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linux (Generic): Replace waitboosting revert with Interactive RPS Mode fix

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MilhouseVH 2018-07-11 17:04:33 +01:00
parent 6b607ab2ec
commit 2a3c34d22e
2 changed files with 265 additions and 36 deletions
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265
packages/linux/patches/default/linux-999-drm_i915-interactive-rps-mode.patch Normal file
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@ -0,0 +1,265 @@
From 77a8e4fee1ad8cf7ec4a8899f76dfb9303b422f8 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 4 Jul 2018 08:45:48 +0100
Subject: [PATCH] drm/i915: Interactive RPS mode
RPS provides a feedback loop where we use the load during the previous
evaluation interval to decide whether to up or down clock the GPU
frequency. Our responsiveness is split into 3 regimes, a high and low
plateau with the intent to keep the gpu clocked high to cover occasional
stalls under high load, and low despite occasional glitches under steady
low load, and inbetween. However, we run into situations like kodi where
we want to stay at low power (video decoding is done efficiently
inside the fixed function HW and doesn't need high clocks even for high
bitrate streams), but just occasionally the pipeline is more complex
than a video decode and we need a smidgen of extra GPU power to present
on time. In the high power regime, we sample at sub frame intervals with
a bias to upclocking, and conversely at low power we sample over a few
frames worth to provide what we consider to be the right levels of
responsiveness respectively. At low power, we more or less expect to be
kicked out to high power at the start of a busy sequence by waitboosting.
Prior to commit e9af4ea2b9e7 ("drm/i915: Avoid waitboosting on the active
request") whenever we missed the frame or stalled, we would immediate go
full throttle and upclock the GPU to max. But in commit e9af4ea2b9e7, we
relaxed the waitboosting to only apply if the pipeline was deep to avoid
over-committing resources for a near miss. Sadly though, a near miss is
still a miss, and perceptible as jitter in the frame delivery.
To try and prevent the near miss before having to resort to boosting
after the fact, we use the pageflip queue as an indication that we are
in an "interactive" regime and so should sample the load more frequently
to provide power before the frame misses it vblank. This will make us
more favorable to providing a small power increase (one or two bins) as
required rather than going all the way to maximum and then having to
work back down again. (We still keep the waitboosting mechanism around
just in case a dramatic change in system load requires urgent uplocking,
faster than we can provide in a few evaluation intervals.)
References: https://bugs.freedesktop.org/show_bug.cgi?id=107111
References: e9af4ea2b9e7 ("drm/i915: Avoid waitboosting on the active request")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Radoslaw Szwichtenberg <radoslaw.szwichtenberg@intel.com>
---
drivers/gpu/drm/i915/i915_debugfs.c | 1 +
drivers/gpu/drm/i915/i915_drv.h | 6 +-
drivers/gpu/drm/i915/intel_display.c | 20 +++++++
drivers/gpu/drm/i915/intel_drv.h | 2 +
drivers/gpu/drm/i915/intel_pm.c | 87 ++++++++++++++++++----------
5 files changed, 86 insertions(+), 30 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 544e5e7f011f..7d974cad1cdf 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2218,6 +2218,7 @@ static int i915_rps_boost_info(struct seq_file *m, void *data)
seq_printf(m, "CPU waiting? %d\n", count_irq_waiters(dev_priv));
