Add benchmark script

.gitignore

@@ -2,3 +2,4 @@
 __pycache__
 resources
 *.kate-swp
+benchmark.*.txt

benchmark.sh

@@ -0,0 +1,89 @@
+#!/bin/sh
+set -eu
+
+width=1920
+height=1080
+fps=60
+timeout=180
+video_url="https://google.github.io/mediapipe/images/selfie_segmentation_web.mp4"
+
+for ffmpeg in ffmpeg avconv ""; do
+    test -n "$ffmpeg" || {
+        echo "This script needs ffmpeg or avconv."
+        exit 1
+    }
+    command -v "$ffmpeg" >/dev/null && break || :
+done
+
+# get sudo password and keep it active
+sudo -v
+( while sleep 1; do sudo -v; done; ) &
+pids="$!"
+
+# create file for test video
+video="$(mktemp)"
+
+# registister cleanup function
+cleanup() {
+    rm -f -- "$video"
+    kill $pids; wait
+    sudo -- $SHELL -c 'modprobe -r v4l2loopback; modprobe v4l2loopback'
+}
+trap cleanup EXIT
+
+# create the necessary v4l2loopback devices
+sudo -- $SHELL -s <<EOF
+modprobe -r v4l2loopback
+modprobe v4l2loopback devices=2 exclusive_caps=1,1 video_nr=99,100
+EOF
+
+# download video and loop it to /dev/video99
+wget -qO "$video" "$video_url"
+"$ffmpeg" -hide_banner -loglevel quiet -hwaccel auto \
+    -re -stream_loop -1 -i "$video" \
+    -vf scale="$width:$height" -r "$fps" \
+    -f v4l2 -an -vcodec rawvideo -pix_fmt yuyv422 /dev/video99 &
+pids="$pids $!"
+sleep 3
+
+git_head="$(git rev-parse HEAD)"
+{
+echo "${width}x${height}@$fps for $timeout seconds"
+test $# -eq 0 || echo "extra arguments: $*"
+echo "HEAD: $git_head"; echo
+
+# system information
+uname -srvmo
+sed -n 's/^model name\s*:\s*//p' /proc/cpuinfo | sort | uniq -c; echo
+
+# python information
+python3 -c '
+import importlib.metadata, sys
+venv = (hasattr(sys, "real_prefix") or
+    (hasattr(sys, "base_prefix") and sys.base_prefix != sys.prefix))
+print("python", sys.version)
+print("virtualenv", venv)
+print()
+for module in sys.argv[1:]:
+    try:
+        print(module, importlib.metadata.version(module))
+    except importlib.metadata.PackageNotFoundError:
+        print(module, "not found")
+' $(sed -rn 's/^([A-Z0-9][A-Z0-9._-]*[A-Z0-9]).*/\1/pi' requirements.txt); echo
+
+# run fake.py for specified timeout and gather statistics
+export PYTHONUNBUFFERED=yes
+timeout --foreground --preserve-status -s QUIT "$timeout" \
+    ./fake.py -w /dev/video99 -v /dev/video100 \
+        -W "$width" -H "$height" -F "$fps" --no-ondemand "$@" |
+    stdbuf -oL tr '\r' '\n' |
+    python3 -c '
+import sys, statistics
+fps = []
+for line in sys.stdin:
+    if line.startswith("FPS:"):
+        fps.append(float(line.split(":")[-1].strip()))
+        print(fps[-1], end="\r", file=sys.stderr)
+print("avg %.2f, stdev %.2f" %(statistics.mean(fps), statistics.stdev(fps)))
+'
+} | tee "benchmark.$git_head.txt"