[PATCH 7/7] drm/i915: Deminish contribution of wait-boosting from clients

Chris Wilson
2015-03-06T15:06:39Z

With boosting for missed pageflips, we have a much stronger indication
of when we need to (temporarily) boost GPU frequency to ensure smooth
delivery of frames. So now only allow each client to perform one RPS boost
in each period of GPU activity due to stalling on results.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_debugfs.c | 39 +++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_drv.h | 9 ++++++---
drivers/gpu/drm/i915/i915_gem.c | 35 ++++++++-------------------------
drivers/gpu/drm/i915/intel_drv.h | 3 ++-
drivers/gpu/drm/i915/intel_pm.c | 18 ++++++++++++++---
5 files changed, 70 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index cc83cc0ff823..9366eaa50dba 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2245,6 +2245,44 @@ static int i915_ppgtt_info(struct seq_file *m, void *data)
return 0;
}

+static int i915_rps_boost_info(struct seq_file *m, void *data)
+{
+ struct drm_info_node *node = m->private;
+ struct drm_device *dev = node->minor->dev;
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct drm_file *file;
+ int ret;
+
+ ret = mutex_lock_interruptible(&dev->struct_mutex);
+ if (ret)
+ return ret;
+
+ ret = mutex_lock_interruptible(&dev_priv->rps.hw_lock);
+ if (ret)
+ goto unlock;
+
+ list_for_each_entry_reverse(file, &dev->filelist, lhead) {
+ struct drm_i915_file_private *file_priv = file->driver_priv;
+ struct task_struct *task;
+
+ rcu_read_lock();
+ task = pid_task(file->pid, PIDTYPE_PID);
+ seq_printf(m, "%s [%d]: %d boosts%s\n",
+ task ? task->comm : "<unknown>",
+ task ? task->pid : -1,
+ file_priv->rps_boosts,
+ list_empty(&file_priv->rps_boost) ? "" : ", active");
+ rcu_read_unlock();
+ }
+ seq_printf(m, "Kernel boosts: %d\n", dev_priv->rps.boosts);
+
+ mutex_unlock(&dev_priv->rps.hw_lock);
+unlock:
+ mutex_unlock(&dev->struct_mutex);
+
+ return ret;
+}
+
static int i915_llc(struct seq_file *m, void *data)
{
struct drm_info_node *node = m->private;
@@ -4680,6 +4718,7 @@ static const struct drm_info_list i915_debugfs_list[] = {
{"i915_ddb_info", i915_ddb_info, 0},
{"i915_sseu_status", i915_sseu_status, 0},
{"i915_drrs_status", i915_drrs_status, 0},
+ {"i915_rps_boost_info", i915_rps_boost_info, 0},
};
#define I915_DEBUGFS_ENTRIES ARRAY_SIZE(i915_debugfs_list)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index bfa6e11f802e..b207d2cec9dc 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1036,6 +1036,8 @@ struct intel_gen6_power_mgmt {

bool enabled;
struct delayed_work delayed_resume_work;
+ struct list_head clients;
+ unsigned boosts;

/* manual wa residency calculations */
struct intel_rps_ei up_ei, down_ei;
@@ -2137,12 +2139,13 @@ struct drm_i915_file_private {
struct {
spinlock_t lock;
struct list_head request_list;
- struct delayed_work idle_work;
} mm;
struct idr context_idr;

- atomic_t rps_wait_boost;
- struct intel_engine_cs *bsd_ring;
+ struct list_head rps_boost;
+ struct intel_engine_cs *bsd_ring;
+
+ unsigned rps_boosts;
};

/*
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index b266b31690e4..a0c35f80836c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1191,14 +1191,6 @@ static bool missed_irq(struct drm_i915_private *dev_priv,
return test_bit(ring->id, &dev_priv->gpu_error.missed_irq_rings);
}

-static bool can_wait_boost(struct drm_i915_file_private *file_priv)
-{
- if (file_priv == NULL)
- return true;
-
- return !atomic_xchg(&file_priv->rps_wait_boost, true);
-}
-
/**
* __i915_wait_request - wait until execution of request has finished
* @req: duh!
@@ -1240,13 +1232,8 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
timeout_expire = timeout ?
jiffies + nsecs_to_jiffies_timeout((u64)*timeout) : 0;

- if (INTEL_INFO(dev)->gen >= 6 && ring->id == RCS && can_wait_boost(file_priv)) {
- gen6_rps_boost(dev_priv);
- if (file_priv)
- mod_delayed_work(dev_priv->wq,
- &file_priv->mm.idle_work,
- msecs_to_jiffies(100));
- }
+ if (ring->id == RCS && INTEL_INFO(dev)->gen >= 6)
+ gen6_rps_boost(dev_priv, file_priv);

if (!irq_test_in_progress && WARN_ON(!ring->irq_get(ring)))
return -ENODEV;
@@ -5070,8 +5057,6 @@ void i915_gem_release(struct drm_device *dev, struct drm_file *file)
{
struct drm_i915_file_private *file_priv = file->driver_priv;

