From: Shik Chen <[email protected]>
Majorly based on [1], with the following tweaks:
* Use div_u64 for u64 divisions
* Calculate standard deviation
* Fix an uninitialized |min| field for header
* Apply clang-format
[1] https://git.kernel.org/pub/scm/linux/kernel/git/kbingham/rcar.git/commit/?h=uvc/async-ml&id=cebbd1b629bbe5f856ec5dc7591478c003f5a944
Signed-off-by: Shik Chen <[email protected]>
---
drivers/media/usb/uvc/uvc_video.c | 163 +++++++++++++++++++++++++++++-
drivers/media/usb/uvc/uvcvideo.h | 21 ++++
2 files changed, 181 insertions(+), 3 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 9e90b261428a..d3a515015003 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -906,12 +906,61 @@ static void uvc_video_stats_update(struct uvc_streaming *stream)
memset(&stream->stats.frame, 0, sizeof(stream->stats.frame));
}
+size_t uvc_video_dump_time_stats(char *buf, size_t size,
+ struct uvc_stats_time *stat, const char *pfx)
+{
+ unsigned int avg = 0;
+ unsigned int std = 0;
+
+ if (stat->qty) {
+ avg = div_u64(stat->duration, stat->qty);
+ std = int_sqrt64(div_u64(stat->duration2, stat->qty) -
+ avg * avg);
+ }
+
+ /* Stat durations are in nanoseconds, we present in micro-seconds */
+ return scnprintf(
+ buf, size,
+ "%s: %llu/%u uS/qty: %u.%03u avg %u.%03u std %u.%03u min %u.%03u max (uS)\n",
+ pfx, div_u64(stat->duration, 1000), stat->qty, avg / 1000,
+ avg % 1000, std / 1000, std % 1000, stat->min / 1000,
+ stat->min % 1000, stat->max / 1000, stat->max % 1000);
+}
+
+size_t uvc_video_dump_speed(char *buf, size_t size, const char *pfx, u64 bytes,
+ u64 milliseconds)
+{
+ unsigned int rate = 0;
+ bool gbit = false;
+
+ if (milliseconds)
+ rate = div_u64(bytes * 8, milliseconds);
+
+ if (rate >= 1000000) {
+ gbit = true;
+ rate /= 1000;
+ }
+
+ /*
+ * bits/milliseconds == kilobits/seconds,
+ * presented here as Mbits/s (or Gbit/s) with 3 decimal places
+ */
+ return scnprintf(buf, size, "%s: %d.%03d %sbits/s\n", pfx, rate / 1000,
+ rate % 1000, gbit ? "G" : "M");
+}
+
size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
size_t size)
{
+ u64 bytes = stream->stats.stream.bytes; /* Single sample */
+ unsigned int empty_ratio = 0;
unsigned int scr_sof_freq;
unsigned int duration;
+ unsigned int fps = 0;
size_t count = 0;
+ u64 cpu = 0;
+ u64 cpu_q = 0;
+ u32 cpu_r = 0;
/* Compute the SCR.SOF frequency estimate. At the nominal 1kHz SOF
* frequency this will not overflow before more than 1h.
