linux-toradex.git/drivers/gpu/drm/i915/Kconfig.profile, branch master Linux kernel for Apalis and Colibri modules drm/i915: Improve long running compute w/a for GuC submission 2022-10-24T19:12:47+00:00 John Harrison John.C.Harrison@Intel.com 2022-10-06T21:38:13+00:00 d7a8680ec9fb217987a9569aba1abeed886805f0 A workaround was added to the driver to allow compute workloads to run 'forever' by disabling pre-emption on the RCS engine for Gen12. It is not totally unbound as the heartbeat will kick in eventually and cause a reset of the hung engine. However, this does not work well in GuC submission mode. In GuC mode, the pre-emption timeout is how GuC detects hung contexts and triggers a per engine reset. Thus, disabling the timeout means also losing all per engine reset ability. A full GT reset will still occur when the heartbeat finally expires, but that is a much more destructive and undesirable mechanism. The purpose of the workaround is actually to give compute tasks longer to reach a pre-emption point after a pre-emption request has been issued. This is necessary because Gen12 does not support mid-thread pre-emption and compute tasks can have long running threads. So, rather than disabling the timeout completely, just set it to a 'long' value. v2: Review feedback from Tvrtko - must hard code the 'long' value instead of determining it algorithmically. So make it an extra CONFIG definition. Also, remove the execlist centric comment from the existing pre-emption timeout CONFIG option given that it applies to more than just execlists. Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> Acked-by: Michal Mrozek <michal.mrozek@intel.com> Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221006213813.1563435-5-John.C.Harrison@Intel.com 
A workaround was added to the driver to allow compute workloads to run
'forever' by disabling pre-emption on the RCS engine for Gen12.
It is not totally unbound as the heartbeat will kick in eventually
and cause a reset of the hung engine.

However, this does not work well in GuC submission mode. In GuC mode,
the pre-emption timeout is how GuC detects hung contexts and triggers
a per engine reset. Thus, disabling the timeout means also losing all
per engine reset ability. A full GT reset will still occur when the
heartbeat finally expires, but that is a much more destructive and
undesirable mechanism.

The purpose of the workaround is actually to give compute tasks longer
to reach a pre-emption point after a pre-emption request has been
issued. This is necessary because Gen12 does not support mid-thread
pre-emption and compute tasks can have long running threads.

So, rather than disabling the timeout completely, just set it to a
'long' value.

v2: Review feedback from Tvrtko - must hard code the 'long' value
instead of determining it algorithmically. So make it an extra CONFIG
definition. Also, remove the execlist centric comment from the
existing pre-emption timeout CONFIG option given that it applies to
more than just execlists.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Acked-by: Michal Mrozek <michal.mrozek@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221006213813.1563435-5-John.C.Harrison@Intel.com
drm/i915: Fail too long user submissions by default 2021-03-26T00:01:27+00:00 Tvrtko Ursulin tvrtko.ursulin@intel.com 2021-03-24T12:13:34+00:00 e8dbb566b338cc25f78278378dfcc21bfa8d62a0 A new Kconfig option CONFIG_DRM_I915_REQUEST_TIMEOUT is added, defaulting to 20s, and this timeout is applied to all users contexts using the previously added watchdog facility. Result of this is that any user submission will simply fail after this timeout, either causing a reset (for non-preemptable), or incomplete results. This can have an effect that workloads which used to work fine will suddenly start failing. Even workloads comprised of short batches but in long dependency chains can be terminated. And because of lack of agreement on usefulness and safety of fence error propagation this partial execution can be invisible to userspace even if it is "listening" to returned fence status. Another interaction is with hangcheck where care needs to be taken timeout is not set lower or close to three times the heartbeat interval. Otherwise a hang in any application can cause complete termination of all submissions from unrelated clients. Any users modifying the per engine heartbeat intervals therefore need to be aware of this potential denial of service to avoid inadvertently enabling it. Given all this I am personally not convinced the scheme is a good idea. Intuitively it feels object importers would be better positioned to enforce the time they are willing to wait for something to complete. v2: * Improved commit message and Kconfig text. * Pull in some helper code from patch which got dropped. v3: * Bump timeout to 20s to see if it helps Tigerlake. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Matthew Auld <matthew.auld@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210324121335.2307063-7-tvrtko.ursulin@linux.intel.com 
A new Kconfig option CONFIG_DRM_I915_REQUEST_TIMEOUT is added, defaulting
to 20s, and this timeout is applied to all users contexts using the
previously added watchdog facility.

