Re: [PATCH v2 3/7] drm/amdgpu: Add new function to put GPU power profile

From: Yadav, Arvind
Date: Mon Aug 21 2023 - 10:41:05 EST



On 8/21/2023 7:09 PM, Shashank Sharma wrote:

On 21/08/2023 08:47, Arvind Yadav wrote:
This patch adds a function which will clear the GPU
power profile after job finished.

This is how it works:
- schedular will set the GPU power profile based on ring_type.
- Schedular will clear the GPU Power profile once job finished.
- Here, the *_workload_profile_set function will set the GPU
   power profile and the *_workload_profile_put function will
   schedule the smu_delayed_work task after 100ms delay. This
   smu_delayed_work task will clear a GPU power profile if any
   new jobs are not scheduled within 100 ms. But if any new job
   comes within 100ms then the *_workload_profile_set function
   will cancel this work and set the GPU power profile based on
   preferences.

v2:
- Splitting workload_profile_set and workload_profile_put
   into two separate patches.
- Addressed review comment.

Cc: Shashank Sharma <shashank.sharma@xxxxxxx>
Cc: Christian Koenig <christian.koenig@xxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Arvind Yadav <Arvind.Yadav@xxxxxxx>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_workload.c  | 97 +++++++++++++++++++
  drivers/gpu/drm/amd/include/amdgpu_workload.h |  3 +
  2 files changed, 100 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_workload.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_workload.c
index e661cc5b3d92..6367eb88a44d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_workload.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_workload.c
@@ -24,6 +24,9 @@
    #include "amdgpu.h"
  +/* 100 millsecond timeout */
+#define SMU_IDLE_TIMEOUT    msecs_to_jiffies(100)
+
  static enum PP_SMC_POWER_PROFILE
  ring_to_power_profile(uint32_t ring_type)
  {
@@ -59,6 +62,80 @@ amdgpu_power_profile_set(struct amdgpu_device *adev,
      return ret;
  }
  +static int
+amdgpu_power_profile_clear(struct amdgpu_device *adev,
+               enum PP_SMC_POWER_PROFILE profile)
+{
+    int ret = amdgpu_dpm_switch_power_profile(adev, profile, false);
+
+    if (!ret) {
+        /* Clear the bit for the submitted workload profile */
+        adev->smu_workload.submit_workload_status &= ~(1 << profile);
+    }
+
+    return ret;
+}
+
+static void
+amdgpu_power_profile_idle_work_handler(struct work_struct *work)
+{
+
+    struct amdgpu_smu_workload *workload = container_of(work,
+                              struct amdgpu_smu_workload,
+                              smu_delayed_work.work);
+    struct amdgpu_device *adev = workload->adev;
+    bool reschedule = false;
+    int index  = fls(workload->submit_workload_status);
+    int ret;
+
We should check validity and range of index here before before using it below.
Noted.

+ mutex_lock(&workload->workload_lock);
+    for (; index > 0; index--) {
+        int val = atomic_read(&workload->power_profile_ref[index]);
+
+        if (val) {
+            reschedule = true;
+        } else {
+            if (workload->submit_workload_status &
+                (1 << index)) {
+                ret = amdgpu_power_profile_clear(adev, index);
+                if (ret) {
+                    DRM_WARN("Failed to clear workload %s,error = %d\n",
+                         amdgpu_workload_mode_name[index], ret);
+                    goto exit;
instead of exiting, we might wanna continue the loop here, just to check if we are able to reset another profile in the next attempt.
Noted.
+                }
+            }
+        }
+    }
A blank line recommended here.
Noted.
+    if (reschedule)
+ schedule_delayed_work(&workload->smu_delayed_work,
+                      SMU_IDLE_TIMEOUT);
+exit:
+    mutex_unlock(&workload->workload_lock);
+}
+
+void amdgpu_workload_profile_put(struct amdgpu_device *adev,
+                 uint32_t ring_type)
+{
+    struct amdgpu_smu_workload *workload = &adev->smu_workload;
+    enum PP_SMC_POWER_PROFILE profile = ring_to_power_profile(ring_type);
+
+    if (profile == PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT)
+        return;
+
+    mutex_lock(&workload->workload_lock);
+
+    if (!atomic_read(&workload->power_profile_ref[profile])) {
+        DRM_WARN("Power profile %s ref. count error\n",
+             amdgpu_workload_mode_name[profile]);
+    } else {
+ atomic_dec(&workload->power_profile_ref[profile]);
+ schedule_delayed_work(&workload->smu_delayed_work,
+                      SMU_IDLE_TIMEOUT);
We don't want to schedule this work everytime a power profile is put, but we want to do that only when a power profile ref count reaches '0'. So you might want to check the ref_count, and schedule the work under a if (!ref_count) condition.
Noted.