@@ -924,12 +973,19 @@ size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
else
scr_sof_freq = 0;
+ if (stream->stats.stream.nb_packets)
+ empty_ratio = stream->stats.stream.nb_empty * 100 /
+ stream->stats.stream.nb_packets;
+
count += scnprintf(buf + count, size - count,
- "frames: %u\npackets: %u\nempty: %u\n"
- "errors: %u\ninvalid: %u\n",
+ "frames: %u\n"
+ "packets: %u\n"
+ "empty: %u (%u %%)\n"
+ "errors: %u\n"
+ "invalid: %u\n",
stream->stats.stream.nb_frames,
stream->stats.stream.nb_packets,
- stream->stats.stream.nb_empty,
+ stream->stats.stream.nb_empty, empty_ratio,
stream->stats.stream.nb_errors,
stream->stats.stream.nb_invalid);
count += scnprintf(buf + count, size - count,
@@ -946,6 +1002,55 @@ size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
stream->stats.stream.min_sof,
stream->stats.stream.max_sof,
scr_sof_freq / 1000, scr_sof_freq % 1000);
+ count += scnprintf(buf + count, size - count,
+ "bytes %lld : duration %d\n", bytes, duration);
+
+ if (duration != 0) {
+ /* Duration is in milliseconds, * 100 to gain 2 dp precision */
+ fps = stream->stats.stream.nb_frames * 1000 * 100 / duration;
+ /* CPU usage as a % with 6 decimal places */
+ cpu = div_u64(stream->stats.urbstat.decode.duration, duration) *
+ 100;
+ }
+
+ count += scnprintf(buf + count, size - count, "FPS: %u.%02u\n",
+ fps / 100, fps % 100);
+
+ /* Processing Times */
+
+ count += uvc_video_dump_time_stats(buf + count, size - count,
+ &stream->stats.urbstat.urb, "URB");
+ count += uvc_video_dump_time_stats(buf + count, size - count,
+ &stream->stats.urbstat.header,
+ "header");
+ count += uvc_video_dump_time_stats(buf + count, size - count,
+ &stream->stats.urbstat.latency,
+ "latency");
+ count += uvc_video_dump_time_stats(buf + count, size - count,
+ &stream->stats.urbstat.decode,
+ "decode");
+
+ /* Processing Speeds */
+
+ /* This should be representative of the memory bus / cpu speed */
+ count += uvc_video_dump_speed(
+ buf + count, size - count, "raw decode speed", bytes,
+ div_u64(stream->stats.urbstat.decode.duration, 1000000));
+
+ /* Raw bus speed - scheduling latencies */
+ count += uvc_video_dump_speed(
+ buf + count, size - count, "raw URB handling speed", bytes,
+ div_u64(stream->stats.urbstat.urb.duration, 1000000));
+
+ /* Throughput against wall clock time, stream duration is in millis*/
+ count += uvc_video_dump_speed(buf + count, size - count, "throughput",
+ bytes, duration);
+
+ cpu_q = div_u64_rem(cpu, 1000000, &cpu_r);
+
+ /* Determine the 'CPU Usage' of our URB processing */
+ count += scnprintf(buf + count, size - count,
+ "URB decode CPU usage %llu.%06u %%\n", cpu_q, cpu_r);
return count;
}
@@ -954,6 +1059,11 @@ static void uvc_video_stats_start(struct uvc_streaming *stream)
{
memset(&stream->stats, 0, sizeof(stream->stats));
stream->stats.stream.min_sof = 2048;
+
+ stream->stats.urbstat.header.min = -1;
+ stream->stats.urbstat.latency.min = -1;
+ stream->stats.urbstat.decode.min = -1;
+ stream->stats.urbstat.urb.min = -1;
}
static void uvc_video_stats_stop(struct uvc_streaming *stream)
@@ -961,6 +1071,28 @@ static void uvc_video_stats_stop(struct uvc_streaming *stream)
stream->stats.stream.stop_ts = ktime_get();
}
+static s64 uvc_stats_add(struct uvc_stats_time *s, const ktime_t a,
+ const ktime_t b)
+{
+ ktime_t delta;
+ u64 duration;
+
+ delta = ktime_sub(b, a);
+ duration = ktime_to_ns(delta);
+
+ s->qty++;
+ s->duration += duration;
+ s->duration2 += duration * duration;
+
+ if (duration < s->min)
+ s->min = duration;
+
+ if (duration > s->max)
+ s->max = duration;
+
+ return duration;
+}
+
/* ------------------------------------------------------------------------
* Video codecs
*/
