graphstats: Add new helper script that generates graphs of MCU load

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

scripts/graphstats.py

@@ -0,0 +1,85 @@
+#!/usr/bin/env python
+# Script to parse a logging file, extract the stats, and graph them
+#
+# Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import optparse, datetime
+import matplotlib.pyplot as plt, matplotlib.dates as mdates
+
+MAXBANDWIDTH=25000.
+MAXBUFFER=5.
+
+def parse_log(logname):
+    f = open(logname, 'rb')
+    out = []
+    for line in f:
+        parts = line.split()
+        if not parts or parts[0] != 'INFO:root:Stats':
+            #if parts and parts[0] == 'INFO:root:shutdown:':
+            #    break
+            continue
+        keyparts = dict(p.split('=', 1) for p in parts[2:])
+        keyparts['#sampletime'] = float(parts[1][:-1])
+        out.append(keyparts)
+    f.close()
+    return out
+
+def plot_mcu(data, maxbw, outname):
+    # Generate data for plot
+    basetime = lasttime = data[0]['#sampletime']
+    lastbw = float(data[0]['bytes_write']) + float(data[0]['bytes_retransmit'])
+    times = []
+    bwdeltas = []
+    loads = []
+    hostbuffers = []
+    for d in data:
+        st = d['#sampletime']
+        timedelta = st - lasttime
+        if timedelta <= 0.:
+            continue
+        bw = float(d['bytes_write']) + float(d['bytes_retransmit'])
+        load = float(d['mcu_task_avg']) + 3*float(d['mcu_task_stddev'])
+        if st - basetime < 15.:
+            load = 0.
+        pt = float(d['print_time'])
+        hb = float(d['buffer_time'])
+        if pt <= 2*MAXBUFFER or hb >= MAXBUFFER:
+            hb = 0.
+        else:
+            hb = 100. * (MAXBUFFER - hb) / MAXBUFFER
+        hostbuffers.append(hb)
+        times.append(datetime.datetime.utcfromtimestamp(st))
+        bwdeltas.append(100. * (bw - lastbw) / (maxbw * timedelta))
+        loads.append(100. * load / .001)
+        lasttime = st
+        lastbw = bw
+
+    # Build plot
+    fig, ax1 = plt.subplots()
+    ax1.set_title("MCU bandwidth and load utilization")
+    ax1.set_xlabel('Time (UTC)')
+    ax1.set_ylabel('Usage (%)')
+    ax1.plot_date(times, loads, 'r', label='MCU load')
+    ax1.plot_date(times, bwdeltas, 'g', label='Bandwidth')
+    #ax1.plot_date(times, hostbuffers, 'c', label='Host buffer')
+    ax1.legend()
+    ax1.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M'))
+    #plt.gcf().autofmt_xdate()
+    ax1.grid(True)
+    plt.savefig(outname)
+
+def main():
+    usage = "%prog [options] <logfile> <outname>"
+    opts = optparse.OptionParser(usage)
+    options, args = opts.parse_args()
+    if len(args) != 2:
+        opts.error("Incorrect number of arguments")
+    logname, outname = args
+    data = parse_log(logname)
+    if not data:
+        return
+    plot_mcu(data, MAXBANDWIDTH, outname)
+
+if __name__ == '__main__':
+    main()