9.1. Latency Benchmarks¶

Latency measurements are provided for two different environments:

Xeon – End-to-End latency measured on high-performance Xeon machines in a dedicated network using the RTI Connext DDS Performance Test tool.
Raspberry Pi – Round-trip latencies measured on stock Raspberry Pi’s in a dedicated network using the RTI Connext DDS Performance Test tool.

The latency is measured by sending one PING sample and wait for the Echoer to return the PONG sample. The sender records the time it took to receive the PONG sample and divides the result by 2. The test is repeated a number of times for each size. Note that the end-to-end latency is measured.

Interpretation of the measurements (all numbers are reported in micro-seconds):

Length - The size of the DDS sample payload (UDP overhead is _not_ included) in bytes.
Ave - Average latency
Std - Standard deviation
Min - The minimum latency
Max - The maximum latency
50% - The 50th percentile latency
90% - The 90th percentile latency
99% - The 99th percentile latency
99.99% - The 99.99th percentile latency

9.1.1. Xeon¶

The end-to-end latency is measured between two identical machines using the test configuration below and running the RTI Connext DDS Performance Test tool.

The test environment consists of:

x86_64 CentOS Linux release 7.1.1503
RTI Perftest 3.0
Switch Configuration: D-Link DXS-3350 SR:
- 176Gbps Switching Capacity
- Dual 10-Gig stacking ports and optional 10-Gig uplinks
- Stacks up to 8 units per stack
- 4MB (Packet Buffer Size)
- 48 x 10/100/1000BASE-T ports
Machine:
- Intel I350 Gigabit NIC
- Intel Core i7 CPU:
  - 12MB cache
  - 6 Cores (12 threads)
  - 3.33 GHz CPU speed
- 12GB memory

9.1.1.1. C++ Best Effort Keyed 1 Gbps¶

Length	Ave (us)	Std	Min (us)	Max (us)	50%	90%	99%	99.99%
32	25	0.6	23	83	25	25	26	28
64	25	0.5	24	295	25	25	26	28
128	26	0.5	25	80	26	27	28	30
256	30	0.7	28	316	29	30	31	33
1024	44	0.6	43	334	44	44	46	49
4096	76	1.0	75	360	77	77	78	81
8192	114	0.8	112	363	114	114	115	118
63000	605	1.1	603	659	605	606	608	623

9.1.1.2. C++ Best Effort Unkeyed 1 Gbps¶

Length	Ave (us)	Std	Min (us)	Max (us)	50%	90%	99%	99.99%
32	24	0.5	23	299	24	24	25	27
64	25	0.6	23	308	25	25	26	28
128	26	0.6	24	276	26	26	27	29
256	28	0.6	27	316	28	28	30	32
1024	43	0.5	42	312	43	43	44	47
4096	76	0.8	74	434	77	77	78	81
8192	113	0.7	112	360	113	114	115	118
63000	604	1.3	603	790	604	606	607	624

9.1.1.3. C++ Reliable Keyed 1 Gbps¶

Length	Ave (us)	Std	Min (us)	Max (us)	50%	90%	99%	99.99%
32	27	1.4	25	309	27	30	31	33
64	28	1.9	26	590	27	31	33	35
128	30	1.3	27	312	29	32	33	35
256	33	1.3	29	313	32	35	36	39
1024	47	1.3	45	527	47	49	50	54
4096	80	1.8	78	594	80	80	82	86
8192	117	1.8	115	605	117	119	120	123
63000	610	1.3	605	667	610	612	613	628

9.1.1.4. C++ Reliable Unkeyed 1 Gbps¶

Length	Ave (us)	Std	Min (us)	Max (us)	50%	90%	99%	99.99%
32	27	1.4	25	559	26	29	30	33
64	28	1.5	25	322	26	31	32	34
128	29	1.5	25	317	29	31	32	35
256	32	1.3	30	581	32	34	35	37
1024	47	1.2	45	342	46	49	50	52
4096	80	1.3	78	356	79	81	83	85
8192	117	1.5	115	546	116	119	120	123
63000	609	1.2	607	662	609	611	613	625

9.1.2. Raspberry Pi¶

The end-to-end latency is measured between two identical machines using the test configuration below and running the RTI Connext DDS Performance Test tool.

The test environment consists of:

2 x Raspberry Pi 4 Model B
1 Gbps network

9.1.2.1. C++ Best Effort Keyed 1 Gbps¶

Length	Ave (us)	Std	Min (us)	Max (us)	50%	90%	99%	99.99%
32	67	5.6	62	274	65	78	80	160
64	68	5.7	63	223	66	79	81	162
128	69	5.5	64	225	67	80	82	160
256	71	5.5	67	232	70	83	85	158
512	77	5.7	72	245	75	88	90	165
1024	89	7.2	83	236	86	100	103	178
8192	182	8.6	176	635	181	183	205	405
63000	865	42.6	849	2138	860	872	894	2039

9.1.2.2. C++ Best Effort Unkeyed 1 Gbps¶

Length	Ave (us)	Std	Min (us)	Max (us)	50%	90%	99%	99.99%
32	64	4.5	61	220	64	65	78	159
64	67	5.3	61	214	65	77	80	151
128	68	7.1	63	2093	66	79	82	155
256	71	5.9	65	262	69	81	84	172
512	76	5.6	71	221	74	87	91	162
1024	88	7.3	81	256	85	99	106	176
8192	181	11.5	175	1395	180	182	210	412
63000	864	43.0	848	2698	860	871	893	2149

9.1.2.3. C++ Reliable Keyed 1 Gbps¶

Length	Ave (us)	Std	Min (us)	Max (us)	50%	90%	99%	99.99%
32	87	5.5	79	290	86	92	101	215
64	88	5.1	81	259	86	92	105	196
128	89	4.9	81	242	88	93	105	188
256	91	5.0	84	274	90	96	109	211
512	96	5.2	89	316	95	101	113	223
1024	109	7.4	101	279	106	120	131	228
8192	183	9.8	176	518	181	189	211	432
63000	870	45.2	849	2494	865	881	904	2363

9.1.2.4. C++ Reliable Unkeyed 1 Gbps¶

Length	Ave (us)	Std	Min (us)	Max (us)	50%	90%	99%	99.99%
32	85	5.6	78	276	83	91	102	200
64	87	5.3	79	267	86	92	103	185
128	88	5.1	81	270	87	93	103	215
256	90	7.3	82	2149	89	95	107	218
512	96	6.2	88	1713	94	100	114	180
1024	108	9.8	101	2157	105	118	131	229
8192	184	11.0	176	478	181	190	222	420
63000	868	43.5	849	2234	863	880	905	2040