[Intel-gfx] [CI 1/2] drm/i915/gt: Schedule request retirement when signaler idles

[Intel-gfx] [CI 1/2] drm/i915/gt: Schedule request retirement when signaler idles

[Chris Wilson]

Very similar to commit 4f88f8747fa4 ("drm/i915/gt: Schedule request
retirement when timeline idles"), but this time instead of coupling into
the execlists CS event interrupt, we couple into the breadcrumb
interrupt and queue a timeline's retirement when the last signaler is
completed. This should allow us to more rapidly park ringbuffer
submission, and so help reduce power consumption on older systems.

v2: Fixup intel_engine_add_retire() to handle concurrent callers

References: 4f88f8747fa4 ("drm/i915/gt: Schedule request retirement when timeline idles")
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>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 6 +++++-
 drivers/gpu/drm/i915/gt/intel_gt_requests.c | 7 ++-----
 drivers/gpu/drm/i915/gt/intel_lrc.c         | 2 +-
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index 5fa4d621528e..4f491791b4ba 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -29,6 +29,7 @@
 #include "i915_drv.h"
 #include "i915_trace.h"
 #include "intel_gt_pm.h"
+#include "intel_gt_requests.h"
 
 static void irq_enable(struct intel_engine_cs *engine)
 {
@@ -179,8 +180,11 @@ static void signal_irq_work(struct irq_work *work)
 		if (!list_is_first(pos, &ce->signals)) {
 			/* Advance the list to the first incomplete request */
 			__list_del_many(&ce->signals, pos);
-			if (&ce->signals == pos) /* now empty */
+			if (&ce->signals == pos) { /* now empty */
 				list_del_init(&ce->signal_link);
+				intel_engine_add_retire(ce->engine,
+							ce->timeline);
+			}
 		}
 	}
 
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
index 8cb5421e5f0e..0d1bca787288 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
@@ -62,19 +62,16 @@ static void engine_retire(struct work_struct *work)
 static bool add_retire(struct intel_engine_cs *engine,
 		       struct intel_timeline *tl)
 {
+#define STUB ((struct intel_timeline *)1)
 	struct intel_timeline *first;
 
 	/*
 	 * We open-code a llist here to include the additional tag [BIT(0)]
 	 * so that we know when the timeline is already on a
 	 * retirement queue: either this engine or another.
-	 *
-	 * However, we rely on that a timeline can only be active on a single
-	 * engine at any one time and that add_retire() is called before the
-	 * engine releases the timeline and transferred to another to retire.
 	 */
 
-	if (READ_ONCE(tl->retire)) /* already queued */
+	if (cmpxchg(&tl->retire, NULL, STUB)) /* already queued */
 		return false;
 
 	intel_timeline_get(tl);
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 4db54fd6a2fe..56cf71d8bbda 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -4511,8 +4511,8 @@ intel_execlists_create_virtual(struct i915_gem_context *ctx,
 
 	intel_engine_init_active(&ve->base, ENGINE_VIRTUAL);
 	intel_engine_init_breadcrumbs(&ve->base);
-
 	intel_engine_init_execlists(&ve->base);
+	intel_engine_init_retire(&ve->base);
 
 	ve->base.cops = &virtual_context_ops;
 	ve->base.request_alloc = execlists_request_alloc;
-- 
2.24.1

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[Intel-gfx] [CI 2/2] drm/i915/gt: Track engine round-trip times

[Chris Wilson]

Knowing the round trip time of an engine is useful for tracking the
health of the system as well as providing a metric for the baseline
responsiveness of the engine. We can use the latter metric for
automatically tuning our waits in selftests and when idling so we don't
confuse a slower system with a dead one.

Upon idling the engine, we send one last pulse to switch the context
away from precious user state to the volatile kernel context. We know
the engine is idle at this point, and the pulse is non-preemptible, so
this provides us with a good measurement of the round trip time. It also
provides us with faster engine parking for ringbuffer submission, which
is a welcome bonus (e.g. softer-rc6).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191219105043.4169050-1-chris@chris-wilson.co.uk
---
 drivers/gpu/drm/i915/gt/intel_engine_cs.c    |  3 +++
 drivers/gpu/drm/i915/gt/intel_engine_pm.c    | 22 +++++++++++++++++++-
 drivers/gpu/drm/i915/gt/intel_engine_types.h | 11 ++++++++++
 drivers/gpu/drm/i915/i915_request.h          |  4 ++++
 4 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 3d1d48bf90cf..6dd18f93d45c 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -334,6 +334,7 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id)
 	/* Nothing to do here, execute in order of dependencies */
 	engine->schedule = NULL;
 
+	ewma__engine_latency_init(&engine->latency);
 	seqlock_init(&engine->stats.lock);
 
