On 26/11/2019 04:51, Ankit Navik wrote:
High resolution timer is used for predictive governor to control
eu/slice/subslice based on workloads.
param is provided to enable/disable/update timer configuration
V2:
* Fix code style.
* Move predictive_load_timer into a drm_i915_private
structure.
* Make generic function to set optimum config. (Tvrtko Ursulin)
V3:
* Rebase.
* Fix race condition for predictive load set.
* Add slack to start hrtimer for more power efficient. (Tvrtko Ursulin)
V4:
* Fix data type and initialization of mutex to protect predictive load
state.
* Move predictive timer init to i915_gem_init_early. (Tvrtko Ursulin)
* Move debugfs to kernel parameter.
V5:
* Rebase.
* Remove mutex for pred_timer
V6:
* Rebase.
* Fix warnings.
Cc: Vipin Anand <vipin.anand@xxxxxxxxx>
Signed-off-by: Ankit Navik <ankit.p.navik@xxxxxxxxx>
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/gt/intel_deu.c | 104 ++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/gt/intel_deu.h | 31 +++++++++++
drivers/gpu/drm/i915/i915_drv.h | 4 ++
drivers/gpu/drm/i915/i915_gem.c | 4 ++
drivers/gpu/drm/i915/i915_params.c | 4 ++
drivers/gpu/drm/i915/i915_params.h | 1 +
7 files changed, 149 insertions(+)
create mode 100644 drivers/gpu/drm/i915/gt/intel_deu.c
create mode 100644 drivers/gpu/drm/i915/gt/intel_deu.h
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index e0fd10c..c1a98f3 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -77,6 +77,7 @@ obj-y += gt/
gt-y += \
gt/intel_breadcrumbs.o \
gt/intel_context.o \
+ gt/intel_deu.o \
gt/intel_engine_cs.o \
gt/intel_engine_heartbeat.o \
gt/intel_engine_pm.o \
diff --git a/drivers/gpu/drm/i915/gt/intel_deu.c b/drivers/gpu/drm/i915/gt/intel_deu.c
new file mode 100644
index 0000000..6c5b01c
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_deu.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ * Ankit Navik <ankit.p.navik@xxxxxxxxx>
+ */
+
+/**
+ * DOC: Dynamic EU Control (DEU)
+ *
+ * DEU tries to re-configure EU allocation during runtime by predictive load
+ * calculation of command queue to gain power saving.
+ * It is transparent to user space and completely handled in the kernel.
+ */
+
+#include "intel_deu.h"
+#include "i915_drv.h"
+#include "gem/i915_gem_context.h"
+
+/*
+ * Anything above threshold is considered as HIGH load, less is considered
+ * as LOW load and equal is considered as MEDIUM load.
+ *
+ * The threshold value of three active requests pending.
+ */
+#define PENDING_THRESHOLD_MEDIUM 3
+
+#define SLACK_TIMER_NSEC 1000000 /* Timer range in nano second */
+
+enum hrtimer_restart predictive_load_cb(struct hrtimer *hrtimer)
+{
+ struct drm_i915_private *dev_priv =
+ container_of(hrtimer, typeof(*dev_priv), pred_timer);
+ struct i915_gem_context *ctx;
+ enum gem_load_type load_type;
+ unsigned int req_pending;
+
+ list_for_each_entry(ctx, &dev_priv->gem.contexts.list, link) {
+ req_pending = atomic_read(&ctx->req_cnt);
+
+ /*
+ * Transitioning to low state whenever pending request is zero
+ * would cause vacillation between low and high state.
+ */
+ if (req_pending == 0)
+ continue;
+
+ if (req_pending > PENDING_THRESHOLD_MEDIUM)
+ load_type = LOAD_TYPE_HIGH;
+ else if (req_pending == PENDING_THRESHOLD_MEDIUM)
+ load_type = LOAD_TYPE_MEDIUM;
+ else
+ load_type = LOAD_TYPE_LOW;
+
+ i915_gem_context_set_load_type(ctx, load_type);
+ }
Now ideally we don't want to iterate contexts from a timer for more than
one reason. Most interesting one is that the configuration you are
setting here is not actually applied until __execlists_update_reg_state.
Which runs only when contexts is getting pinned (or re-pinned).
You mentioned you did some experiment where you did something on context
pinning and that it did not work so well. I don't know what that was
though. I don't think that was ever posted?