+    }
+
+    mutex_unlock(&workload->workload_lock);
+}
+
  void amdgpu_workload_profile_set(struct amdgpu_device *adev,
                   uint32_t ring_type)
  {
@@ -70,13 +147,30 @@ void amdgpu_workload_profile_set(struct amdgpu_device *adev,
          return;
        mutex_lock(&workload->workload_lock);
+ cancel_delayed_work_sync(&workload->smu_delayed_work);
        ret = amdgpu_power_profile_set(adev, profile);
      if (ret) {
          DRM_WARN("Failed to set workload profile to %s, error = %d\n",
               amdgpu_workload_mode_name[profile], ret);
+        goto exit;
+    }
+
+    /* Clear the already finished jobs of higher power profile*/

We are not clearing the jobs here, but their power profiles.

I would recommend a little rework in the comment like "As we cancelled the delayed work, check and clear the pending higher power profiles set by previous jobs which are done now"

Noted.
+    for (int index = fls(workload->submit_workload_status);
The index can be initialized above, like the put function for loop.
+         index > profile; index--) {
+        if (!atomic_read(&workload->power_profile_ref[index]) &&
+            workload->submit_workload_status & (1 << index)) {
+            ret = amdgpu_power_profile_clear(adev, index);
After clearing the power profile, we should also clear the respective workload->submit_workload_status bit as well, right ?
We are clearing in submit_workload_status bit in amdgpu_power_profile_clear()
+            if (ret) {
+                DRM_WARN("Failed to clear workload %s, err = %d\n",
+                     amdgpu_workload_mode_name[profile], ret);
+                goto exit;

Same as previous about continuing the loop.

Noted.

Thank You,
~Arvind


- Shashank

+            }
+        }
      }
  +exit:
      mutex_unlock(&workload->workload_lock);
  }
  @@ -87,6 +181,8 @@ void amdgpu_workload_profile_init(struct amdgpu_device *adev)
      adev->smu_workload.initialized = true;
        mutex_init(&adev->smu_workload.workload_lock);
+ INIT_DELAYED_WORK(&adev->smu_workload.smu_delayed_work,
+              amdgpu_power_profile_idle_work_handler);
  }
    void amdgpu_workload_profile_fini(struct amdgpu_device *adev)
@@ -94,6 +190,7 @@ void amdgpu_workload_profile_fini(struct amdgpu_device *adev)
      if (!adev->smu_workload.initialized)
          return;
  + cancel_delayed_work_sync(&adev->smu_workload.smu_delayed_work);
      adev->smu_workload.submit_workload_status = 0;
      adev->smu_workload.initialized = false;
      mutex_destroy(&adev->smu_workload.workload_lock);
diff --git a/drivers/gpu/drm/amd/include/amdgpu_workload.h b/drivers/gpu/drm/amd/include/amdgpu_workload.h
index 5022f28fc2f9..ee1f87257f2d 100644
--- a/drivers/gpu/drm/amd/include/amdgpu_workload.h
+++ b/drivers/gpu/drm/amd/include/amdgpu_workload.h
@@ -46,6 +46,9 @@ static const char * const amdgpu_workload_mode_name[] = {
      "Window3D"
  };
  +void amdgpu_workload_profile_put(struct amdgpu_device *adev,
+                 uint32_t ring_type);
+
  void amdgpu_workload_profile_set(struct amdgpu_device *adev,
                   uint32_t ring_type);