@@ -1024,6 +1156,9 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
stream->sequence++;
if (stream->sequence)
uvc_video_stats_update(stream);
+
+ /* Update the stream timer each frame */
+ stream->stats.stream.stop_ts = ktime_get();
}
uvc_video_clock_decode(stream, buf, data, len);
@@ -1106,18 +1241,34 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
static void uvc_video_copy_data_work(struct work_struct *work)
{
struct uvc_urb *uvc_urb = container_of(work, struct uvc_urb, work);
+ ktime_t now;
unsigned int i;
int ret;
+ /* Measure decode performance */
+ uvc_urb->decode_start = ktime_get();
+ /* Measure scheduling latency */
+ uvc_stats_add(&uvc_urb->stream->stats.urbstat.latency,
+ uvc_urb->received, uvc_urb->decode_start);
+
for (i = 0; i < uvc_urb->async_operations; i++) {
struct uvc_copy_op *op = &uvc_urb->copy_operations[i];
memcpy(op->dst, op->src, op->len);
+ uvc_urb->stream->stats.stream.bytes += op->len;
/* Release reference taken on this buffer. */
uvc_queue_buffer_release(op->buf);
}
+ now = ktime_get();
+ /* measure 'memcpy time' */
+ uvc_stats_add(&uvc_urb->stream->stats.urbstat.decode,
+ uvc_urb->decode_start, now);
+ /* measure 'full urb processing time' */
+ uvc_stats_add(&uvc_urb->stream->stats.urbstat.urb, uvc_urb->received,
+ now);
+
ret = usb_submit_urb(uvc_urb->urb, GFP_KERNEL);
if (ret < 0)
uvc_printk(KERN_ERR, "Failed to resubmit video URB (%d).\n",
@@ -1507,6 +1658,9 @@ static void uvc_video_complete(struct urb *urb)
unsigned long flags;
int ret;
+ /* Track URB processing performance */
+ uvc_urb->received = ktime_get();
+
switch (urb->status) {
case 0:
break;
@@ -1562,6 +1716,9 @@ static void uvc_video_complete(struct urb *urb)
}
queue_work(stream->async_wq, &uvc_urb->work);
+
+ uvc_stats_add(&uvc_urb->stream->stats.urbstat.header, uvc_urb->received,
+ ktime_get());
}
/*
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 3e3ef1f1daa5..80eeeaf3cd06 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -475,6 +475,14 @@ struct uvc_stats_frame {
u32 scr_stc; /* SCR.STC of the last packet */
};
+struct uvc_stats_time {
+ u64 duration; /* Cumulative total duration between two events */
+ u64 duration2; /* Cumulative total duration^2 between two events */
+ unsigned int qty; /* Number of events represented in the total */
+ unsigned int min; /* Shortest duration */
+ unsigned int max; /* Longest duration */
+};
+
struct uvc_stats_stream {
ktime_t start_ts; /* Stream start timestamp */
ktime_t stop_ts; /* Stream stop timestamp */
@@ -496,6 +504,8 @@ struct uvc_stats_stream {
unsigned int scr_sof; /* STC.SOF of the last packet */
unsigned int min_sof; /* Minimum STC.SOF value */
unsigned int max_sof; /* Maximum STC.SOF value */
+
+ unsigned long bytes; /* Successfully transferred bytes */
};
#define UVC_METADATA_BUF_SIZE 1024
@@ -525,6 +535,8 @@ struct uvc_copy_op {
* @async_operations: counter to indicate the number of copy operations
* @copy_operations: work descriptors for asynchronous copy operations
* @work: work queue entry for asynchronous decode
+ * @received: URB interrupt time stamp
+ * @decode_start: URB processing start time stamp
*/
struct uvc_urb {
struct urb *urb;
@@ -537,6 +549,9 @@ struct uvc_urb {
unsigned int async_operations;
struct uvc_copy_op copy_operations[UVC_MAX_PACKETS];
struct work_struct work;
+
+ ktime_t received;
+ ktime_t decode_start;
};
struct uvc_streaming {
@@ -599,6 +614,12 @@ struct uvc_streaming {
struct {
struct uvc_stats_frame frame;
struct uvc_stats_stream stream;
+ struct uvc_stats_urb {
+ struct uvc_stats_time header;
+ struct uvc_stats_time latency;
+ struct uvc_stats_time decode;
+ struct uvc_stats_time urb;
+ } urbstat;
} stats;
/* Timestamps support. */
--
2.29.2.454.gaff20da3a2-goog