- cancel_delayed_work_sync(&file_priv->mm.idle_work);
-
/* Clean up our request list when the client is going away, so that
* later retire_requests won't dereference our soon-to-be-gone
* file_priv.
@@ -5087,15 +5072,12 @@ void i915_gem_release(struct drm_device *dev, struct drm_file *file)
request->file_priv = NULL;
}
spin_unlock(&file_priv->mm.lock);
-}
-
-static void
-i915_gem_file_idle_work_handler(struct work_struct *work)
-{
- struct drm_i915_file_private *file_priv =
- container_of(work, typeof(*file_priv), mm.idle_work.work);

- atomic_set(&file_priv->rps_wait_boost, false);
+ if (!list_empty(&file_priv->rps_boost)) {
+ mutex_lock(&to_i915(dev)->rps.hw_lock);
+ list_del(&file_priv->rps_boost);
+ mutex_unlock(&to_i915(dev)->rps.hw_lock);
+ }
}

int i915_gem_open(struct drm_device *dev, struct drm_file *file)
@@ -5112,11 +5094,10 @@ int i915_gem_open(struct drm_device *dev, struct drm_file *file)
file->driver_priv = file_priv;
file_priv->dev_priv = dev->dev_private;
file_priv->file = file;
+ INIT_LIST_HEAD(&file_priv->rps_boost);

spin_lock_init(&file_priv->mm.lock);
INIT_LIST_HEAD(&file_priv->mm.request_list);
- INIT_DELAYED_WORK(&file_priv->mm.idle_work,
- i915_gem_file_idle_work_handler);

ret = i915_gem_context_open(dev, file);
if (ret)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 87e09a58191a..299d0c68f0dd 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1241,7 +1241,8 @@ void gen6_update_ring_freq(struct drm_device *dev);
void gen6_rps_busy(struct drm_i915_private *dev_priv);
void gen6_rps_reset_ei(struct drm_i915_private *dev_priv);
void gen6_rps_idle(struct drm_i915_private *dev_priv);
-void gen6_rps_boost(struct drm_i915_private *dev_priv);
+void gen6_rps_boost(struct drm_i915_private *dev_priv,
+ struct drm_i915_file_private *file_priv);
void intel_queue_rps_boost_for_request(struct drm_device *dev,
struct drm_i915_gem_request *rq);
void ilk_wm_get_hw_state(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 120b8af3c60c..307edc035af1 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3931,10 +3931,14 @@ void gen6_rps_idle(struct drm_i915_private *dev_priv)
dev_priv->rps.last_adj = 0;
I915_WRITE(GEN6_PMINTRMSK, 0xffffffff);
}
+
+ while (!list_empty(&dev_priv->rps.clients))
+ list_del_init(dev_priv->rps.clients.next);
mutex_unlock(&dev_priv->rps.hw_lock);
}

-void gen6_rps_boost(struct drm_i915_private *dev_priv)
+void gen6_rps_boost(struct drm_i915_private *dev_priv,
+ struct drm_i915_file_private *file_priv)
{
u32 val;

@@ -3942,9 +3946,16 @@ void gen6_rps_boost(struct drm_i915_private *dev_priv)
val = dev_priv->rps.max_freq_softlimit;
if (dev_priv->rps.enabled &&
dev_priv->mm.busy &&
- dev_priv->rps.cur_freq < val) {
+ dev_priv->rps.cur_freq < val &&
+ (file_priv == NULL || list_empty(&file_priv->rps_boost))) {
intel_set_rps(dev_priv->dev, val);
dev_priv->rps.last_adj = 0;
+
+ if (file_priv != NULL) {
+ list_add(&file_priv->rps_boost, &dev_priv->rps.clients);
+ file_priv->rps_boosts++;
+ } else
+ dev_priv->rps.boosts++;
}
mutex_unlock(&dev_priv->rps.hw_lock);
}
@@ -6608,7 +6619,7 @@ static void __intel_rps_boost_work(struct work_struct *work)
struct request_boost *boost = container_of(work, struct request_boost, work);

if (!i915_gem_request_completed(boost->rq, true))
- gen6_rps_boost(to_i915(boost->rq->ring->dev));
+ gen6_rps_boost(to_i915(boost->rq->ring->dev), NULL);

i915_gem_request_unreference(boost->rq);
kfree(boost);
@@ -6640,6 +6651,7 @@ void intel_pm_setup(struct drm_device *dev)

INIT_DELAYED_WORK(&dev_priv->rps.delayed_resume_work,
intel_gen6_powersave_work);
+ INIT_LIST_HEAD(&dev_priv->rps.clients);

dev_priv->pm.suspended = false;
}
--
2.1.4