- 06 3月, 2019 1 次提交
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由 Chris Wilson 提交于
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: NChris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20190305213830.18094-1-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
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- 02 3月, 2019 3 次提交
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由 Chris Wilson 提交于
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: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190301170901.8340-4-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
Having introduced per-context seqno, we now have a means to identity progress across the system without feel of rollback as befell the global_seqno. That is we can program a MI_SEMAPHORE_WAIT operation in advance of submission safe in the knowledge that our target seqno and address is stable. However, since we are telling the GPU to busy-spin on the target address until it matches the signaling seqno, we only want to do so when we are sure that busy-spin will be completed quickly. To achieve this we only submit the request to HW once the signaler is itself executing (modulo preemption causing us to wait longer), and we only do so for default and above priority requests (so that idle priority tasks never themselves hog the GPU waiting for others). As might be reasonably expected, HW semaphores excel in inter-engine synchronisation microbenchmarks (where the 3x reduced latency / increased throughput more than offset the power cost of spinning on a second ring) and have significant improvement (can be up to ~10%, most see no change) for single clients that utilize multiple engines (typically media players and transcoders), without regressing multiple clients that can saturate the system or changing the power envelope dramatically. v3: Drop the older NEQ branch, now we pin the signaler's HWSP anyway. v4: Tell the world and include it as part of scheduler caps. Testcase: igt/gem_exec_whisper Testcase: igt/benchmarks/gem_wsim Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190301170901.8340-3-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
In preparation for enabling HW semaphores, we need to keep in flight timeline HWSP alive until its use across entire system has completed, as any other timeline active on the GPU may still refer back to the already retired timeline. We both have to delay recycling available cachelines and unpinning old HWSP until the next idle point. An easy option would be to simply keep all used HWSP until the system as a whole was idle, i.e. we could release them all at once on parking. However, on a busy system, we may never see a global idle point, essentially meaning the resource will be leaked until we are forced to do a GC pass. We already employ a fine-grained idle detection mechanism for vma, which we can reuse here so that each cacheline can be freed immediately after the last request using it is retired. v3: Keep track of the activity of each cacheline. v4: cacheline_free() on canceling the seqno tracking v5: Finally with a testcase to exercise wraparound v6: Pack cacheline into empty bits of page-aligned vaddr v7: Use i915_utils to hide the pointer casting around bit manipulation Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190301170901.8340-2-chris@chris-wilson.co.uk
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- 01 3月, 2019 2 次提交
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由 Chris Wilson 提交于
A simple mutex used for guarding the flow of requests in and out of the timeline. In the short-term, it will be used only to guard the addition of requests into the timeline, taken on alloc and released on commit so that only one caller can construct a request into the timeline (important as the seqno and ring pointers must be serialised). This will be used by observers to ensure that the seqno/hwsp is stable. Later, when we have reduced retiring to only operate on a single timeline at a time, we can then use the mutex as the sole guard required for retiring. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190301110547.14758-2-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
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: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NTvrtko 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
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- 28 2月, 2019 1 次提交
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由 Chris Wilson 提交于
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: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190228102035.5857-1-chris@chris-wilson.co.uk
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- 26 2月, 2019 2 次提交
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由 Chris Wilson 提交于
Having weaned the interrupt handling off using a single global execution queue, we no longer need to emit a global_seqno. Note that we still have a few assumptions about execution order along engine timelines, but this removes the most obvious artefact! Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190226094922.31617-3-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
Stop accessing the HWSP to read the global seqno, and stop tracking the mirror in the engine's execution timeline -- it is unused. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190226094922.31617-2-chris@chris-wilson.co.uk
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- 21 2月, 2019 1 次提交
