Routing Protocol Multi-core Support
RouterOS v7 can split tasks between multiple processes.
One "main" task starts and stops sub‑tasks and processes data between them. Each sub‑task can allocate "private" memory (accessible only to that task) and "shared" memory (accessible by all route tasks).
The following tasks run in separate processes when multiprocess routing is enabled:
- FIB update.
- Routing Policy configuration.
- Configuration and reporting - handling of the static route configuration, "route print" command, SNMP monitoring, etc.
- BFD protocol handling
- OSPF protocol handling.
- RIP protocol handling.
- ISIS protocol handling.
- EVPN handling.
- PIM-SM.
- LDP protocol handling.
- Fantasy - handles generation of dummy routing entries for testing purposes.
- BGP connection and configuration handling.
- BGP receive (one task per peer or grouped by specific parameters).
- BGP send (one task per peer or grouped by specific parameters).
BGP Sub-Tasks
BGP receive and send can be split into sub‑tasks by specific parameters. For example, you can run input per peer or group all peer inputs and run them in the main process. You control this split with the input.affinity and output.affinity parameters in /routing/bgp/template. On devices with few cores, adjusting affinity values can boost performance because sharing data between tasks is slightly slower than processing the same data within a single task. For example, on single-core or dual-core devices, running input and output in the main or instance process improves performance.
Warning BGP can spawn up to 100 unique processes.
You can monitor all currently used tasks and their allocated private/shared memory with the /routing/stats/process/print command.
Sample Output:
[admin@BGP_MUM] /routing/stats/process> print interval=1
Columns: TASKS, PRIVATE-MEM-BLOCKS, SHARED-MEM-BLOCKS, PSS, RSS, VMS, RETIRED, ID, PID, RPID, PROCESS-TIME, KERNEL-TIME, CUR-BUSY, MAX-BUSY, CUR-CALC, MAX-CALC
# TASKS PRIVATE-M SHARED-M PSS RSS VMS R ID PID R PROCESS- KERNEL-TI CUR- MAX-BUSY CUR- MAX-CALC
0 routing tables 11.8MiB 20.0MiB 19.8MiB 42.2MiB 51.4MiB 7 main 195 0 15s470ms 2s50ms 20ms 1s460ms 20ms 35s120ms
rib
connected networks
1 fib 2816.0KiB 0 8.1MiB 27.4MiB 51.4MiB fib 255 1 5s730ms 7m4s790ms 23s350ms 23s350ms
2 ospf 512.0KiB 0 3151.0KiB 14.6MiB 51.4MiB ospf 260 1 20ms 100ms 20ms 20ms
connected networks
3 fantasy 256.0KiB 0 1898.0KiB 5.8MiB 51.4MiB fantasy 261 1 40ms 60ms 20ms 20ms
4 configuration and reporting 4096.0KiB 512.0KiB 9.2MiB 28.4MiB 51.4MiB static 262 1 3s210ms 40ms 220ms 220ms
5 rip 512.0KiB 0 3151.0KiB 14.6MiB 51.4MiB rip 259 1 50ms 90ms 20ms 20ms
connected networks
6 routing policy configuration 768.0KiB 768.0KiB 2250.0KiB 6.2MiB 51.4MiB policy 256 1 70ms 50ms 20ms 20ms
7 BGP service 768.0KiB 0 3359.0KiB 14.9MiB 51.4MiB bgp 257 1 4s260ms 8s50ms 30ms 30ms
connected networks
8 BFD service 512.0KiB 0 3151.0KiB 14.6MiB 51.4MiB 12 258 1 80ms 40ms 20ms 20ms
connected networks
9 BGP Input 10.155.101.232 8.2MiB 6.8MiB 17.0MiB 39.1MiB 51.4MiB 20 270 1 24s880ms 3s60ms 18s550ms 18s550ms
BGP Output 10.155.101.232
10 Global memory 256.0KiB global 0 0
Routing Table Update Mechanism
The following illustration explains, in a more user‑friendly way, how the routing table update mechanism works.
Routing protocols continuously loop through the following procedures:
- The "main" process waits for updates from other sub‑tasks (1).
- "main" starts calculating new routes (2–4) if:
- an update from a sub‑task is received;
- the protocol has not published all routes;
- the configuration or link state has changed.
- During new route calculation (5), the following events occur:
- all received updates are applied to the route;
- gateway reachability is determined;
- recursive routes are resolved;
- The "publish" event runs, publishing "current" routes. During this phase, "current" routes do not change, but protocols can still receive and send updates (6).
- Perform cleanup and free unused memory (7). At this step, anything no longer used in the new "current" table is removed (routes, attributes, etc.).
Consider "updated" and "current" as two copies of the routing table. The "current" table (2) is used at the moment, while "updated" (1) is the table of candidate routes to be published in the next publish event (3 and 4). This method prevents protocols from filling memory with buffered updates while the "main" process performs "publish". Instead, protocols send the newest updates directly to the main process, which then copies the new updates into the "updated" table. OSPF is slightly more complicated: it internally has a similar process to select current OSPF routes, which are then sent to the "main" for further processing.