core_analyzer: support uniform VCD time intervals

close #1236

Signed-off-by: Robert Jördens <rj@quartiq.de>

artiq/coredevice/comm_analyzer.py

@@ -501,10 +501,12 @@ def get_message_time(message):
     return getattr(message, "timestamp", message.rtio_counter)
 
 
-def decoded_dump_to_vcd(fileobj, devices, dump):
+def decoded_dump_to_vcd(fileobj, devices, dump, uniform_interval=False):
     vcd_manager = VCDManager(fileobj)
     ref_period = get_ref_period(devices)
+
     if ref_period is not None:
+        if not uniform_interval:
             vcd_manager.set_timescale_ps(ref_period*1e12)
     else:
         logger.warning("unable to determine core device ref_period")
@@ -527,6 +529,12 @@ def decoded_dump_to_vcd(fileobj, devices, dump):
     vcd_log_channels = get_vcd_log_channels(dump.log_channel, messages)
     channel_handlers[dump.log_channel] = LogHandler(
         vcd_manager, vcd_log_channels)
+    if uniform_interval:
+        # RTIO event timestamp in machine units
+        timestamp = vcd_manager.get_channel("timestamp", 64)
+        # RTIO time interval between this and the next timed event
+        # in SI seconds
+        interval = vcd_manager.get_channel("interval", 64)
     slack = vcd_manager.get_channel("rtio_slack", 64)
 
     vcd_manager.set_time(0)
@@ -536,10 +544,17 @@ def decoded_dump_to_vcd(fileobj, devices, dump):
         if start_time:
             break
 
-    for message in messages:
+    t0 = 0
+    for i, message in enumerate(messages):
         if message.channel in channel_handlers:
             t = get_message_time(message) - start_time
             if t >= 0:
+                if uniform_interval:
+                    interval.set_value_double((t - t0)*ref_period)
+                    vcd_manager.set_time(i)
+                    timestamp.set_value("{:064b}".format(t))
+                    t0 = t
+                else:
                     vcd_manager.set_time(t)
             channel_handlers[message.channel].process_message(message)
             if isinstance(message, OutputMessage):

artiq/frontend/artiq_coreanalyzer.py

@@ -20,12 +20,18 @@ def get_argparser():
 
     parser.add_argument("-r", "--read-dump", type=str, default=None,
                         help="read raw dump file instead of accessing device")
-    parser.add_argument("-p", "--print-decoded", default=False, action="store_true",
-                        help="print raw decoded messages")
+    parser.add_argument("-p", "--print-decoded", default=False,
+                        action="store_true", help="print raw decoded messages")
     parser.add_argument("-w", "--write-vcd", type=str, default=None,
                         help="format and write contents to VCD file")
     parser.add_argument("-d", "--write-dump", type=str, default=None,
                         help="write raw dump file")
+
+    parser.add_argument("-u", "--vcd-uniform-interval", action="store_true",
+                        help="emit uniform time intervals between timed VCD "
+                             "events and show RTIO event interval (in SI "
+                             "seconds) and timestamp (in machine units) as "
+                             "separate VCD channels")
     return parser
 
 
@@ -54,7 +60,8 @@ def main():
     if args.write_vcd:
         with open(args.write_vcd, "w") as f:
             decoded_dump_to_vcd(f, device_mgr.get_device_db(),
-                                decoded_dump)
+                                decoded_dump,
+                                uniform_interval=args.vcd_uniform_interval)
     if args.write_dump:
         with open(args.write_dump, "wb") as f:
             f.write(dump)