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由 Chris Wilson 提交于
At a few points in our uABI, we check to see if the driver is wedged and report -EIO back to the user in that case. However, as we perform the check and reset asynchronously (where once before they were both serialised by the struct_mutex), we may instead see the temporary wedging used to cancel inflight rendering to avoid a deadlock during reset (caused by either us timing out in our reset handler, i915_wedge_on_timeout or with malice aforethought in intel_reset_prepare for a stuck modeset). If we suspect this is the case, that is we see a wedged driver *and* reset in progress, then wait until the reset is resolved before reporting upon the wedged status. v2: might_sleep() (Mika) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109580Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190220145637.23503-1-chris@chris-wilson.co.uk
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- 19 2月, 2019 1 次提交
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由 Chris Wilson 提交于
Currently, we accumulate each time a context hangs the GPU, offset against the number of requests it submits, and if that score exceeds a certain threshold, we ban that context from submitting any more requests (cancelling any work in flight). In contrast, we use a simple timer on the file, that if we see more than a 9 hangs faster than 60s apart in total across all of its contexts, we will ban the client from creating any more contexts. This leads to a confusing situation where the file may be banned before the context, so lets use a simple timer scheme for each. If the context submits 3 hanging requests within a 120s period, declare it forbidden to ever send more requests. This has the advantage of not being easy to repair by simply sending empty requests, but has the disadvantage that if the context is idle then it is forgiven. However, if the context is idle, it is not disrupting the system, but a hog can evade the request counting and cause much more severe disruption to the system. Updating ban_score from request retirement is dubious as the retirement is purposely not in sync with request submission (i.e. we try and batch retirement to reduce overhead and avoid latency on submission), which leads to surprising situations where we can forgive a hang immediately due to a backlog of requests from before the hang being retired afterwards. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190219122215.8941-2-chris@chris-wilson.co.uk
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- 15 2月, 2019 1 次提交
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由 Chris Wilson 提交于
As we currently do not check on submission whether the context is banned in a timely manner it is possible for some requests to escape cancellation after their parent context is banned. By moving the ban into the request submission under the engine->timeline.lock, we serialise it with the reset and setting of the context ban. References: eb8d0f5a ("drm/i915: Remove GPU reset dependence on struct_mutex") Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190213182737.12695-1-chris@chris-wilson.co.ukReviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
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- 13 2月, 2019 1 次提交
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由 Chris Wilson 提交于
As time goes by, usage of generic ioctls such as drm_syncobj and sync_file are on the increase bypassing i915-specific ioctls like GEM_WAIT. Currently, we only apply waitboosting to our driver ioctls as we track the file/client and account the waitboosting to them. However, since commit 7b92c1bd ("drm/i915: Avoid keeping waitboost active for signaling threads"), we no longer have been applying the client ratelimiting on waitboosts and so that information has only been used for debug tracking. Push the application of waitboosting down to the common i915_request_wait, and apply it to all foreign fence waits as well. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Eero Tamminen <eero.t.tamminen@intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190213092504.25709-1-chris@chris-wilson.co.uk
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- 06 2月, 2019 1 次提交
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由 Chris Wilson 提交于
Looking forward, we need to break the struct_mutex dependency on i915_gem_active. In the meantime, external use of i915_gem_active is quite beguiling, little do new users suspect that it implies a barrier as each request it tracks must be ordered wrt the previous one. As one of many, it can be used to track activity across multiple timelines, a shared fence, which fits our unordered request submission much better. We need to steer external users away from the singular, exclusive fence imposed by i915_gem_active to i915_active instead. As part of that process, we move i915_gem_active out of i915_request.c into i915_active.c to start separating the two concepts, and rename it to i915_active_request (both to tie it to the concept of tracking just one request, and to give it a longer, less appealing name). Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190205130005.2807-5-chris@chris-wilson.co.uk
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- 05 2月, 2019 2 次提交
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由 Tvrtko Ursulin 提交于
