diff --git a/RELEASE_NOTES.rst b/RELEASE_NOTES.rst
index e6fc5e4e1..fa8a83f58 100644
--- a/RELEASE_NOTES.rst
+++ b/RELEASE_NOTES.rst
@@ -38,6 +38,11 @@ Release notes
 * Controllers are now named ``aqctl_XXX`` instead of ``XXX_controller``.
 * In the device database, the "comm" device has been folded into the "core" device.
   Move the "host" argument into the "core" device, and remove the "comm" device.
+* The core device log now contains important information about events such as
+  RTIO collisions. A new controller ``aqctl_corelog`` must be running to forward
+  those logs to the master. See the example device databases to see how to
+  instantiate this controller. Using ``artiq_session`` ensures that a controller
+  manager is running simultaneously with the master.
 
 
 2.3
diff --git a/artiq/examples/drtio/device_db.py b/artiq/examples/drtio/device_db.py
index 2de6862c8..bf64b6df9 100644
--- a/artiq/examples/drtio/device_db.py
+++ b/artiq/examples/drtio/device_db.py
@@ -2,12 +2,20 @@
 # The RTIO channel numbers here are for NIST CLOCK on KC705.
 # The list of devices here is not exhaustive.
 
+core_addr = "kc705.lab.m-labs.hk"
+
 device_db = {
     "core": {
         "type": "local",
         "module": "artiq.coredevice.core",
         "class": "Core",
-        "arguments": {"host": "kc705.lab.m-labs.hk", "ref_period": 2e-9}
+        "arguments": {"host": core_addr, "ref_period": 2e-9}
+    },
+    "core_log": {
+        "type": "controller",
+        "host": "::1",
+        "port": 1068,
+        "command": "aqctl_corelog -p {port} --bind {bind} " + core_addr
     },
     "core_cache": {
         "type": "local",
diff --git a/artiq/examples/master/device_db.py b/artiq/examples/master/device_db.py
index b53f53734..0af7c28c1 100644
--- a/artiq/examples/master/device_db.py
+++ b/artiq/examples/master/device_db.py
@@ -2,12 +2,20 @@
 # The RTIO channel numbers here are for NIST CLOCK on KC705.
 # The list of devices here is not exhaustive.
 
+core_addr = "kc705.lab.m-labs.hk"
+
 device_db = {
     "core": {
         "type": "local",
         "module": "artiq.coredevice.core",
         "class": "Core",
-        "arguments": {"host": "kc705.lab.m-labs.hk", "ref_period": 1e-9}
+        "arguments": {"host": core_addr, "ref_period": 1e-9}
+    },
+    "core_log": {
+        "type": "controller",
+        "host": "::1",
+        "port": 1068,
+        "command": "aqctl_corelog -p {port} --bind {bind} " + core_addr
     },
     "core_cache": {
         "type": "local",
diff --git a/artiq/examples/phaser/device_db.py b/artiq/examples/phaser/device_db.py
index d1397efb9..e487e0711 100644
--- a/artiq/examples/phaser/device_db.py
+++ b/artiq/examples/phaser/device_db.py
@@ -1,14 +1,19 @@
 # The RTIO channel numbers here are for Phaser on KC705.
 