seq_printf(m, "Boosts outstanding? %d\n",
atomic_read(&rps->num_waiters));
+ seq_printf(m, "Power overrides? %d\n", READ_ONCE(rps->power_override));
seq_printf(m, "Frequency requested %d\n",
intel_gpu_freq(dev_priv, rps->cur_freq));
seq_printf(m, " min hard:%d, soft:%d; max soft:%d, hard:%d\n",
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 09ab12458244..3f9ae1095b98 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -783,7 +783,9 @@ struct intel_rps {
u8 down_threshold; /* Current %busy required to downclock */
int last_adj;
- enum { LOW_POWER, BETWEEN, HIGH_POWER } power;
+ enum { LOW_POWER, BETWEEN, HIGH_POWER, AUTO_POWER } power;
+ unsigned int power_override;
+ struct mutex power_lock;
bool enabled;
atomic_t num_waiters;
@@ -3429,6 +3431,8 @@ extern void i915_redisable_vga_power_on(struct drm_i915_private *dev_priv);
extern bool ironlake_set_drps(struct drm_i915_private *dev_priv, u8 val);
extern void intel_init_pch_refclk(struct drm_i915_private *dev_priv);
extern int intel_set_rps(struct drm_i915_private *dev_priv, u8 val);
+extern void intel_rps_set_power(struct drm_i915_private *dev_priv,
+ int new_power);
extern bool intel_set_memory_cxsr(struct drm_i915_private *dev_priv,
bool enable);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8f3199b06d1f..acedd9b2d54a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13104,6 +13104,19 @@ intel_prepare_plane_fb(struct drm_plane *plane,
add_rps_boost_after_vblank(new_state->crtc, new_state->fence);
}
+ /*
+ * We declare pageflips to be interactive and so merit a small bias
+ * towards upclocking to deliver the frame on time. By only changing
+ * the RPS thresholds to sample more regularly and aim for higher
+ * clocks we can hopefully deliver low power workloads (like kodi)
+ * that are not quite steady state without resorting to forcing
+ * maximum clocks following a vblank miss (see do_rps_boost()).
+ */
+ if (!intel_state->rps_override) {
+ intel_rps_set_power(dev_priv, HIGH_POWER);
+ intel_state->rps_override = true;
+ }
+
return 0;
}
@@ -13120,8 +13133,15 @@ void
intel_cleanup_plane_fb(struct drm_plane *plane,
struct drm_plane_state *old_state)
{
+ struct intel_atomic_state *intel_state =
+ to_intel_atomic_state(old_state->state);
struct drm_i915_private *dev_priv = to_i915(plane->dev);
+ if (intel_state->rps_override) {
+ intel_rps_set_power(dev_priv, AUTO_POWER);
+ intel_state->rps_override = false;
+ }
+
/* Should only be called after a successful intel_prepare_plane_fb()! */
mutex_lock(&dev_priv->drm.struct_mutex);
intel_plane_unpin_fb(to_intel_plane_state(old_state));
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 61e715ddd0d5..86685c43e1d2 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -482,6 +482,8 @@ struct intel_atomic_state {
*/
bool skip_intermediate_wm;
+ bool rps_override;
+
/* Gen9+ only */
struct skl_ddb_values wm_results;
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 53aaaa3e6886..0245a90d0fe5 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6264,41 +6264,14 @@ static u32 intel_rps_limits(struct drm_i915_private *dev_priv, u8 val)
return limits;
}
-static void gen6_set_rps_thresholds(struct drm_i915_private *dev_priv, u8 val)
+static void rps_set_power(struct drm_i915_private *dev_priv, int new_power)
{
struct intel_rps *rps = &dev_priv->gt_pm.rps;
- int new_power;
u32 threshold_up = 0, threshold_down = 0; /* in % */
u32 ei_up = 0, ei_down = 0;
- new_power = rps->power;
- switch (rps->power) {
- case LOW_POWER:
- if (val > rps->efficient_freq + 1 &&
- val > rps->cur_freq)
- new_power = BETWEEN;
- break;
-
- case BETWEEN:
- if (val <= rps->efficient_freq &&
