From: Rob Clark <robdclark@xxxxxxxxxxxx>
Minimize interactive latency by boosting frequency when userspace is
waiting on the GPU to finish.
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
I did contemplate also boosting on dma_fence_wait(), but (a) that would
require some extra plumbing thru gpu-sched, (b) that only captures a
sub-set of wait-on-dma-fence patterns, and (c) waiting on a dma-fence
doesn't always imply urgency (for ex, virglrenderer poll()ing on a dma-
fence to know when to send a fence irq to VM guest). But the driver
WAIT_FENCE and CPU_PREP ioctls map to things like glFinish() where it
is pretty clear that there is something wishing the GPU would finish
sooner.
drivers/gpu/drm/msm/msm_drv.c | 7 +++++--
drivers/gpu/drm/msm/msm_gem.c | 6 ++++++
drivers/gpu/drm/msm/msm_gpu_devfreq.c | 2 +-
3 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index c3b77b44b2aa..017a512982a2 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -894,7 +894,7 @@ static int msm_ioctl_gem_info(struct drm_device *dev, void *data,
}
static int wait_fence(struct msm_gpu_submitqueue *queue, uint32_t fence_id,
- ktime_t timeout)
+ ktime_t timeout, struct msm_gpu *gpu)
{
struct dma_fence *fence;
int ret;
@@ -924,6 +924,9 @@ static int wait_fence(struct msm_gpu_submitqueue *queue, uint32_t fence_id,
if (!fence)
return 0;
+ if (!dma_fence_is_signaled(fence))
+ msm_devfreq_boost(gpu, 2);
+
ret = dma_fence_wait_timeout(fence, true, timeout_to_jiffies(&timeout));
if (ret == 0) {
ret = -ETIMEDOUT;
@@ -956,7 +959,7 @@ static int msm_ioctl_wait_fence(struct drm_device *dev, void *data,
if (!queue)
return -ENOENT;
- ret = wait_fence(queue, args->fence, to_ktime(args->timeout));
+ ret = wait_fence(queue, args->fence, to_ktime(args->timeout), priv->gpu);
msm_submitqueue_put(queue);
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 1dee0d18abbb..fbda0e3a94f8 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -846,6 +846,12 @@ int msm_gem_cpu_prep(struct drm_gem_object *obj, uint32_t op, ktime_t *timeout)
op & MSM_PREP_NOSYNC ? 0 : timeout_to_jiffies(timeout);
long ret;
+ if (!dma_resv_test_signaled(obj->resv, dma_resv_usage_rw(write))) {
+ struct msm_drm_private *priv = obj->dev->dev_private;
+
+ msm_devfreq_boost(priv->gpu, 2);
+ }
+
ret = dma_resv_wait_timeout(obj->resv, dma_resv_usage_rw(write),
true, remain);
if (ret == 0)
diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c
index 85c443a37e4e..025940eb08d1 100644
--- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c
+++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c
@@ -305,7 +305,7 @@ void msm_devfreq_boost(struct msm_gpu *gpu, unsigned factor)
struct msm_gpu_devfreq *df = &gpu->devfreq;
uint64_t freq;
- if (!has_devfreq(gpu))
+ if (!gpu || !has_devfreq(gpu))
return;
freq = get_freq(gpu);
--
2.38.1
