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path: root/drivers/gpu/drm/i915/i915_scheduler.h
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2019-04-02drm/i915: Move intel_engine_mask_t around for use by i915_request_types.hChris Wilson1-84/+2
We want to use intel_engine_mask_t inside i915_request.h, which means extracting it from the general header file mess and placing it inside a types.h. A knock on effect is that the compiler wants to warn about type-contraction of ALL_ENGINES into intel_engine_maskt_t, so prepare for the worst. v2: Use intel_engine_mask_t consistently v3: Move I915_NUM_ENGINES to its natural home at the end of the enum Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: John Harrison <John.C.Harrison@Intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190401162641.10963-1-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
2019-03-06drm/i915: Use i915_global_register()Chris Wilson1-4/+0
Rather than manually add every new global into each hook, use i915_global_register() function and keep a list of registered globals to invoke instead. However, I haven't found a way for random drivers to add an .init table to avoid having to manually add ourselves to i915_globals_init() each time. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20190305213830.18094-1-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
2019-03-01drm/i915: Prioritise non-busywait semaphore workloadsChris Wilson1-3/+6
We don't want to busywait on the GPU if we have other work to do. If we give non-busywaiting workloads higher (initial) priority than workloads that require a busywait, we will prioritise work that is ready to run immediately. We then also have to be careful that we don't give earlier semaphores an accidental boost because later work doesn't wait on other rings, hence we keep a history of semaphore usage of the dependency chain. v2: Stop rolling the bits into a chain and just use a flag in case this request or any of our dependencies use a semaphore. The rolling around was contagious as Tvrtko was heard to fall off his chair. Testcase: igt/gem_exec_schedule/semaphore Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190301170901.8340-4-chris@chris-wilson.co.uk
2019-03-01drm/i915/execlists: Suppress mere WAIT preemptionChris Wilson1-0/+2
WAIT is occasionally suppressed by virtue of preempted requests being promoted to NEWCLIENT if they have not all ready received that boost. Make this consistent for all WAIT boosts that they are not allowed to preempt executing contexts and are merely granted the right to be at the front of the queue for the next execution slot. This is in keeping with the desire that the WAIT boost be a minor tweak that does not give excessive promotion to its user and open ourselves to trivial abuse. The problem with the inconsistent WAIT preemption becomes more apparent as the preemption is propagated across the engines, where one engine may preempt and the other not, and we be relying on the exact execution order being consistent across engines (e.g. using HW semaphores to coordinate parallel execution). v2: Also protect GuC submission from false preemption loops. v3: Build bug safeguards and better debug messages for st. v4: Do the priority bumping in unsubmit (i.e. on preemption/reset unwind), applying it earlier during submit causes out-of-order execution combined with execute fences. v5: Call sw_fence_fini for our dummy request (Matthew) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190228220639.3173-1-chris@chris-wilson.co.uk
2019-02-28drm/i915: Use __ffs() in for_each_priolist for more compact codeChris Wilson1-2/+4
Gcc has a slight preference if we use __ffs() to subtract one from the index once rather than each use: __execlists_submission_tasklet 2867 2847 -20 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190226102404.29153-11-chris@chris-wilson.co.uk
2019-02-28drm/i915: Make request allocation caches globalChris Wilson1-4/+30
As kmem_caches share the same properties (size, allocation/free behaviour) for all potential devices, we can use global caches. While this potential has worse fragmentation behaviour (one can argue that different devices would have different activity lifetimes, but you can also argue that activity is temporal across the system) it is the default behaviour of the system at large to amalgamate matching caches. The benefit for us is much reduced pointer dancing along the frequent allocation paths. v2: Defer shrinking until after a global grace period for futureproofing multiple consumers of the slab caches, similar to the current strategy for avoiding shrinking too early. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190228102035.5857-1-chris@chris-wilson.co.uk
2018-10-01drm/i915: Priority boost for waiting clientsChris Wilson1-2/+5
Latency is in the eye of the beholder. In the case where a client stops and waits for the gpu, give that request chain a small priority boost (not so that it overtakes higher priority clients, to preserve the external ordering) so that ideally the wait completes earlier. v2: Tvrtko recommends to keep the boost-from-user-stall as small as possible and to allow new client flows to be preferred for interactivity over stalls. Testcase: igt/gem_sync/switch-default Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.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/20181001144755.7978-3-chris@chris-wilson.co.uk
2018-10-01drm/i915: Pull scheduling under standalone lockChris Wilson1-0/+25
Currently, the backend scheduling code abuses struct_mutex into order to have a global lock to manipulate a temporary list (without widespread allocation) and to protect against list modifications. This is an extraneous coupling to struct_mutex and further can not extend beyond the local device. Pull all the code that needs to be under the one true lock into i915_scheduler.c, and make it so. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181001144755.7978-2-chris@chris-wilson.co.uk
2018-10-01drm/i915: Priority boost for new clientsChris Wilson1-1/+3
Taken from an idea used for FQ_CODEL, we give the first request of a new request flows a small priority boost. These flows are likely to correspond with short, interactive tasks and so be more latency sensitive than the longer free running queues. As soon as the client has more than one request in the queue, further requests are not boosted and it settles down into ordinary steady state behaviour. Such small kicks dramatically help combat the starvation issue, by allowing each client the opportunity to run even when the system is under heavy throughput load (within the constraints of the user selected priority). v2: Mark the preempted request as the start of a new flow, to prevent a single client being continually gazumped by its peers. Testcase: igt/benchmarks/rrul Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181001144755.7978-1-chris@chris-wilson.co.uk
2018-10-01drm/i915: Reserve some priority bits for internal useChris Wilson1-0/+6
In the next few patches, we will want to give a small priority boost to some requests/queues but not so much that we perturb the user controlled order. As such we will shift the user priority bits higher leaving ourselves a few low priority bits for our internal bumping. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181001123204.23982-3-chris@chris-wilson.co.uk
2018-04-18drm/i915: Pack params to engine->schedule() into a structChris Wilson1-1/+16
Today we only want to pass along the priority to engine->schedule(), but in the future we want to have much more control over the various aspects of the GPU during a context's execution, for example controlling the frequency allowed. As we need an ever growing number of parameters for scheduling, move those into a struct for convenience. v2: Move the anonymous struct into its own function for legibility and ye olde gcc. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180418184052.7129-3-chris@chris-wilson.co.uk
2018-04-18drm/i915: Rename priotree to schedChris Wilson1-2/+2
Having moved the priotree struct into i915_scheduler.h, identify it as the scheduling element and rebrand into i915_sched. This becomes more useful as we start attaching more information we require to propagate through the scheduler. v2: Use i915_sched_node for future distinctiveness Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180418184052.7129-2-chris@chris-wilson.co.uk
2018-04-18drm/i915: Move the priotree struct to its own headersChris Wilson1-0/+57
Over time the priotree has grown from a sorted list to a more complicated structure for propagating constraints along the dependency chain to try and resolve priority inversion. Start to segregate this information from the rest of the request/fence tracking. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180418184052.7129-1-chris@chris-wilson.co.uk