Batching and Turbo Mode

Concept

Batching can be used to decrease the amount of communication overhead associated with the transmission and (in the case of reliable communication) acknowledgement of small samples, in order to increase throughput.

It specifies and configures the mechanism that allows Connext to collect multiple user data samples to be sent in a single network packet, to take advantage of the efficiency of sending larger packets and thus increase effective throughput.

Batching can be used to increase effective throughput dramatically for small data samples. Throughput for small samples (size < 2048 bytes) is typically limited by CPU capacity and not by network bandwidth. Batching many smaller samples to be sent in a single large packet will increase network utilization and thus throughput in terms of samples per second.

Turbo Mode is an experimental feature that uses an intelligent algorithm that adjusts the number of bytes in a batch at runtime according to current system conditions, such as write speed (or write frequency) and sample size. This intelligence is what gives it the ability to increase throughput at high message rates and avoid negatively impacting message latency at low message rates

Example Description

This example shows the differences between batching and turbo mode. Both options will send batches. This means that instead of sending each sample out on the wire with its own header, the middleware will store the data in a batch until it is full and then will send the entire batch as one data packet.

The publisher application has two configurations (two different profiles):

• The first one uses the Batching QoS setting. We have included a package capture you can analyze using wireshark.

  batchin_10_samples.pcap file package no. 98.

• The second one uses Turbo Mode. We have included a package capture you can analyze using wireshark.

  turbo_mode.pcap file package no. 76.

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