Timeline barrier allows serialization between different timelines. After calling i915_timeline_set_barrier with a request, all following submissions on this timeline will be set up as depending on this request, or barrier. Once the barrier has been completed it automatically gets cleared and things continue as normal. This facility will be used by the upcoming context SSEU code. v2: * Assert barrier has been retired on timeline_fini. (Chris Wilson) * Fix mock_timeline. v3: * Improved comment language. (Chris Wilson) v4: * Maintain ordering with previous barriers set on the timeline. v5: * Rebase. Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Suggested-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20190205095032.22673-3-tvrtko.ursulin@linux.intel.com
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由 Chris Wilson 提交于
Limit the NEWCLIENT boost to only give its small priority boost to fresh clients only that have no dependencies. The idea for using NEWCLIENT boosting, commit b16c7651 ("drm/i915: Priority boost for new clients"), is that short-lived streams are often interactive and require lower latency -- and that by executing those ahead of the long running hogs, the short-lived clients do little to interfere with the system throughput by virtue of their short-lived nature. However, we were only considering the client's own timeline for determining whether or not it was a fresh stream. This allowed for compositors to wake up before their vblank and bump all of its client streams. However, in testing with media-bench this results in chaining all cooperating contexts together preventing us from being able to reorder contexts to reduce bubbles (pipeline stalls), overall increasing latency, and reducing system throughput. The exact opposite of our intent. The compromise of applying the NEWCLIENT boost to strictly fresh clients (that do not wait upon anything else) should maintain the "real-time response under load" characteristics of FQ_CODEL, without locking together the long chains of dependencies across the system. References: b16c7651 ("drm/i915: Priority boost for new clients") Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190204150101.30759-1-chris@chris-wilson.co.uk
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- 30 1月, 2019 2 次提交
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由 Chris Wilson 提交于
A few years ago, see commit 688e6c72 ("drm/i915: Slaughter the thundering i915_wait_request herd"), the issue of handling multiple clients waiting in parallel was brought to our attention. The requirement was that every client should be woken immediately upon its request being signaled, without incurring any cpu overhead. To handle certain fragility of our hw meant that we could not do a simple check inside the irq handler (some generations required almost unbounded delays before we could be sure of seqno coherency) and so request completion checking required delegation. Before commit 688e6c72, the solution was simple. Every client waiting on a request would be woken on every interrupt and each would do a heavyweight check to see if their request was complete. Commit 688e6c72 introduced an rbtree so that only the earliest waiter on the global timeline would woken, and would wake the next and so on. (Along with various complications to handle requests being reordered along the global timeline, and also a requirement for kthread to provide a delegate for fence signaling that had no process context.) The global rbtree depends on knowing the execution timeline (and global seqno). Without knowing that order, we must instead check all contexts queued to the HW to see which may have advanced. We trim that list by only checking queued contexts that are being waited on, but still we keep a list of all active contexts and their active signalers that we inspect from inside the irq handler. By moving the waiters onto the fence signal list, we can combine the client wakeup with the dma_fence signaling (a dramatic reduction in complexity, but does require the HW being coherent, the seqno must be visible from the cpu before the interrupt is raised - we keep a timer backup just in case). Having previously fixed all the issues with irq-seqno serialisation (by inserting delays onto the GPU after each request instead of random delays on the CPU after each interrupt), we can rely on the seqno state to perfom direct wakeups from the interrupt handler. This allows us to preserve our single context switch behaviour of the current routine, with the only downside that we lose the RT priority sorting of wakeups. In general, direct wakeup latency of multiple clients is about the same (about 10% better in most cases) with a reduction in total CPU time spent in the waiter (about 20-50% depending on gen). Average herd behaviour is improved, but at the cost of not delegating wakeups on task_prio. v2: Capture fence signaling state for error state and add comments to warm even the most cold of hearts. v3: Check if the request is still active before busywaiting v4: Reduce the amount of pointer misdirection with list_for_each_safe and using a local i915_request variable inside the loops v5: Add a missing pluralisation to a purely informative selftest message. References: 688e6c72 ("drm/i915: Slaughter the thundering i915_wait_request herd") Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190129205230.19056-2-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
