
a few microseconds.
we may spend some time polling for its completion. As the IRQ may
take a non-negligible time to setup, we do a short spin first to
check if the request will complete in the time it would have taken
us to enable the interrupt.
This is adjustable via
/sys/class/drm/card?/engine/*/max_busywait_duration_ns
May be 0 to disable the initial spin. In practice, we estimate
the cost of enabling the interrupt (if currently disabled) to be
a few microseconds.