- val < rps->cur_freq)
- new_power = LOW_POWER;
- else if (val >= rps->rp0_freq &&
- val > rps->cur_freq)
- new_power = HIGH_POWER;
- break;
+ lockdep_assert_held(&rps->power_lock);
- case HIGH_POWER:
- if (val < (rps->rp1_freq + rps->rp0_freq) >> 1 &&
- val < rps->cur_freq)
- new_power = BETWEEN;
- break;
- }
- /* Max/min bins are special */
- if (val <= rps->min_freq_softlimit)
- new_power = LOW_POWER;
- if (val >= rps->max_freq_softlimit)
- new_power = HIGH_POWER;
if (new_power == rps->power)
return;
@@ -6365,9 +6338,64 @@ static void gen6_set_rps_thresholds(struct drm_i915_private *dev_priv, u8 val)
rps->power = new_power;
rps->up_threshold = threshold_up;
rps->down_threshold = threshold_down;
+}
+
+static void gen6_set_rps_thresholds(struct drm_i915_private *dev_priv, u8 val)
+{
+ struct intel_rps *rps = &dev_priv->gt_pm.rps;
+ int new_power;
+
+ new_power = rps->power;
+ switch (rps->power) {
+ case AUTO_POWER:
+ case LOW_POWER:
+ if (val > rps->efficient_freq + 1 &&
+ val > rps->cur_freq)
+ new_power = BETWEEN;
+ break;
+
+ case BETWEEN:
+ if (val <= rps->efficient_freq &&
+ val < rps->cur_freq)
+ new_power = LOW_POWER;
+ else if (val >= rps->rp0_freq &&
+ val > rps->cur_freq)
+ new_power = HIGH_POWER;
+ break;
+
+ case HIGH_POWER:
+ if (val < (rps->rp1_freq + rps->rp0_freq) >> 1 &&
+ val < rps->cur_freq)
+ new_power = BETWEEN;
+ break;
+ }
+ /* Max/min bins are special */
+ if (val <= rps->min_freq_softlimit)
+ new_power = LOW_POWER;
+ if (val >= rps->max_freq_softlimit)
+ new_power = HIGH_POWER;
+
+ mutex_lock(&rps->power_lock);
+ if (!rps->power_override)
+ rps_set_power(dev_priv, new_power);
+ mutex_unlock(&rps->power_lock);
rps->last_adj = 0;
}
+void intel_rps_set_power(struct drm_i915_private *dev_priv, int power)
+{
+ struct intel_rps *rps = &dev_priv->gt_pm.rps;
+
+ mutex_lock(&rps->power_lock);
+ if (power != AUTO_POWER) {
+ rps->power_override++;
+ rps_set_power(dev_priv, power);
+ } else {
+ rps->power_override--;
+ }
+ mutex_unlock(&rps->power_lock);
+}
+
static u32 gen6_rps_pm_mask(struct drm_i915_private *dev_priv, u8 val)
{
struct intel_rps *rps = &dev_priv->gt_pm.rps;
@@ -9604,6 +9632,7 @@ int intel_freq_opcode(struct drm_i915_private *dev_priv, int val)
void intel_pm_setup(struct drm_i915_private *dev_priv)
{
mutex_init(&dev_priv->pcu_lock);
+ mutex_init(&dev_priv->gt_pm.rps.power_lock);
atomic_set(&dev_priv->gt_pm.rps.num_waiters, 0);
--
2.18.0

36
packages/linux/patches/default/linux-999-drm_i915-partial-revert-of-waitboosting-fix.patch
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@ -1,36 +0,0 @@
From 836bcce2ecdd9d6ea0650acc9da4f74239a8463b Mon Sep 17 00:00:00 2001
From: MilhouseVH <milhouseVH.github@nmacleod.com>
Date: Tue, 3 Jul 2018 06:17:27 +0100
Subject: [PATCH] drm/i915: partial revert of
e9af4ea2b9e7e5d3caa6354be14de06b678ed0fa
The original change leaves the GPU more or less permanently in low power mode
with the GPU running at idle frequency and never boosting which may result in
stutter in the Kodi GUI. Tested on Skylake NUC6i5SYH.
---
drivers/gpu/drm/i915/i915_request.h | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index eddbd424..3f2895a 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -298,14 +298,7 @@ static inline bool i915_request_completed(const struct i915_request *rq)
static inline bool i915_request_started(const struct i915_request *rq)
{
- u32 seqno;
-
- seqno = i915_request_global_seqno(rq);
- if (!seqno)
- return false;
-
- return i915_seqno_passed(intel_engine_get_seqno(rq->engine),
- seqno - 1);
+ return false;
}
static inline bool i915_sched_node_signaled(const struct i915_sched_node *node)
--
2.14.1