blob: c280b6ae38ebe9dc6659c257ced8c2cef9bab644 [file] [log] [blame]
int "Runtime autosuspend delay for userspace GGTT mmaps (ms)"
default 250 # milliseconds
On runtime suspend, as we suspend the device, we have to revoke
userspace GGTT mmaps and force userspace to take a pagefault on
their next access. The revocation and subsequent recreation of
the GGTT mmap can be very slow and so we impose a small hysteris
that complements the runtime-pm autosuspend and provides a lower
floor on the autosuspend delay.
May be 0 to disable the extra delay and solely use the device level
runtime pm autosuspend delay tunable.
int "Interval between heartbeat pulses (ms)"
default 2500 # milliseconds
The driver sends a periodic heartbeat down all active engines to
check the health of the GPU and undertake regular house-keeping of
internal driver state.
May be 0 to disable heartbeats and therefore disable automatic GPU
hang detection.
int "Preempt timeout (ms, jiffy granularity)"
default 640 # milliseconds
How long to wait (in milliseconds) for a preemption event to occur
when submitting a new context via execlists. If the current context
does not hit an arbitration point and yield to HW before the timer
expires, the HW will be reset to allow the more important context
to execute.
May be 0 to disable the timeout.
int "Busywait for request completion (us)"
default 5 # microseconds
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.
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.
int "How long to wait for an engine to quiesce gracefully before reset (ms)"
default 100 # milliseconds
By stopping submission and sleeping for a short time before resetting
the GPU, we allow the innocent contexts also on the system to quiesce.
It is then less likely for a hanging context to cause collateral
damage as the system is reset in order to recover. The corollary is
that the reset itself may take longer and so be more disruptive to
interactive or low latency workloads.
int "Scheduling quantum for userspace batches (ms, jiffy granularity)"
default 1 # milliseconds
When two user batches of equal priority are executing, we will
alternate execution of each batch to ensure forward progress of
all users. This is necessary in some cases where there may be
an implicit dependency between those batches that requires
concurrent execution in order for them to proceed, e.g. they
interact with each other via userspace semaphores. Each context
is scheduled for execution for the timeslice duration, before
switching to the next context.
May be 0 to disable timeslicing.