Result of this is that any user submission will simply fail after this
timeout, either causing a reset (for non-preemptable), or incomplete
results.

This can have an effect that workloads which used to work fine will
suddenly start failing. Even workloads comprised of short batches but in
long dependency chains can be terminated.

And because of lack of agreement on usefulness and safety of fence error
propagation this partial execution can be invisible to userspace even if
it is "listening" to returned fence status.

Another interaction is with hangcheck where care needs to be taken timeout
is not set lower or close to three times the heartbeat interval. Otherwise
a hang in any application can cause complete termination of all
submissions from unrelated clients. Any users modifying the per engine
heartbeat intervals therefore need to be aware of this potential denial of
service to avoid inadvertently enabling it.

Given all this I am personally not convinced the scheme is a good idea.
Intuitively it feels object importers would be better positioned to
enforce the time they are willing to wait for something to complete.

v2:
 * Improved commit message and Kconfig text.
 * Pull in some helper code from patch which got dropped.

v3:
 * Bump timeout to 20s to see if it helps Tigerlake.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210324121335.2307063-7-tvrtko.ursulin@linux.intel.com
drm/i915: Replace the hardcoded I915_FENCE_TIMEOUT 2020-05-09T11:57:57+00:00 Chris Wilson chris@chris-wilson.co.uk 2020-05-09T10:50:21+00:00 16dc224f1c0ff8d242ef41c40d4da0264d351daa Expose the hardcoded timeout for unsignaled foreign fences as a Kconfig option, primarily to allow brave systems to disable the timeout and solely rely on correct signaling. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Acked-by: Michael J. Ruhl <michael.j.ruhl@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200509105021.12542-1-chris@chris-wilson.co.uk 
Expose the hardcoded timeout for unsignaled foreign fences as a Kconfig
option, primarily to allow brave systems to disable the timeout and
solely rely on correct signaling.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200509105021.12542-1-chris@chris-wilson.co.uk
drm/i915/gen12: Disable preemption timeout 2020-03-12T13:46:01+00:00 Tvrtko Ursulin tvrtko.ursulin@intel.com 2020-03-12T11:57:48+00:00 07bcfd1291de77ffa9b627b4442783aba1335229 Allow super long OpenCL workloads which cannot be preempted within the default timeout to run out of the box. v2: * Make it stick out more and apply only to RCS. (Chris) v3: * Mention platform override in kconfig. (Joonas) Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Michal Mrozek <michal.mrozek@intel.com> Cc: <stable@vger.kernel.org> # v5.6+ Acked-by: Chris Wilson <chris@chris-wilson.co.uk> Acked-by: Michal Mrozek <Michal.mrozek@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200312115748.29970-1-tvrtko.ursulin@linux.intel.com 
Allow super long OpenCL workloads which cannot be preempted within
the default timeout to run out of the box.

v2:
 * Make it stick out more and apply only to RCS. (Chris)

v3:
 * Mention platform override in kconfig. (Joonas)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michal Mrozek <michal.mrozek@intel.com>
Cc: <stable@vger.kernel.org> # v5.6+
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Michal Mrozek <Michal.mrozek@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200312115748.29970-1-tvrtko.ursulin@linux.intel.com
drm/i915/gt: Expose heartbeat interval via sysfs 2020-02-28T22:03:49+00:00 Chris Wilson chris@chris-wilson.co.uk 2020-02-28T13:17:16+00:00 9a40bddd47ca4aa26d3b10bdaf51c35862a344ff We monitor the health of the system via periodic heartbeat pulses. The pulses also provide the opportunity to perform garbage collection. However, we interpret an incomplete pulse (a missed heartbeat) as an indication that the system is no longer responsive, i.e. hung, and perform an engine or full GPU reset. Given that the preemption granularity can be very coarse on a system, we let the sysadmin override our legacy timeouts which were "optimised" for desktop applications. The heartbeat interval can be adjusted per-engine using, /sys/class/drm/card?/engine/*/heartbeat_interval_ms Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Steve Carbonari <steven.carbonari@intel.com> Tested-by: Steve Carbonari <steven.carbonari@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-7-chris@chris-wilson.co.uk 
We monitor the health of the system via periodic heartbeat pulses. The
pulses also provide the opportunity to perform garbage collection.
However, we interpret an incomplete pulse (a missed heartbeat) as an
indication that the system is no longer responsive, i.e. hung, and
perform an engine or full GPU reset. Given that the preemption
granularity can be very coarse on a system, we let the sysadmin override
our legacy timeouts which were "optimised" for desktop applications.