To allow requests to forgo a common execution timeline, one question we need to be able to answer is "is this request running?". To track whether a request has started on HW, we can emit a breadcrumb at the beginning of the request and check its timeline's HWSP to see if the breadcrumb has advanced past the start of this request. (This is in contrast to the global timeline where we need only ask if we are on the global timeline and if the timeline has advanced past the end of the previous request.) There is still confusion from a preempted request, which has already started but relinquished the HW to a high priority request. For the common case, this discrepancy should be negligible. However, for identification of hung requests, knowing which one was running at the time of the hang will be much more important. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190129185452.20989-2-chris@chris-wilson.co.uk
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- 29 1月, 2019 2 次提交
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由 Chris Wilson 提交于
Now that we have allocated ourselves a cacheline to store a breadcrumb, we can emit a write from the GPU into the timeline's HWSP of the per-context seqno as we complete each request. This drops the mirroring of the per-engine HWSP and allows each context to operate independently. We do not need to unwind the per-context timeline, and so requests are always consistent with the timeline breadcrumb, greatly simplifying the completion checks as we no longer need to be concerned about the global_seqno changing mid check. One complication though is that we have to be wary that the request may outlive the HWSP and so avoid touching the potentially danging pointer after we have retired the fence. We also have to guard our access of the HWSP with RCU, the release of the obj->mm.pages should already be RCU-safe. At this point, we are emitting both per-context and global seqno and still using the single per-engine execution timeline for resolving interrupts. v2: s/fake_complete/mark_complete/ Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190128181812.22804-5-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
Supplement the per-engine HWSP with a per-timeline HWSP. That is a per-request pointer through which we can check a local seqno, abstracting away the presumption of a global seqno. In this first step, we point each request back into the engine's HWSP so everything continues to work with the global timeline. v2: s/i915_request_hwsp/hwsp_seqno/ to emphasis that this is the current HW value and that we are accessing it via i915_request merely as a convenience. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NJohn Harrison <John.C.Harrison@Intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190128181812.22804-1-chris@chris-wilson.co.uk
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- 25 1月, 2019 2 次提交
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由 Chris Wilson 提交于
Now that the submission backends are controlled via their own spinlocks, with a wave of a magic wand we can lift the struct_mutex requirement around GPU reset. That is we allow the submission frontend (userspace) to keep on submitting while we process the GPU reset as we can suspend the backend independently. The major change is around the backoff/handoff strategy for performing the reset. With no mutex deadlock, we no longer have to coordinate with any waiter, and just perform the reset immediately. Testcase: igt/gem_mmap_gtt/hang # regresses Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190125132230.22221-3-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
Now that we know we measure the size of the engine->emit_breadcrumb() correctly, we can remove the previous manual counting. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190125120005.25191-1-chris@chris-wilson.co.uk
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- 22 1月, 2019 1 次提交
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由 Chris Wilson 提交于
A repeated pattern is to test the signaled bit of our request->fence.flags. Make this an inline to shorten a few lines and remove unnecessary line continuations. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190121222117.23305-20-chris@chris-wilson.co.uk
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- 21 1月, 2019 1 次提交
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由 Chris Wilson 提交于
We are not allowed to assign rq->global_seqno=0 as it has a special meaning of "inactive" (not executing on HW). Fixes: 6faf5916 ("drm/i915: Remove HW semaphores for gen7 inter-engine synchronisation") Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190119143024.26971-1-chris@chris-wilson.co.uk
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- 17 1月, 2019 1 次提交
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由 Chris Wilson 提交于
Currently the code to reset the GPU and our state is spread widely across a few files. Pull the logic together into a common file. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Acked-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190116153304.787-1-chris@chris-wilson.co.uk
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- 10 1月, 2019 1 次提交
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由 Chris Wilson 提交于
