There is no way to tell how much of the NPU a client uses, or whether its
jobs reach more than one core. Implement the DRM usage stats: account the
time each job occupies a core and report it per client as
drm-engine-npu<n>, along with drm_show_memory_stats() for the BOs.

Jobs can outlive the file that submitted them, so the counters are
refcounted and each job holds a reference. The time covers the whole
period a job owns a core, so it also includes handling the completion
interrupt and the gaps between the tasks of a multi-task job.

For example, teflon running a model two operations deep 3001 times gives:

  drm-engine-npu0:      22719385 ns
  drm-engine-npu1:      23345296 ns
  drm-engine-npu2:      0 ns

The NPU is busy 15.6% of the wall clock time and one core is never used.

Signed-off-by: Sidong Yang <[email protected]>
---
 drivers/accel/rocket/rocket_drv.c | 60 +++++++++++++++++++++++++++++--
 drivers/accel/rocket/rocket_drv.h | 14 ++++++++
 drivers/accel/rocket/rocket_job.c |  7 ++++
 drivers/accel/rocket/rocket_job.h |  4 +++
 4 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/drivers/accel/rocket/rocket_drv.c 
b/drivers/accel/rocket/rocket_drv.c
index 8bbbce594883..5b81d1ecc0e4 100644
--- a/drivers/accel/rocket/rocket_drv.c
+++ b/drivers/accel/rocket/rocket_drv.c
@@ -3,8 +3,10 @@
 
 #include <drm/drm_accel.h>
 #include <drm/drm_drv.h>
+#include <drm/drm_file.h>
 #include <drm/drm_gem.h>
 #include <drm/drm_ioctl.h>
+#include <drm/drm_print.h>
 #include <drm/rocket_accel.h>
 #include <linux/clk.h>
 #include <linux/err.h>
@@ -68,6 +70,25 @@ rocket_iommu_domain_put(struct rocket_iommu_domain *domain)
        kref_put(&domain->kref, rocket_iommu_domain_destroy);
 }
 
+static void
+rocket_engine_usage_destroy(struct kref *kref)
+{
+       kfree(container_of(kref, struct rocket_engine_usage, kref));
+}
+
+struct rocket_engine_usage *
+rocket_engine_usage_get(struct rocket_file_priv *rocket_priv)
+{
+       kref_get(&rocket_priv->engine_usage->kref);
+       return rocket_priv->engine_usage;
+}
+
+void
+rocket_engine_usage_put(struct rocket_engine_usage *usage)
+{
+       kref_put(&usage->kref, rocket_engine_usage_destroy);
+}
+
 static int
 rocket_open(struct drm_device *dev, struct drm_file *file)
 {
@@ -86,10 +107,19 @@ rocket_open(struct drm_device *dev, struct drm_file *file)
        }
 
        rocket_priv->rdev = rdev;
+
+       rocket_priv->engine_usage = kzalloc_flex(*rocket_priv->engine_usage,
+                                                elapsed_ns, rdev->num_cores);
+       if (!rocket_priv->engine_usage) {
+               ret = -ENOMEM;
+               goto err_free;
+       }
+       kref_init(&rocket_priv->engine_usage->kref);
+
        rocket_priv->domain = rocket_iommu_domain_create(rdev->cores[0].dev);
        if (IS_ERR(rocket_priv->domain)) {
                ret = PTR_ERR(rocket_priv->domain);
-               goto err_free;
+               goto err_put_engine_usage;
        }
 
        file->driver_priv = rocket_priv;
@@ -109,6 +139,8 @@ rocket_open(struct drm_device *dev, struct drm_file *file)
        mutex_destroy(&rocket_priv->mm_lock);
        drm_mm_takedown(&rocket_priv->mm);
        rocket_iommu_domain_put(rocket_priv->domain);
+err_put_engine_usage:
+       rocket_engine_usage_put(rocket_priv->engine_usage);
 err_free:
        kfree(rocket_priv);
 err_put_mod:
@@ -125,6 +157,7 @@ rocket_postclose(struct drm_device *dev, struct drm_file 
*file)
        mutex_destroy(&rocket_priv->mm_lock);
        drm_mm_takedown(&rocket_priv->mm);
        rocket_iommu_domain_put(rocket_priv->domain);
+       rocket_engine_usage_put(rocket_priv->engine_usage);
        kfree(rocket_priv);
        module_put(THIS_MODULE);
 }
@@ -139,7 +172,29 @@ static const struct drm_ioctl_desc 
rocket_drm_driver_ioctls[] = {
        ROCKET_IOCTL(FINI_BO, fini_bo),
 };
 
-DEFINE_DRM_ACCEL_FOPS(rocket_accel_driver_fops);
+static void rocket_show_fdinfo(struct drm_printer *p, struct drm_file *file)
+{
+       struct rocket_device *rdev = to_rocket_device(file->minor->dev);
+       struct rocket_file_priv *rocket_priv = file->driver_priv;
+       unsigned int core;
+
+       /*
+        * These are estimates: the time is taken around the whole period a job
+        * occupies a core, so it also covers handling the completion interrupt
+        * and, for a job made of several tasks, the gaps between them.
+        */
+       for (core = 0; core < rdev->num_cores; core++)
+               drm_printf(p, "drm-engine-npu%u:\t%llu ns\n", core,
+                          rocket_priv->engine_usage->elapsed_ns[core]);
+
+       drm_show_memory_stats(p, file);
+}
+
+static const struct file_operations rocket_accel_driver_fops = {
+       .owner = THIS_MODULE,
+       DRM_ACCEL_FOPS,
+       .show_fdinfo = drm_show_fdinfo,
+};
 