 	ATOMIC_INIT_NOTIFIER_HEAD(&engine->context_status_notifier);
@@ -1481,6 +1482,8 @@ void intel_engine_dump(struct intel_engine_cs *engine,
 	drm_printf(m, "\tAwake? %d\n", atomic_read(&engine->wakeref.count));
 	drm_printf(m, "\tBarriers?: %s\n",
 		   yesno(!llist_empty(&engine->barrier_tasks)));
+	drm_printf(m, "\tLatency: %luus\n",
+		   ewma__engine_latency_read(&engine->latency));
 
 	rcu_read_lock();
 	rq = READ_ONCE(engine->heartbeat.systole);
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index bcbda8e52d41..8fb7b34fc5a6 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -73,6 +73,15 @@ static inline void __timeline_mark_unlock(struct intel_context *ce,
 
 #endif /* !IS_ENABLED(CONFIG_LOCKDEP) */
 
+static void duration(struct dma_fence *fence, struct dma_fence_cb *cb)
+{
+	struct i915_request *rq = to_request(fence);
+
+	ewma__engine_latency_add(&rq->engine->latency,
+				 ktime_us_delta(rq->fence.timestamp,
+						rq->duration.emitted));
+}
+
 static void
 __queue_and_release_pm(struct i915_request *rq,
 		       struct intel_timeline *tl,
@@ -163,7 +172,18 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
 
 	/* Install ourselves as a preemption barrier */
 	rq->sched.attr.priority = I915_PRIORITY_BARRIER;
-	__i915_request_commit(rq);
+	if (likely(!__i915_request_commit(rq))) { /* engine should be idle! */
+		/*
+		 * Use an interrupt for precise measurement of duration,
+		 * otherwise we rely on someone else retiring all the requests
+		 * which may delay the signaling (i.e. we will likely wait
+		 * until the background request retirement running every
+		 * second or two).
+		 */
+		BUILD_BUG_ON(sizeof(rq->duration) > sizeof(rq->submitq));
+		dma_fence_add_callback(&rq->fence, &rq->duration.cb, duration);
+		rq->duration.emitted = ktime_get();
+	}
 
 	/* Expose ourselves to the world */
 	__queue_and_release_pm(rq, ce->timeline, engine);
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 17f1f1441efc..7f227da09d66 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -7,6 +7,7 @@
 #ifndef __INTEL_ENGINE_TYPES__
 #define __INTEL_ENGINE_TYPES__
 
+#include <linux/average.h>
 #include <linux/hashtable.h>
 #include <linux/irq_work.h>
 #include <linux/kref.h>
@@ -119,6 +120,9 @@ enum intel_engine_id {
 #define INVALID_ENGINE ((enum intel_engine_id)-1)
 };
 
+/* A simple estimator for the round-trip latency of an engine */
+DECLARE_EWMA(_engine_latency, 6, 4)
+
 struct st_preempt_hang {
 	struct completion completion;
 	unsigned int count;
@@ -316,6 +320,13 @@ struct intel_engine_cs {
 		struct intel_timeline *timeline;
 	} legacy;
 
+	/*
+	 * We track the average duration of the idle pulse on parking the
+	 * engine to keep an estimate of the how the fast the engine is
+	 * under ideal conditions.
+	 */
+	struct ewma__engine_latency latency;
+
 	/* Rather than have every client wait upon all user interrupts,
 	 * with the herd waking after every interrupt and each doing the
 	 * heavyweight seqno dance, we delegate the task (of being the
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index aa38290eea3d..c18c0bcd0193 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -150,6 +150,10 @@ struct i915_request {
 	union {
 		wait_queue_entry_t submitq;
 		struct i915_sw_dma_fence_cb dmaq;
+		struct i915_request_duration_cb {
+			struct dma_fence_cb cb;
+			ktime_t emitted;
+		} duration;
 	};
 	struct list_head execute_cb;
 	struct i915_sw_fence semaphore;
-- 
2.24.1

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[Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [CI,1/2] drm/i915/gt: Schedule request retirement when signaler idles

[Patchwork]

== Series Details ==

Series: series starting with [CI,1/2] drm/i915/gt: Schedule request retirement when signaler idles
URL   : https://patchwork.freedesktop.org/series/71172/
State : warning

== Summary ==

$ dim checkpatch origin/drm-tip
c1298d970af7 drm/i915/gt: Schedule request retirement when signaler idles
-:15: WARNING:COMMIT_LOG_LONG_LINE: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#15: 
References: 4f88f8747fa4 ("drm/i915/gt: Schedule request retirement when timeline idles")