In the continual quest to reduce the amount of global work required when submitting requests, replace i915_retire_requests() after allocation failure to retiring just our ring. v2: Don't forget the list iteration included an early break, so we would never throttle on the last request in the ring/timeline. v3: Use the common ring_retire_requests() References: 11abf0c5 ("drm/i915: Limit the backpressure for i915_request allocation") Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190109215932.26454-1-chris@chris-wilson.co.uk
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- 31 12月, 2018 2 次提交
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由 Chris Wilson 提交于
Now that we have eliminated the CPU-side irq_seqno_barrier by moving the delays on the GPU before emitting the MI_USER_INTERRUPT, we can remove the engine->irq_seqno_barrier infrastructure. Though intentionally slowing down the GPU is nasty, so is the code we can now remove! Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181228171641.16531-6-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
Now that we perform the request flushing inline with emitting the breadcrumb, we can remove the now redundant manual flush. And we can also remove the infrastructure that remained only for its purpose. v2: emit_breadcrumb_sz is in dwords, but rq->reserved_space is in bytes Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181228171641.16531-1-chris@chris-wilson.co.uk
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- 28 12月, 2018 1 次提交
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由 Chris Wilson 提交于
The writing is on the wall for the existence of a single execution queue along each engine, and as a consequence we will not be able to track dependencies along the HW queue itself, i.e. we will not be able to use HW semaphores on gen7 as they use a global set of registers (and unlike gen8+ we can not effectively target memory to keep per-context seqno and dependencies). On the positive side, when we implement request reordering for gen7 we also can not presume a simple execution queue and would also require removing the current semaphore generation code. So this bring us another step closer to request reordering for ringbuffer submission! The negative side is that using interrupts to drive inter-engine synchronisation is much slower (4us -> 15us to do a nop on each of the 3 engines on ivb). This is much better than it was at the time of introducing the HW semaphores and equally important userspace weaned itself off intermixing dependent BLT/RENDER operations (the prime culprit was glyph rendering in UXA). So while we regress the microbenchmarks, it should not impact the user. References: https://bugs.freedesktop.org/show_bug.cgi?id=108888Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181228140736.32606-2-chris@chris-wilson.co.uk
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- 07 12月, 2018 2 次提交
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由 Mika Kuoppala 提交于
Many errs of the form: drivers/gpu/drm/i915/selftests/intel_hangcheck.c: In function ‘__igt_reset_evict_vma’: ./include/linux/kern_levels.h:5:18: error: format ‘%x’ expects argument of type ‘unsigned int’, but argum Fixes: b312d8ca ("dma-buf: make fence sequence numbers 64 bit v2") Cc: Christian König <christian.koenig@amd.com> Cc: Chunming Zhou <david1.zhou@amd.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk> Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20181207123428.16257-1-mika.kuoppala@linux.intel.com
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由 Chris Wilson 提交于
Move the common engine->emit_flush(EMIT_INVALIDATE) back to the backends (where it was once previously) as we seek to specialise it in future patches. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181207090213.14352-1-chris@chris-wilson.co.uk
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- 27 11月, 2018 1 次提交
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由 Chris Wilson 提交于
If the engine's seqno is already at our target seqno (most likely it hasn't been used since the last reset), we can skip serialising the engine and leave it as is. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181126095610.20962-1-chris@chris-wilson.co.uk
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- 26 10月, 2018 1 次提交
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由 Chris Wilson 提交于
A danger encountered when resetting the seqno (using debugfs/i915_next_seqno) is that as we change the breadcrumb stored in the HWSP, it may be inspected by the signaler thread leading to confusion in our sanity checks. <0> [136.331342] i915/sig-347 3..s1 136336154us : execlists_submission_tasklet: rcs0 awake?=1, active=5 <0> [136.331373] i915/sig-347 3d.s2 136336155us : process_csb: rcs0 cs-irq head=5, tail=0 <0> [136.331402] i915/sig-347 3d.s2 136336155us : process_csb: rcs0 csb[0]: status=0x00000018:0x00000002, active=0x5 <0> [136.331434] i915/sig-347 3d.s2 136336156us : process_csb: rcs0 out[0]: ctx=2.1, global=219 (fence 46:8455) (current 219), prio=0 <0> [136.331466] i915/sig-347 3d.s2 136336156us : process_csb: rcs0 completed ctx=2 <0> [136.332027] gem_exec-1049 0.... 136336246us : reset_all_global_seqno.part.5: rcs0 seqno 219 (current 219) -> -43 <0> [136.332056] gem_exec-1049 0.... 136336251us : reset_all_global_seqno.part.5: bcs0 seqno 183 (current 183) -> -43 <0> [136.332085] gem_exec-1049 0.... 136336255us : reset_all_global_seqno.part.5: vcs0 seqno 191 (current 191) -> -43 <0> [136.332114] gem_exec-1049 0.... 136336259us : reset_all_global_seqno.part.5: vcs1 seqno 180 (current 180) -> -43 <0> [136.332143] gem_exec-1049 0.... 136336262us : reset_all_global_seqno.part.5: vecs0 seqno 212 (current 212) -> -43 <0> [136.332174] i915/sig-347 3.... 136336280us : intel_breadcrumbs_signaler: intel_breadcrumbs_signaler:673 GEM_BUG_ON(!i915_request_completed(rq)) Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181024104939.2861-1-chris@chris-wilson.co.uk