+core_addr = "kc705aux.lab.m-labs.hk"
+
 device_db = {
     "core": {
         "type": "local",
         "module": "artiq.coredevice.core",
         "class": "Core",
-        "arguments": {
-            "host": "kc705aux.lab.m-labs.hk",
-            "ref_period": 5e-9/6
-        }
+        "arguments": {"host": core_addr, "ref_period": 5e-9/6}
+    },
+    "core_log": {
+        "type": "controller",
+        "host": "::1",
+        "port": 1068,
+        "command": "aqctl_corelog -p {port} --bind {bind} " + core_addr
     },
     "core_cache": {
         "type": "local",
diff --git a/artiq/frontend/aqctl_corelog.py b/artiq/frontend/aqctl_corelog.py
new file mode 100755
index 000000000..fbff64691
--- /dev/null
+++ b/artiq/frontend/aqctl_corelog.py
@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+
+import argparse
+import asyncio
+
+from artiq.protocols.pc_rpc import Server
+from artiq.tools import *
+
+
+def get_argparser():
+    parser = argparse.ArgumentParser(
+        description="ARTIQ controller for core device logs")
+    simple_network_args(parser, 1068)
+    parser.add_argument("core_addr",
+                        help="hostname or IP address of the core device")
+    verbosity_args(parser)
+    return parser
+
+
+class PingTarget:
+    def ping(self):
+        return True
+
+
+async def get_logs(host):
+    while True:
+        print("TODO: not implemented. host:", host)
+        await asyncio.sleep(2)
+
+
+def main():
+    args = get_argparser().parse_args()
+    init_logger(args)
+
+    loop = asyncio.get_event_loop()
+    try:
+        get_logs_task = asyncio.ensure_future(get_logs(args.core_addr))
+        try:
+            server = Server({"corelog": PingTarget()}, None, True)
+            loop.run_until_complete(server.start(bind_address_from_args(args), args.port))
+            try:
+                loop.run_until_complete(server.wait_terminate())
+            finally:
+                loop.run_until_complete(server.stop())
+        finally:
+            get_logs_task.cancel()
+            try:
+                loop.run_until_complete(get_logs_task)
+            except asyncio.CancelledError:
+                pass
+    finally:
+        loop.close()
+
+if __name__ == "__main__":
+    main()
diff --git a/doc/manual/default_network_ports.rst b/doc/manual/default_network_ports.rst
index e3e669019..188270095 100644
--- a/doc/manual/default_network_ports.rst
+++ b/doc/manual/default_network_ports.rst
@@ -1,37 +1,38 @@
 Default network ports
 =====================
 
-+--------------------------+--------------+
-| Component                | Default port |
-+==========================+==============+
-| Core device (management) | 1380         |
-+--------------------------+--------------+
-| Core device (main)       | 1381         |
-+--------------------------+--------------+
-| Core device (analyzer)   | 1382         |
-+--------------------------+--------------+
-| Core device (mon/inj)    | 1383         |
-+--------------------------+--------------+
-| Master (logging input)   | 1066         |
-+--------------------------+--------------+
-| Master (broadcasts)      | 1067         |
-+--------------------------+--------------+
-| InfluxDB bridge          | 3248         |
-+--------------------------+--------------+
-| Controller manager       | 3249         |
-+--------------------------+--------------+
-| Master (notifications)   | 3250         |
-+--------------------------+--------------+
-| Master (control)         | 3251         |
-+--------------------------+--------------+
-| PDQ2                     | 3252         |
-+--------------------------+--------------+
-| LDA                      | 3253         |
-+--------------------------+--------------+
-| Novatech 409B            | 3254         |
-+--------------------------+--------------+
-| Thorlabs T-Cube          | 3255         |
-+--------------------------+--------------+
-| Korad KA3005P            | 3256         |
-+--------------------------+--------------+
-
++--------------------------------+--------------+
+| Component                      | Default port |
++================================+==============+
+| Core device (management)       | 1380         |
++--------------------------------+--------------+
+| Core device (main)             | 1381         |
++--------------------------------+--------------+
+| Core device (analyzer)         | 1382         |
++--------------------------------+--------------+
+| Core device (mon/inj)          | 1383         |
++--------------------------------+--------------+
+| Master (logging input)         | 1066         |
++--------------------------------+--------------+
+| Master (broadcasts)            | 1067         |
++--------------------------------+--------------|
+| Core device logging controller | 1068         |
++--------------------------------+--------------+
+| InfluxDB bridge                | 3248         |
++--------------------------------+--------------+
+| Controller manager             | 3249         |
++--------------------------------+--------------+
+| Master (notifications)         | 3250         |
++--------------------------------+--------------+
+| Master (control)               | 3251         |
++--------------------------------+--------------+
+| PDQ2                           | 3252         |
++--------------------------------+--------------+
+| LDA                            | 3253         |
++--------------------------------+--------------+
+| Novatech 409B                  | 3254         |
++--------------------------------+--------------+
+| Thorlabs T-Cube                | 3255         |
++--------------------------------+--------------+
+| Korad KA3005P                  | 3256         |
++--------------------------------+--------------+