-:15: ERROR:GIT_COMMIT_ID: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'commit 4f88f8747fa4 ("drm/i915/gt: Schedule request retirement when timeline idles")'
#15: 
References: 4f88f8747fa4 ("drm/i915/gt: Schedule request retirement when timeline idles")

total: 1 errors, 1 warnings, 0 checks, 49 lines checked
ef9d1ed3a21e drm/i915/gt: Track engine round-trip times

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[Intel-gfx] ✗ Fi.CI.BAT: failure for series starting with [CI,1/2] drm/i915/gt: Schedule request retirement when signaler idles

[Patchwork]

== Series Details ==

Series: series starting with [CI,1/2] drm/i915/gt: Schedule request retirement when signaler idles
URL   : https://patchwork.freedesktop.org/series/71172/
State : failure

== Summary ==

CI Bug Log - changes from CI_DRM_7607 -> Patchwork_15842
====================================================

Summary
-------

  **FAILURE**

  Serious unknown changes coming with Patchwork_15842 absolutely need to be
  verified manually.
  
  If you think the reported changes have nothing to do with the changes
  introduced in Patchwork_15842, please notify your bug team to allow them
  to document this new failure mode, which will reduce false positives in CI.

  External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/index.html

Possible new issues
-------------------

  Here are the unknown changes that may have been introduced in Patchwork_15842:

### IGT changes ###

#### Possible regressions ####

  * igt@gem_exec_basic@basic-all:
    - fi-byt-j1900:       [PASS][1] -> [FAIL][2]
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-byt-j1900/igt@gem_exec_basic@basic-all.html
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-byt-j1900/igt@gem_exec_basic@basic-all.html

  
Known issues
------------

  Here are the changes found in Patchwork_15842 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@i915_selftest@live_gem_contexts:
    - fi-byt-j1900:       [PASS][3] -> [INCOMPLETE][4] ([i915#45])
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-byt-j1900/igt@i915_selftest@live_gem_contexts.html
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-byt-j1900/igt@i915_selftest@live_gem_contexts.html

  
#### Possible fixes ####

  * igt@i915_module_load@reload-with-fault-injection:
    - fi-kbl-guc:         [INCOMPLETE][5] ([i915#671]) -> [PASS][6]
   [5]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-kbl-guc/igt@i915_module_load@reload-with-fault-injection.html
   [6]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-kbl-guc/igt@i915_module_load@reload-with-fault-injection.html

  * igt@i915_pm_rpm@module-reload:
    - fi-skl-6770hq:      [FAIL][7] ([i915#178]) -> [PASS][8]
   [7]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-skl-6770hq/igt@i915_pm_rpm@module-reload.html
   [8]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-skl-6770hq/igt@i915_pm_rpm@module-reload.html

  * igt@i915_selftest@live_blt:
    - fi-ivb-3770:        [DMESG-FAIL][9] ([i915#725]) -> [PASS][10]
   [9]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-ivb-3770/igt@i915_selftest@live_blt.html
   [10]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-ivb-3770/igt@i915_selftest@live_blt.html

  * igt@i915_selftest@live_gem_contexts:
    - fi-hsw-peppy:       [INCOMPLETE][11] ([i915#694]) -> [PASS][12]
   [11]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-hsw-peppy/igt@i915_selftest@live_gem_contexts.html
   [12]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-hsw-peppy/igt@i915_selftest@live_gem_contexts.html

  * igt@kms_frontbuffer_tracking@basic:
    - fi-hsw-peppy:       [DMESG-WARN][13] ([i915#44]) -> [PASS][14]
   [13]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-hsw-peppy/igt@kms_frontbuffer_tracking@basic.html
   [14]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-hsw-peppy/igt@kms_frontbuffer_tracking@basic.html

  
#### Warnings ####

  * igt@i915_pm_rpm@basic-pci-d3-state:
    - fi-kbl-x1275:       [DMESG-WARN][15] ([i915#62] / [i915#92]) -> [DMESG-WARN][16] ([i915#62] / [i915#92] / [i915#95]) +6 similar issues
   [15]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-kbl-x1275/igt@i915_pm_rpm@basic-pci-d3-state.html
   [16]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-kbl-x1275/igt@i915_pm_rpm@basic-pci-d3-state.html

  * igt@i915_selftest@live_blt:
    - fi-hsw-4770:        [DMESG-FAIL][17] ([i915#725]) -> [DMESG-FAIL][18] ([i915#553] / [i915#725])
   [17]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-hsw-4770/igt@i915_selftest@live_blt.html
   [18]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-hsw-4770/igt@i915_selftest@live_blt.html

  * igt@kms_pipe_crc_basic@suspend-read-crc-pipe-a:
    - fi-kbl-x1275:       [DMESG-WARN][19] ([i915#62] / [i915#92] / [i915#95]) -> [DMESG-WARN][20] ([i915#62] / [i915#92]) +4 similar issues
   [19]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7607/fi-kbl-x1275/igt@kms_pipe_crc_basic@suspend-read-crc-pipe-a.html
   [20]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/fi-kbl-x1275/igt@kms_pipe_crc_basic@suspend-read-crc-pipe-a.html

  
  {name}: This element is suppressed. This means it is ignored when computing
          the status of the difference (SUCCESS, WARNING, or FAILURE).