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- 05 10月, 2018 1 次提交
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由 Chris Wilson 提交于
Earlier, we reasoned that having idled the gpu under mempressure, that would be a good time to trim our request slabs in order to perform the next request allocation. We have stopped performing the global operation on the device (no idling) and wish to make the allocation failure handling more local, so out with the global barrier that may take a long time. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181005080300.9908-2-chris@chris-wilson.co.uk
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- 02 10月, 2018 3 次提交
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由 Chris Wilson 提交于
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: NChris 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: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181001144755.7978-3-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
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: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181001144755.7978-2-chris@chris-wilson.co.uk
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由 Chris Wilson 提交于
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: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181001144755.7978-1-chris@chris-wilson.co.uk
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- 14 9月, 2018 1 次提交
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由 Chris Wilson 提交于
If we try and fail to allocate a i915_request, we apply some backpressure on the clients to throttle the memory allocations coming from i915.ko. Currently, we wait until completely idle, but this is far too heavy and leads to some situations where the only escape is to declare a client hung and reset the GPU. The intent is to only ratelimit the allocation requests and to allow ourselves to recycle requests and memory from any long queues built up by a client hog. Although the system memory is inherently a global resources, we don't want to overly penalize an unlucky client to pay the price of reaping a hog. To reduce the influence of one client on another, we can instead of waiting for the entire GPU to idle, impose a barrier on the local client. (One end goal for request allocation is for scalability to many concurrent allocators; simultaneous execbufs.) To prevent ourselves from getting caught out by long running requests (requests that may never finish without userspace intervention, whom we are blocking) we need to impose a finite timeout, ideally shorter than hangcheck. A long time ago Paul McKenney suggested that RCU users should ratelimit themselves using judicious use of cond_synchronize_rcu(). This gives us the opportunity to reduce our indefinite wait for the GPU to idle to a wait for the RCU grace period of the previous allocation along this timeline to expire, satisfying both the local and finite properties we desire for our ratelimiting. There are still a few global steps (reclaim not least amongst those!) when we exhaust the immediate slab pool, at least now the wait is itself decoupled from struct_mutex for our glorious highly parallel future! Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106680Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180914080017.30308-1-chris@chris-wilson.co.uk
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- 07 8月, 2018 1 次提交
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由 Chris Wilson 提交于
We have a few instances of checking seqno-1 to see if the HW has started the request. Pull those together under a helper. v2: Pull the !seqno assertion higher, as given seqno==1 we may indeed check to see if we have started using seqno==0. Suggested-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180806112605.20725-1-chris@chris-wilson.co.uk
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- 09 7月, 2018 1 次提交
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由 Chris Wilson 提交于
Usually we have no idea about the upper bound we need to wait to catch up with userspace when idling the device, but in a few situations we know the system was idle beforehand and can provide a short timeout in order to very quickly catch a failure, long before hangcheck kicks in. In the following patches, we will use the timeout to curtain two overly long waits, where we know we can expect the GPU to complete within a reasonable time or declare it broken. In particular, with a broken GPU we expect it to fail during the initial GPU setup where do a couple of context switches to record the defaults. This is a task that takes a few milliseconds even on the slowest of devices, but we may have to wait 60s for hangcheck to give in and declare the machine inoperable. In this a case where any gpu hang is unacceptable, both from a timeliness and practical standpoint. The other improvement is that in selftests, we do not need to arm an independent timer to inject a wedge, as we can just limit the timeout on the wait directly. v2: Include the timeout parameter in the trace. Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180709122044.7028-1-chris@chris-wilson.co.uk
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