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44505168 |
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16-Nov-2021 |
Matthew Brost <matthew.brost@intel.com> |
drm/i915: Drop stealing of bits from i915_sw_fence function pointer Rather than stealing bits from i915_sw_fence function pointer use separate fields for function pointer and flags. If using two different fields, the 4 byte alignment for the i915_sw_fence function pointer can also be dropped. v2: (CI) - Set new function field rather than flags in __i915_sw_fence_init v3: (Tvrtko) - Remove BUG_ON(!fence->flags) in reinit as that will now blow up - Only define fence->flags if CONFIG_DRM_I915_SW_FENCE_CHECK_DAG is defined v4: - Rebase, resend for CI Signed-off-by: Matthew Brost <matthew.brost@intel.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com> Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20211116194929.10211-1-matthew.brost@intel.com
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ef468849 |
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17-Aug-2019 |
Chris Wilson <chris@chris-wilson.co.uk> |
drm/i915: Propagate fence errors Errors spread like wildfire, and must eventually be returned to the user. They need to be captured and passed along the flow of fences, infecting each in turn with the existing error, until finally they fall out of a user visible result. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190817232511.11391-1-chris@chris-wilson.co.uk
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ee113690 |
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21-May-2019 |
Chris Wilson <chris@chris-wilson.co.uk> |
drm/i915/execlists: Virtual engine bonding Some users require that when a master batch is executed on one particular engine, a companion batch is run simultaneously on a specific slave engine. For this purpose, we introduce virtual engine bonding, allowing maps of master:slaves to be constructed to constrain which physical engines a virtual engine may select given a fence on a master engine. For the moment, we continue to ignore the issue of preemption deferring the master request for later. Ideally, we would like to then also remove the slave and run something else rather than have it stall the pipeline. With load balancing, we should be able to move workload around it, but there is a similar stall on the master pipeline while it may wait for the slave to be executed. At the cost of more latency for the bonded request, it may be interesting to launch both on their engines in lockstep. (Bubbles abound.) Opens: Also what about bonding an engine as its own master? It doesn't break anything internally, so allow the silliness. v2: Emancipate the bonds v3: Couple in delayed scheduling for the selftests v4: Handle invalid mutually exclusive bonding v5: Mention what the uapi does v6: s/nbond/num_bonds/ 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/20190521211134.16117-9-chris@chris-wilson.co.uk
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52c0fdb2 |
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29-Jan-2019 |
Chris Wilson <chris@chris-wilson.co.uk> |
drm/i915: Replace global breadcrumbs with per-context interrupt tracking A few years ago, see commit 688e6c725816 ("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 688e6c725816, 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 688e6c725816 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: 688e6c725816 ("drm/i915: Slaughter the thundering i915_wait_request herd") 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/20190129205230.19056-2-chris@chris-wilson.co.uk
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2ea5b4de |
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22-Oct-2017 |
Kees Cook <keescook@chromium.org> |
drm/i915/selftests: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Jani Nikula <jani.nikula@intel.com>
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02a1ca45 |
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25-Oct-2017 |
Chris Wilson <chris@chris-wilson.co.uk> |
Revert "drm/i915/selftests: Convert timers to use timer_setup()" This reverts commit 6d0dbd309687113009a276886628c7c74c848d3c. timer_setup_on_stack() does not yet exist: In file included from drivers/gpu/drm/i915/i915_sw_fence.c:517:0: drivers/gpu/drm/i915/selftests/lib_sw_fence.c: In function ‘timed_fence_init’: drivers/gpu/drm/i915/selftests/lib_sw_fence.c:63:2: error: implicit declaration of function ‘timer_setup_on_stack’; did you mean ‘hrtimer_init_on_stack’? [-Werror=implicit-function-declaration] timer_setup_on_stack(&tf->timer, timed_fence_wake, 0); Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20171025131336.2584-1-chris@chris-wilson.co.uk Acked-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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6d0dbd30 |
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24-Oct-2017 |
Kees Cook <keescook@chromium.org> |
drm/i915/selftests: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20171024151344.GA104417@beast Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
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214707fc |
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12-Oct-2017 |
Chris Wilson <chris@chris-wilson.co.uk> |
drm/i915/selftests: Wrap a timer into a i915_sw_fence For some selftests, we want to issue requests but delay them going to hardware. Furthermore, we don't want those requests to block indefinitely (or else we may hang the driver and block testing) so we want to employ a timeout. So naturally we want a fence that is automatically signaled by a timer. v2: Add kselftests. v3: Limit the API available to selftests; there isn't an overwhelming reason to export it universally. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20171012125726.14736-2-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
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