The heartbeat interval can be adjusted per-engine using,

	/sys/class/drm/card?/engine/*/heartbeat_interval_ms

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Steve Carbonari <steven.carbonari@intel.com>
Tested-by: Steve Carbonari <steven.carbonari@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-7-chris@chris-wilson.co.uk
drm/i915/gt: Expose preempt reset timeout via sysfs 2020-02-28T22:03:46+00:00 Chris Wilson chris@chris-wilson.co.uk 2020-02-28T13:17:15+00:00 db3d8338bacbfc734d246eaccfbe5b19ad81d7d4 After initialising a preemption request, we give the current resident a small amount of time to vacate the GPU. The preemption request is for a higher priority context and should be immediate to maintain high quality of service (and avoid priority inversion). However, the preemption granularity of the GPU can be quite coarse and so we need a compromise. The preempt timeout can be adjusted per-engine using, /sys/class/drm/card?/engine/*/preempt_timeout_ms and can be disabled by setting it to 0. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Steve Carbonari <steven.carbonari@intel.com> Tested-by: Steve Carbonari <steven.carbonari@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-6-chris@chris-wilson.co.uk 
After initialising a preemption request, we give the current resident a
small amount of time to vacate the GPU. The preemption request is for a
higher priority context and should be immediate to maintain high
quality of service (and avoid priority inversion). However, the
preemption granularity of the GPU can be quite coarse and so we need a
compromise.

The preempt timeout can be adjusted per-engine using,

	/sys/class/drm/card?/engine/*/preempt_timeout_ms

and can be disabled by setting it to 0.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Steve Carbonari <steven.carbonari@intel.com>
Tested-by: Steve Carbonari <steven.carbonari@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-6-chris@chris-wilson.co.uk
drm/i915/gt: Expose reset stop timeout via sysfs 2020-02-28T22:03:43+00:00 Chris Wilson chris@chris-wilson.co.uk 2020-02-28T13:17:14+00:00 72338a1f5ef8a480184aac48bcc8e9f7d4d0d0a5 When we allow ourselves to sleep before a GPU reset after disabling submission, even for a few milliseconds, gives an innocent context the opportunity to clear the GPU before the reset occurs. However, how long to sleep depends on the typical non-preemptible duration (a similar problem to determining the ideal preempt-reset timeout or even the heartbeat interval). As this seems of a hard policy decision, punt it to userspace. The timeout can be adjusted using /sys/class/drm/card?/engine/*/stop_timeout_ms Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Jon Bloomfield <jon.bloomfield@intel.com> Reviewed-by: Steve Carbonari <steven.carbonari@intel.com> Tested-by: Steve Carbonari <steven.carbonari@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-5-chris@chris-wilson.co.uk 
When we allow ourselves to sleep before a GPU reset after disabling
submission, even for a few milliseconds, gives an innocent context the
opportunity to clear the GPU before the reset occurs. However, how long
to sleep depends on the typical non-preemptible duration (a similar
problem to determining the ideal preempt-reset timeout or even the
heartbeat interval). As this seems of a hard policy decision, punt it to
userspace.