  [fdo#111593]: https://bugs.freedesktop.org/show_bug.cgi?id=111593
  [i915#178]: https://gitlab.freedesktop.org/drm/intel/issues/178
  [i915#44]: https://gitlab.freedesktop.org/drm/intel/issues/44
  [i915#45]: https://gitlab.freedesktop.org/drm/intel/issues/45
  [i915#553]: https://gitlab.freedesktop.org/drm/intel/issues/553
  [i915#62]: https://gitlab.freedesktop.org/drm/intel/issues/62
  [i915#671]: https://gitlab.freedesktop.org/drm/intel/issues/671
  [i915#694]: https://gitlab.freedesktop.org/drm/intel/issues/694
  [i915#725]: https://gitlab.freedesktop.org/drm/intel/issues/725
  [i915#92]: https://gitlab.freedesktop.org/drm/intel/issues/92
  [i915#95]: https://gitlab.freedesktop.org/drm/intel/issues/95


Participating hosts (49 -> 43)
------------------------------

  Additional (1): fi-hsw-4770r 
  Missing    (7): fi-ilk-m540 fi-hsw-4200u fi-byt-squawks fi-bsw-cyan fi-bdw-samus fi-byt-clapper fi-skl-6600u 


Build changes
-------------

  * CI: CI-20190529 -> None
  * Linux: CI_DRM_7607 -> Patchwork_15842

  CI-20190529: 20190529
  CI_DRM_7607: a5637870d1eaf736172c3444c02ebe5f7d2ad161 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_5351: e7fdcef72d1d6b3bb9f3003bbc37571959e6e8bb @ git://anongit.freedesktop.org/xorg/app/intel-gpu-tools
  Patchwork_15842: ef9d1ed3a21e18ffceed0f38ee5565f58dccbabb @ git://anongit.freedesktop.org/gfx-ci/linux


== Linux commits ==

ef9d1ed3a21e drm/i915/gt: Track engine round-trip times
c1298d970af7 drm/i915/gt: Schedule request retirement when signaler idles

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_15842/index.html
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Re: [Intel-gfx] [CI 2/2] drm/i915/gt: Track engine round-trip times

[youling257]

This patch cause GPU hang on my Bay trail z3735f.
https://gitlab.freedesktop.org/drm/intel/issues/1144
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Re: [Intel-gfx] [CI 2/2] drm/i915/gt: Track engine round-trip times

[Chris Wilson]

Quoting youling257 (2020-02-07 16:31:25)
> This patch cause GPU hang on my Bay trail z3735f.
> https://gitlab.freedesktop.org/drm/intel/issues/1144

No it didn't. The cause for that is unfortunately well known.
-Chris
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Re: [Intel-gfx] [CI 2/2] drm/i915/gt: Track engine round-trip times

[youling 257]

That's my build many times test boot result.
https://github.com/youling257/android-4.9/commits/drm-intel
the "drm/i915/gt: Track engine round-trip times" is bad commit for my
Androidx86.

2020-02-08 0:34 GMT+08:00, Chris Wilson <chris@chris-wilson.co.uk>:
> Quoting youling257 (2020-02-07 16:31:25)
>> This patch cause GPU hang on my Bay trail z3735f.
>> https://gitlab.freedesktop.org/drm/intel/issues/1144
>
> No it didn't. The cause for that is unfortunately well known.
> -Chris
>
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Re: [Intel-gfx] [CI 2/2] drm/i915/gt: Track engine round-trip times

[youling 257]

2020-02-08 0:34 GMT+08:00, Chris Wilson <chris@chris-wilson.co.uk>:
> Quoting youling257 (2020-02-07 16:31:25)
>> This patch cause GPU hang on my Bay trail z3735f.
>> https://gitlab.freedesktop.org/drm/intel/issues/1144
>
> No it didn't. The cause for that is unfortunately well known.
> -Chris
>
“drm/i915/gt: Track engine round-trip times” Make the gpu hang problem
worse, can't boot enter userspace at all.
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Re: [Intel-gfx] [CI 2/2] drm/i915/gt: Track engine round-trip times

[youling 257]

it's not the patch "Track engine round-trip times".

it's "drm/i915/gem: Asynchronous cmdparser" "drm/i915/gem: Prepare
gen7 cmdparser for async execution" bad for my Bay trail device.
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