[PATCH v3 2/2] drm/msm: Expose client engine utilization via fdinfo

From: Rob Clark
Date: Thu Jun 09 2022 - 13:42:24 EST


From: Rob Clark <robdclark@xxxxxxxxxxxx>

Similar to AMD commit
874442541133 ("drm/amdgpu: Add show_fdinfo() interface"), using the
infrastructure added in previous patches, we add basic client info
and GPU engine utilisation for msm.

Example output:

# cat /proc/`pgrep glmark2`/fdinfo/6
pos: 0
flags: 02400002
mnt_id: 21
ino: 162
drm-driver: msm
drm-client-id: 7
drm-engine-gpu: 1734371319 ns
drm-cycles-gpu: 1153645024
drm-maxfreq-gpu: 800000000 Hz

See also: https://patchwork.freedesktop.org/patch/468505/

v2: Add dev-maxfreq-$engine and update drm-usage-stats.rst
v3: spelling and compiler warning

Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
Documentation/gpu/drm-usage-stats.rst | 21 +++++++++++++++++++++
drivers/gpu/drm/msm/msm_drv.c | 19 ++++++++++++++++++-
drivers/gpu/drm/msm/msm_gpu.c | 21 +++++++++++++++++++--
drivers/gpu/drm/msm/msm_gpu.h | 19 +++++++++++++++++++
4 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/Documentation/gpu/drm-usage-stats.rst b/Documentation/gpu/drm-usage-stats.rst
index 6c9f166a8d6f..92c5117368d7 100644
--- a/Documentation/gpu/drm-usage-stats.rst
+++ b/Documentation/gpu/drm-usage-stats.rst
@@ -105,6 +105,27 @@ object belong to this client, in the respective memory region.
Default unit shall be bytes with optional unit specifiers of 'KiB' or 'MiB'
indicating kibi- or mebi-bytes.

+- drm-cycles-<str> <uint>
+
+Engine identifier string must be the same as the one specified in the
+drm-engine-<str> tag and shall contain the number of busy cycles for the given
+engine.
+
+Values are not required to be constantly monotonic if it makes the driver
+implementation easier, but are required to catch up with the previously reported
+larger value within a reasonable period. Upon observing a value lower than what
+was previously read, userspace is expected to stay with that larger previous
+value until a monotonic update is seen.
+
+- drm-maxfreq-<str> <uint> [Hz|MHz|KHz]
+
+Engine identifier string must be the same as the one specified in the
+drm-engine-<str> tag and shall contain the maximum frequency for the given
+engine. Taken together with drm-cycles-<str>, this can be used to calculate
+percentage utilization of the engine, whereas drm-engine-<str> only reflects
+time active without considering what frequency the engine is operating as a
+percentage of it's maximum frequency.
+
===============================
Driver specific implementations
===============================
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 14ab9a627d8b..57a66093e671 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -948,7 +948,24 @@ static const struct drm_ioctl_desc msm_ioctls[] = {
DRM_IOCTL_DEF_DRV(MSM_SUBMITQUEUE_QUERY, msm_ioctl_submitqueue_query, DRM_RENDER_ALLOW),
};

-DEFINE_DRM_GEM_FOPS(fops);
+static void msm_fop_show_fdinfo(struct seq_file *m, struct file *f)
+{
+ struct drm_file *file = f->private_data;
+ struct drm_device *dev = file->minor->dev;
+ struct msm_drm_private *priv = dev->dev_private;
+ struct drm_printer p = drm_seq_file_printer(m);
+
+ if (!priv->gpu)
+ return;
+
+ msm_gpu_show_fdinfo(priv->gpu, file->driver_priv, &p);
+}
+
+static const struct file_operations fops = {
+ .owner = THIS_MODULE,
+ DRM_GEM_FOPS,
+ .show_fdinfo = msm_fop_show_fdinfo,
+};

static const struct drm_driver msm_driver = {
.driver_features = DRIVER_GEM |
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 244511f85044..f99292eaf529 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -4,6 +4,8 @@
* Author: Rob Clark <robdclark@xxxxxxxxx>
*/

+#include "drm/drm_drv.h"
+
#include "msm_gpu.h"
#include "msm_gem.h"
#include "msm_mmu.h"
@@ -146,6 +148,16 @@ int msm_gpu_pm_suspend(struct msm_gpu *gpu)
return 0;
}

+void msm_gpu_show_fdinfo(struct msm_gpu *gpu, struct msm_file_private *ctx,
+ struct drm_printer *p)
+{
+ drm_printf(p, "drm-driver:\t%s\n", gpu->dev->driver->name);
+ drm_printf(p, "drm-client-id:\t%u\n", ctx->seqno);
+ drm_printf(p, "drm-engine-gpu:\t%llu ns\n", ctx->elapsed_ns);
+ drm_printf(p, "drm-cycles-gpu:\t%llu\n", ctx->cycles);
+ drm_printf(p, "drm-maxfreq-gpu:\t%u Hz\n", gpu->fast_rate);
+}
+
int msm_gpu_hw_init(struct msm_gpu *gpu)
{
int ret;
@@ -652,7 +664,7 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
{
int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
volatile struct msm_gpu_submit_stats *stats;
- u64 elapsed, clock = 0;
+ u64 elapsed, clock = 0, cycles;
unsigned long flags;

stats = &ring->memptrs->stats[index];
@@ -660,12 +672,17 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
elapsed = (stats->alwayson_end - stats->alwayson_start) * 10000;
do_div(elapsed, 192);

+ cycles = stats->cpcycles_end - stats->cpcycles_start;
+
/* Calculate the clock frequency from the number of CP cycles */
if (elapsed) {
- clock = (stats->cpcycles_end - stats->cpcycles_start) * 1000;
+ clock = cycles * 1000;
do_div(clock, elapsed);
}

+ submit->queue->ctx->elapsed_ns += elapsed;
+ submit->queue->ctx->cycles += cycles;
+
trace_msm_gpu_submit_retired(submit, elapsed, clock,
stats->alwayson_start, stats->alwayson_end);

diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 6def00883046..4911943ba53b 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -361,6 +361,22 @@ struct msm_file_private {
/** cmdline: Overridden task cmdline, see MSM_PARAM_CMDLINE */
char *cmdline;

+ /**
+ * elapsed:
+ *
+ * The total (cumulative) elapsed time GPU was busy with rendering
+ * from this context in ns.
+ */
+ uint64_t elapsed_ns;
+
+ /**
+ * cycles:
+ *
+ * The total (cumulative) GPU cycles elapsed attributed to this
+ * context.
+ */
+ uint64_t cycles;
+
/**
* entities:
*
@@ -544,6 +560,9 @@ static inline void gpu_write64(struct msm_gpu *gpu, u32 lo, u32 hi, u64 val)
int msm_gpu_pm_suspend(struct msm_gpu *gpu);
int msm_gpu_pm_resume(struct msm_gpu *gpu);

+void msm_gpu_show_fdinfo(struct msm_gpu *gpu, struct msm_file_private *ctx,
+ struct drm_printer *p);
+
int msm_submitqueue_init(struct drm_device *drm, struct msm_file_private *ctx);
struct msm_gpu_submitqueue *msm_submitqueue_get(struct msm_file_private *ctx,
u32 id);
--
2.36.1