The timeout can be adjusted using

	/sys/class/drm/card?/engine/*/stop_timeout_ms

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Steve Carbonari <steven.carbonari@intel.com>
Tested-by: Steve Carbonari <steven.carbonari@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-5-chris@chris-wilson.co.uk
drm/i915/gt: Expose busywait duration to sysfs 2020-02-28T22:03:41+00:00 Chris Wilson chris@chris-wilson.co.uk 2020-02-28T13:17:13+00:00 062444bbc6859dbe9991673ffd377a4af4d76d51 We busywait on an inflight request (one that is currently executing on HW, and so might complete quickly) prior to setting up an interrupt and sleeping. The trade off is that we keep an expensive CPU core busy in order to avoid wake up latency: where that trade off should lie is best left to the sysadmin. The busywait mechanism can be compiled out with ./scripts/config --set-val DRM_I915_SPIN_REQUEST 0 The maximum busywait duration can be adjusted per-engine using, /sys/class/drm/card?/engine/*/ms_busywait_duration_ns Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Steve Carbonari <steven.carbonari@intel.com> Tested-by: Steve Carbonari <steven.carbonari@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-4-chris@chris-wilson.co.uk 
We busywait on an inflight request (one that is currently executing on
HW, and so might complete quickly) prior to setting up an interrupt and
sleeping. The trade off is that we keep an expensive CPU core busy in
order to avoid wake up latency: where that trade off should lie is best
left to the sysadmin.

The busywait mechanism can be compiled out with

	./scripts/config --set-val DRM_I915_SPIN_REQUEST 0

The maximum busywait duration can be adjusted per-engine using,

	/sys/class/drm/card?/engine/*/ms_busywait_duration_ns

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Steve Carbonari <steven.carbonari@intel.com>
Tested-by: Steve Carbonari <steven.carbonari@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-4-chris@chris-wilson.co.uk
drm/i915/gt: Expose timeslice duration to sysfs 2020-02-28T22:03:39+00:00 Chris Wilson chris@chris-wilson.co.uk 2020-02-28T13:17:12+00:00 1a2695a7465971f28d8c44d6a282b6a2dd91e96f Execlists uses a scheduling quantum (a timeslice) to alternate execution between ready-to-run contexts of equal priority. This ensures that all users (though only if they of equal importance) have the opportunity to run and prevents livelocks where contexts may have implicit ordering due to userspace semaphores. The timeslicing mechanism can be compiled out with ./scripts/config --set-val DRM_I915_TIMESLICE_DURATION 0 The timeslice duration can be adjusted per-engine using, /sys/class/drm/card?/engine/*/timeslice_duration_ms Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Steve Carbonari <steven.carbonari@intel.com> Tested-by: Steve Carbonari <steven.carbonari@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-3-chris@chris-wilson.co.uk 
Execlists uses a scheduling quantum (a timeslice) to alternate execution
between ready-to-run contexts of equal priority. This ensures that all
users (though only if they of equal importance) have the opportunity to
run and prevents livelocks where contexts may have implicit ordering due
to userspace semaphores.

The timeslicing mechanism can be compiled out with

	./scripts/config --set-val DRM_I915_TIMESLICE_DURATION 0

The timeslice duration can be adjusted per-engine using,

	/sys/class/drm/card?/engine/*/timeslice_duration_ms

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Steve Carbonari <steven.carbonari@intel.com>
Tested-by: Steve Carbonari <steven.carbonari@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-3-chris@chris-wilson.co.uk
drm/i915: Default to a more lenient forced preemption timeout 2019-11-26T09:38:44+00:00 Chris Wilson chris@chris-wilson.co.uk 2019-11-25T16:27:37+00:00 5766a5ffc6a69595903865518c43636bde0e4ac4 Based on a sampling of a number of benchmarks across platforms, by default opt for a much more lenient timeout so that we should not adversely affect existing "good" clients. 640ms ought to be enough for anyone. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112169 Fixes: 3a7a92aba8fb ("drm/i915/execlists: Force preemption") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Eero Tamminen <eero.t.tamminen@intel.com> Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191125162737.2161069-1-chris@chris-wilson.co.uk 
Based on a sampling of a number of benchmarks across platforms, by
default opt for a much more lenient timeout so that we should not
adversely affect existing "good" clients.

640ms ought to be enough for anyone.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112169
Fixes: 3a7a92aba8fb ("drm/i915/execlists: Force preemption")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191125162737.2161069-1-chris@chris-wilson.co.uk