From: Rob Clark robdclark@chromium.org
Add a short delay before clamping to idle frequency on active->idle transition. It takes ~0.5ms to increase the freq again on the next idle->active transition, so this helps avoid extra freq transitions on workloads that bounce between CPU and GPU.
Signed-off-by: Rob Clark robdclark@chromium.org --- Note that this sort of re-introduces the theoretical race solved by [1].. but that should not be a problem with something along the lines of [2].
[1] https://patchwork.freedesktop.org/patch/455910/?series=95111&rev=1 [2] https://patchwork.freedesktop.org/patch/455928/?series=95119&rev=1
drivers/gpu/drm/msm/msm_gpu.h | 7 +++++ drivers/gpu/drm/msm/msm_gpu_devfreq.c | 38 +++++++++++++++++++++------ 2 files changed, 37 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h index 32a859307e81..2fcb6c195865 100644 --- a/drivers/gpu/drm/msm/msm_gpu.h +++ b/drivers/gpu/drm/msm/msm_gpu.h @@ -120,6 +120,13 @@ struct msm_gpu_devfreq { * it is inactive. */ unsigned long idle_freq; + + /** + * idle_work: + * + * Used to delay clamping to idle freq on active->idle transition. + */ + struct msm_hrtimer_work idle_work; };
struct msm_gpu { diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c index 15b64f35c0f6..36e1930ee26d 100644 --- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c +++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c @@ -96,8 +96,12 @@ static struct devfreq_dev_profile msm_devfreq_profile = { .get_cur_freq = msm_devfreq_get_cur_freq, };
+static void msm_devfreq_idle_work(struct kthread_work *work); + void msm_devfreq_init(struct msm_gpu *gpu) { + struct msm_gpu_devfreq *df = &gpu->devfreq; + /* We need target support to do devfreq */ if (!gpu->funcs->gpu_busy) return; @@ -113,25 +117,27 @@ void msm_devfreq_init(struct msm_gpu *gpu) msm_devfreq_profile.freq_table = NULL; msm_devfreq_profile.max_state = 0;
- gpu->devfreq.devfreq = devm_devfreq_add_device(&gpu->pdev->dev, + df->devfreq = devm_devfreq_add_device(&gpu->pdev->dev, &msm_devfreq_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND, NULL);
- if (IS_ERR(gpu->devfreq.devfreq)) { + if (IS_ERR(df->devfreq)) { DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize GPU devfreq\n"); - gpu->devfreq.devfreq = NULL; + df->devfreq = NULL; return; }
- devfreq_suspend_device(gpu->devfreq.devfreq); + devfreq_suspend_device(df->devfreq);
- gpu->cooling = of_devfreq_cooling_register(gpu->pdev->dev.of_node, - gpu->devfreq.devfreq); + gpu->cooling = of_devfreq_cooling_register(gpu->pdev->dev.of_node, df->devfreq); if (IS_ERR(gpu->cooling)) { DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't register GPU cooling device\n"); gpu->cooling = NULL; } + + msm_hrtimer_work_init(&df->idle_work, gpu->worker, msm_devfreq_idle_work, + CLOCK_MONOTONIC, HRTIMER_MODE_REL); }
void msm_devfreq_cleanup(struct msm_gpu *gpu) @@ -179,6 +185,11 @@ void msm_devfreq_active(struct msm_gpu *gpu) unsigned int idle_time; unsigned long target_freq = df->idle_freq;
+ /* + * Cancel any pending transition to idle frequency: + */ + hrtimer_cancel(&df->idle_work.timer); + /* * Hold devfreq lock to synchronize with get_dev_status()/ * target() callbacks @@ -209,9 +220,12 @@ void msm_devfreq_active(struct msm_gpu *gpu) mutex_unlock(&df->devfreq->lock); }
-void msm_devfreq_idle(struct msm_gpu *gpu) + +static void msm_devfreq_idle_work(struct kthread_work *work) { - struct msm_gpu_devfreq *df = &gpu->devfreq; + struct msm_gpu_devfreq *df = container_of(work, + struct msm_gpu_devfreq, idle_work.work); + struct msm_gpu *gpu = container_of(df, struct msm_gpu, devfreq); unsigned long idle_freq, target_freq = 0;
/* @@ -229,3 +243,11 @@ void msm_devfreq_idle(struct msm_gpu *gpu)
mutex_unlock(&df->devfreq->lock); } + +void msm_devfreq_idle(struct msm_gpu *gpu) +{ + struct msm_gpu_devfreq *df = &gpu->devfreq; + + msm_hrtimer_queue_work(&df->idle_work, ms_to_ktime(1), + HRTIMER_MODE_ABS); +}