2022-11-29 17:57:32

by Rob Clark

Subject: [PATCH] drm/virtio: Spiff out cmd queue/response traces

From: Rob Clark <[email protected]>

Add a sequence # for more easily matching up cmd/resp, and the # of free
slots in the virtqueue to more easily see starvation issues.

Signed-off-by: Rob Clark <[email protected]>
---
drivers/gpu/drm/virtio/virtgpu_drv.h | 3 +++
drivers/gpu/drm/virtio/virtgpu_trace.h | 20 ++++++++++++--------
drivers/gpu/drm/virtio/virtgpu_vq.c | 13 ++++++++++---
3 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 9b98470593b0..cdc208d9238c 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -166,6 +166,8 @@ struct virtio_gpu_vbuffer {

struct virtio_gpu_object_array *objs;
struct list_head list;
+
+ uint32_t seqno;
};

struct virtio_gpu_output {
@@ -195,6 +197,7 @@ struct virtio_gpu_queue {
spinlock_t qlock;
wait_queue_head_t ack_queue;
struct work_struct dequeue_work;
+ uint32_t seqno;
};

struct virtio_gpu_drv_capset {
diff --git a/drivers/gpu/drm/virtio/virtgpu_trace.h b/drivers/gpu/drm/virtio/virtgpu_trace.h
index 711ecc2bd241..087e860a66f7 100644
--- a/drivers/gpu/drm/virtio/virtgpu_trace.h
+++ b/drivers/gpu/drm/virtio/virtgpu_trace.h
@@ -9,8 +9,8 @@
#define TRACE_INCLUDE_FILE virtgpu_trace

DECLARE_EVENT_CLASS(virtio_gpu_cmd,
- TP_PROTO(struct virtqueue *vq, struct virtio_gpu_ctrl_hdr *hdr),
- TP_ARGS(vq, hdr),
+ TP_PROTO(struct virtqueue *vq, struct virtio_gpu_ctrl_hdr *hdr, u32 seqno),
+ TP_ARGS(vq, hdr, seqno),
TP_STRUCT__entry(
__field(int, dev)
__field(unsigned int, vq)
@@ -19,6 +19,8 @@ DECLARE_EVENT_CLASS(virtio_gpu_cmd,
__field(u32, flags)
__field(u64, fence_id)
__field(u32, ctx_id)
+ __field(u32, num_free)
+ __field(u32, seqno)
),
TP_fast_assign(
__entry->dev = vq->vdev->index;
@@ -28,21 +30,23 @@ DECLARE_EVENT_CLASS(virtio_gpu_cmd,
__entry->flags = le32_to_cpu(hdr->flags);
__entry->fence_id = le64_to_cpu(hdr->fence_id);
__entry->ctx_id = le32_to_cpu(hdr->ctx_id);
+ __entry->num_free = vq->num_free;
+ __entry->seqno = seqno;
),
- TP_printk("vdev=%d vq=%u name=%s type=0x%x flags=0x%x fence_id=%llu ctx_id=%u",
+ TP_printk("vdev=%d vq=%u name=%s type=0x%x flags=0x%x fence_id=%llu ctx_id=%u num_free=%u seqno=%u",
__entry->dev, __entry->vq, __entry->name,
__entry->type, __entry->flags, __entry->fence_id,
- __entry->ctx_id)
+ __entry->ctx_id, __entry->num_free, __entry->seqno)
);

DEFINE_EVENT(virtio_gpu_cmd, virtio_gpu_cmd_queue,
- TP_PROTO(struct virtqueue *vq, struct virtio_gpu_ctrl_hdr *hdr),
- TP_ARGS(vq, hdr)
+ TP_PROTO(struct virtqueue *vq, struct virtio_gpu_ctrl_hdr *hdr, u32 seqno),
+ TP_ARGS(vq, hdr, seqno)
);

DEFINE_EVENT(virtio_gpu_cmd, virtio_gpu_cmd_response,
- TP_PROTO(struct virtqueue *vq, struct virtio_gpu_ctrl_hdr *hdr),
- TP_ARGS(vq, hdr)
+ TP_PROTO(struct virtqueue *vq, struct virtio_gpu_ctrl_hdr *hdr, u32 seqno),
+ TP_ARGS(vq, hdr, seqno)
);

#endif
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 9ff8660b50ad..a04a9b20896d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -215,7 +215,7 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct *work)
list_for_each_entry(entry, &reclaim_list, list) {
resp = (struct virtio_gpu_ctrl_hdr *)entry->resp_buf;

- trace_virtio_gpu_cmd_response(vgdev->ctrlq.vq, resp);
+ trace_virtio_gpu_cmd_response(vgdev->ctrlq.vq, resp, entry->seqno);

if (resp->type != cpu_to_le32(VIRTIO_GPU_RESP_OK_NODATA)) {
if (le32_to_cpu(resp->type) >= VIRTIO_GPU_RESP_ERR_UNSPEC) {
@@ -261,6 +261,10 @@ void virtio_gpu_dequeue_cursor_func(struct work_struct *work)
spin_unlock(&vgdev->cursorq.qlock);

list_for_each_entry_safe(entry, tmp, &reclaim_list, list) {
+ struct virtio_gpu_ctrl_hdr *resp =
+ (struct virtio_gpu_ctrl_hdr *)entry->resp_buf;
+
+ trace_virtio_gpu_cmd_response(vgdev->cursorq.vq, resp, entry->seqno);
list_del(&entry->list);
free_vbuf(vgdev, entry);
}
@@ -353,7 +357,8 @@ static int virtio_gpu_queue_ctrl_sgs(struct virtio_gpu_device *vgdev,
ret = virtqueue_add_sgs(vq, sgs, outcnt, incnt, vbuf, GFP_ATOMIC);
WARN_ON(ret);

- trace_virtio_gpu_cmd_queue(vq, virtio_gpu_vbuf_ctrl_hdr(vbuf));
+ vbuf->seqno = ++vgdev->ctrlq.seqno;
+ trace_virtio_gpu_cmd_queue(vq, virtio_gpu_vbuf_ctrl_hdr(vbuf), vbuf->seqno);

atomic_inc(&vgdev->pending_commands);

@@ -465,8 +470,10 @@ static void virtio_gpu_queue_cursor(struct virtio_gpu_device *vgdev,
spin_lock(&vgdev->cursorq.qlock);
goto retry;
} else {
+ vbuf->seqno = ++vgdev->cursorq.seqno;
trace_virtio_gpu_cmd_queue(vq,
- virtio_gpu_vbuf_ctrl_hdr(vbuf));
+ virtio_gpu_vbuf_ctrl_hdr(vbuf),
+ vbuf->seqno);

notify = virtqueue_kick_prepare(vq);
}
--
2.38.1

2022-11-29 18:55:46

by Dmitry Osipenko

Subject: Re: [PATCH] drm/virtio: Spiff out cmd queue/response traces

On 11/29/22 20:43, Rob Clark wrote:
> From: Rob Clark <[email protected]>
>
> Add a sequence # for more easily matching up cmd/resp, and the # of free
> slots in the virtqueue to more easily see starvation issues.
>
> Signed-off-by: Rob Clark <[email protected]>
> ---
> drivers/gpu/drm/virtio/virtgpu_drv.h | 3 +++
> drivers/gpu/drm/virtio/virtgpu_trace.h | 20 ++++++++++++--------
> drivers/gpu/drm/virtio/virtgpu_vq.c | 13 ++++++++++---
> 3 files changed, 25 insertions(+), 11 deletions(-)

Reviewed-by: Dmitry Osipenko <[email protected]>

--
Best regards,
Dmitry