 /*
  * Rocket driver version:
@@ -150,6 +205,7 @@ static const struct drm_driver rocket_drm_driver = {
        .open                   = rocket_open,
        .postclose              = rocket_postclose,
        .gem_create_object      = rocket_gem_create_object,
+       .show_fdinfo            = rocket_show_fdinfo,
        .ioctls                 = rocket_drm_driver_ioctls,
        .num_ioctls             = ARRAY_SIZE(rocket_drm_driver_ioctls),
        .fops                   = &rocket_accel_driver_fops,
diff --git a/drivers/accel/rocket/rocket_drv.h 
b/drivers/accel/rocket/rocket_drv.h
index 2c673bb99ccc..eff5c2ac54d1 100644
--- a/drivers/accel/rocket/rocket_drv.h
+++ b/drivers/accel/rocket/rocket_drv.h
@@ -16,6 +16,15 @@ struct rocket_iommu_domain {
        struct kref kref;
 };
 
+/*
+ * Time each core has spent running a client's jobs, in nanoseconds, indexed by
+ * core. Jobs hold a reference, as they can outlive the file that submitted 
them.
+ */
+struct rocket_engine_usage {
+       struct kref kref;
+       u64 elapsed_ns[];
+};
+
 struct rocket_file_priv {
        struct rocket_device *rdev;
 
@@ -24,9 +33,14 @@ struct rocket_file_priv {
        struct mutex mm_lock;
 
        struct drm_sched_entity sched_entity;
+
+       struct rocket_engine_usage *engine_usage;
 };
 
 struct rocket_iommu_domain *rocket_iommu_domain_get(struct rocket_file_priv 
*rocket_priv);
 void rocket_iommu_domain_put(struct rocket_iommu_domain *domain);
 
+struct rocket_engine_usage *rocket_engine_usage_get(struct rocket_file_priv 
*rocket_priv);
+void rocket_engine_usage_put(struct rocket_engine_usage *usage);
+
 #endif
diff --git a/drivers/accel/rocket/rocket_job.c 
b/drivers/accel/rocket/rocket_job.c
index ce994748dd5d..c0ffbccfb6cc 100644
--- a/drivers/accel/rocket/rocket_job.c
+++ b/drivers/accel/rocket/rocket_job.c
@@ -13,6 +13,7 @@
 #include <linux/iommu.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/sched/clock.h>
 
 #include "rocket_core.h"
 #include "rocket_device.h"
@@ -265,6 +266,7 @@ static void rocket_job_cleanup(struct kref *ref)
        unsigned int i;
 
        rocket_iommu_domain_put(job->domain);
+       rocket_engine_usage_put(job->engine_usage);
 
        dma_fence_put(job->done_fence);
        dma_fence_put(job->inference_done_fence);
@@ -351,6 +353,7 @@ static struct dma_fence *rocket_job_run(struct 
drm_sched_job *sched_job)
 
        scoped_guard(mutex, &core->job_lock) {
                core->in_flight_job = job;
+               job->start_ns = local_clock();
                rocket_job_hw_submit(core, job);
        }
 
@@ -379,6 +382,9 @@ static void rocket_job_handle_irq(struct rocket_core *core)
                                return;
                        }
 
+                       
core->in_flight_job->engine_usage->elapsed_ns[core->index] +=
+                               local_clock() - core->in_flight_job->start_ns;
+
                        iommu_detach_group(NULL, iommu_group_get(core->dev));
                        dma_fence_signal(core->in_flight_job->done_fence);
                        pm_runtime_put_autosuspend(core->dev);
@@ -587,6 +593,7 @@ static int rocket_ioctl_submit_job(struct drm_device *dev, 
struct drm_file *file
 
        rjob->rdev = rdev;
        rjob->domain = rocket_iommu_domain_get(file_priv);
+       rjob->engine_usage = rocket_engine_usage_get(file_priv);
 
        ret = drm_sched_job_init(&rjob->base,
                                 &file_priv->sched_entity,
diff --git a/drivers/accel/rocket/rocket_job.h 
b/drivers/accel/rocket/rocket_job.h
index 4ae00feec3b9..14aa78aebc99 100644
--- a/drivers/accel/rocket/rocket_job.h
+++ b/drivers/accel/rocket/rocket_job.h
@@ -38,6 +38,10 @@ struct rocket_job {
 
        struct rocket_iommu_domain *domain;
 
+       /* When the job was handed to a core, and where to account the time */
+       u64 start_ns;
+       struct rocket_engine_usage *engine_usage;
+
        struct kref refcount;
 };
 

base-commit: a1e63ab695ad76850ab9787b9eb6aab695dc2965
-- 
2.53.0

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