OpenCloudOS-Kernel/drivers/gpu/drm/i915/Kconfig.profile

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config DRM_I915_USERFAULT_AUTOSUSPEND
int "Runtime autosuspend delay for userspace GGTT mmaps (ms)"
default 250 # milliseconds
help
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.
config DRM_I915_HEARTBEAT_INTERVAL
int "Interval between heartbeat pulses (ms)"
default 2500 # milliseconds
help
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.
config DRM_I915_PREEMPT_TIMEOUT
int "Preempt timeout (ms, jiffy granularity)"
default 100 # milliseconds
help
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.
drm/i915: Expose the busyspin durations for i915_wait_request An interesting discussion regarding "hybrid interrupt polling" for NVMe came to the conclusion that the ideal busyspin before sleeping was half of the expected request latency (and better if it was already halfway through that request). This suggested that we too should look again at our tradeoff between spinning and waiting. Currently, our spin simply tries to hide the cost of enabling the interrupt, which is good to avoid penalising nop requests (i.e. test throughput) and not much else. Studying real world workloads suggests that a spin of upto 500us can dramatically boost performance, but the suggestion is that this is not from avoiding interrupt latency per-se, but from secondary effects of sleeping such as allowing the CPU reduce cstate and context switch away. In a truly hybrid interrupt polling scheme, we would aim to sleep until just before the request completed and then wake up in advance of the interrupt and do a quick poll to handle completion. This is tricky for ourselves at the moment as we are not recording request times, and since we allow preemption, our requests are not on as a nicely ordered timeline as IO. However, the idea is interesting, for it will certainly help us decide when busyspinning is worthwhile. v2: Expose the spin setting via Kconfig options for easier adjustment and testing. v3: Don't get caught sneaking in a change to the busyspin parameters. v4: Explain more about the "hybrid interrupt polling" scheme that we want to migrate towards. Suggested-by: Sagar Kamble <sagar.a.kamble@intel.com> References: http://events.linuxfoundation.org/sites/events/files/slides/lemoal-nvme-polling-vault-2017-final_0.pdf Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Sagar Kamble <sagar.a.kamble@intel.com> Cc: Eero Tamminen <eero.t.tamminen@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Ben Widawsky <ben@bwidawsk.net> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Michał Winiarski <michal.winiarski@intel.com> Reviewed-by: Sagar Kamble <sagar.a.kamble@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190419182625.11186-1-chris@chris-wilson.co.uk
2019-04-20 02:26:25 +08:00
config DRM_I915_SPIN_REQUEST
int "Busywait for request completion (us)"
drm/i915: Expose the busyspin durations for i915_wait_request An interesting discussion regarding "hybrid interrupt polling" for NVMe came to the conclusion that the ideal busyspin before sleeping was half of the expected request latency (and better if it was already halfway through that request). This suggested that we too should look again at our tradeoff between spinning and waiting. Currently, our spin simply tries to hide the cost of enabling the interrupt, which is good to avoid penalising nop requests (i.e. test throughput) and not much else. Studying real world workloads suggests that a spin of upto 500us can dramatically boost performance, but the suggestion is that this is not from avoiding interrupt latency per-se, but from secondary effects of sleeping such as allowing the CPU reduce cstate and context switch away. In a truly hybrid interrupt polling scheme, we would aim to sleep until just before the request completed and then wake up in advance of the interrupt and do a quick poll to handle completion. This is tricky for ourselves at the moment as we are not recording request times, and since we allow preemption, our requests are not on as a nicely ordered timeline as IO. However, the idea is interesting, for it will certainly help us decide when busyspinning is worthwhile. v2: Expose the spin setting via Kconfig options for easier adjustment and testing. v3: Don't get caught sneaking in a change to the busyspin parameters. v4: Explain more about the "hybrid interrupt polling" scheme that we want to migrate towards. Suggested-by: Sagar Kamble <sagar.a.kamble@intel.com> References: http://events.linuxfoundation.org/sites/events/files/slides/lemoal-nvme-polling-vault-2017-final_0.pdf Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Sagar Kamble <sagar.a.kamble@intel.com> Cc: Eero Tamminen <eero.t.tamminen@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Ben Widawsky <ben@bwidawsk.net> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Michał Winiarski <michal.winiarski@intel.com> Reviewed-by: Sagar Kamble <sagar.a.kamble@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190419182625.11186-1-chris@chris-wilson.co.uk
2019-04-20 02:26:25 +08:00
default 5 # microseconds
help
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.
config DRM_I915_STOP_TIMEOUT
int "How long to wait for an engine to quiesce gracefully before reset (ms)"
default 100 # milliseconds
help
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.