What I am thinking is this: You drop the timer altogether. Instead in
__execlists_update_reg_state you look at your gem_context->req_cnt and
implement your logic there.
You convert your selected configuration to struct intel_sseu (so counts
to bitmasks) and pass it to intel_sseu_make_rpcs which does the right thing.
+
+ hrtimer_forward_now(hrtimer,
+ ms_to_ktime(dev_priv->predictive_load_enable));
+
+ return HRTIMER_RESTART;
+}
+
+/**
+ * intel_deu_init - Initialize dynamic EU
+ * @dev_priv: i915 device instance
+ *
+ * This function is called at driver load
+ */
+void intel_deu_init(struct drm_i915_private *dev_priv)
+{
+ dev_priv->predictive_load_enable = i915_modparams.deu_enable;
+ hrtimer_init(&dev_priv->pred_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ dev_priv->pred_timer.function = predictive_load_cb;
+
+ if (dev_priv->predictive_load_enable) {
+ if (!hrtimer_active(&dev_priv->pred_timer))
+ hrtimer_start_range_ns(&dev_priv->pred_timer,
+ ms_to_ktime(dev_priv->predictive_load_enable),
+ SLACK_TIMER_NSEC,
+ HRTIMER_MODE_REL_PINNED);
+ } else {
+ hrtimer_cancel(&dev_priv->pred_timer);
Why do you need to stop something which hasn't been started?
And more importantly, who stops the timer on driver unload?
+ }
+}
diff --git a/drivers/gpu/drm/i915/gt/intel_deu.h b/drivers/gpu/drm/i915/gt/intel_deu.h
new file mode 100644
index 0000000..3b4b16f
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_deu.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef __INTEL_DEU_H__
+#define __INTEL_DEU_H__
+
+struct drm_i915_private;
+
+void intel_deu_init(struct drm_i915_private *dev_priv);
+
+#endif /* __INTEL_DEU_H__ */
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3064ddf..5553537 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1002,6 +1002,8 @@ struct drm_i915_private {
/* optimal slice/subslice/EU configration state */
struct i915_sseu_optimum_config *opt_config;
+ /* protects predictive load state */
+ struct hrtimer pred_timer;
int predictive_load_enable;
unsigned int fsb_freq, mem_freq, is_ddr3;
@@ -1768,6 +1770,8 @@ long i915_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
#endif
extern const struct dev_pm_ops i915_pm_ops;
+extern enum hrtimer_restart predictive_load_cb(struct hrtimer *hrtimer);
+
int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent);
void i915_driver_remove(struct drm_i915_private *i915);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 61395b0..ee711ce 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -45,6 +45,7 @@
#include "gem/i915_gem_context.h"
#include "gem/i915_gem_ioctls.h"
#include "gem/i915_gem_pm.h"
+#include "gt/intel_deu.h"
#include "gt/intel_context.h"
#include "gt/intel_engine_user.h"
#include "gt/intel_gt.h"
@@ -1416,6 +1417,9 @@ void i915_gem_init_early(struct drm_i915_private *dev_priv)
i915_gem_init__mm(dev_priv);
spin_lock_init(&dev_priv->fb_tracking.lock);
+
+ /* Dynamic EU timer initialization for predictive load */
+ intel_deu_init(dev_priv);
}
void i915_gem_cleanup_early(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 1dd1f36..a5a3a6e 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -101,6 +101,10 @@ i915_param_named_unsafe(disable_power_well, int, 0400,
i915_param_named_unsafe(enable_ips, int, 0600, "Enable IPS (default: true)");
+i915_param_named_unsafe(deu_enable, int, 0600,
+ "Enable dynamic EU control for power savings "
+ "(0=disable deu predictive timer [default], 150=optimal deu predictive timer)"); > +
i915_param_named(fastboot, int, 0600,
"Try to skip unnecessary mode sets at boot time "
"(0=disabled, 1=enabled) "
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 31b88f2..cf0903b 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -54,6 +54,7 @@ struct drm_printer;
param(int, disable_power_well, -1) \
param(int, enable_ips, 1) \
param(int, invert_brightness, 0) \
+ param(int, deu_enable, 0) \
param(int, enable_guc, 0) \
param(int, guc_log_level, -1) \
param(char *, guc_firmware_path, NULL) \
Regards,
Tvrtko
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