Use Leshan Client to launch thousands LWM2M clients in the same VM.

Currently by default a Leshan client uses 10 threads :

• 1 UDP sender (from element-connector)
• 1 UDP receiver (from element-connector)
• 2 Deduplicator (from californium)
• 1 Coap Server (from californium)
• 1 DTLS sender (from scandium)
• 1 DTLS receiver (from scandium)
• 1 DTLS retransmit (from scandium)
• 1 DTLS connectionHandler (from scandium)
• 1 registration engine (from leshan)

We can reduce it by removing 3(UDP+1deduplicator) or 5(DTLS+1deduplicator) threads if your are using only UDP or only DTLS. To do that LeshanClientBuilder.disableUnsecuredEndpoint() or disableSecuredEndpoint()…

But this is still 5 or 7 threads by clients, if you want to create a simulator which would run thousands of clients that’s means thousands of threads there is no way this was a good design…

I suppose we should change the code a bit to be able to use only one thread pool executor for all the clients. Currently this is partially done in californium/scandium, you can set a common executor for DTLSConnectionHandler and CoAP server so you will save 2 more thread by clients.

With Leshan 1.0.0-M5, this will looks like this :

final ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
builder.setEndpointFactory(new EndpointFactory() {
    @Override
    public CoapEndpoint createUnsecuredEndpoint(InetSocketAddress address, NetworkConfig coapConfig,
            ObservationStore store) {
         return new CoapEndpoint(address, coapConfig);
    }
    @Override
    public CoapEndpoint createSecuredEndpoint(DtlsConnectorConfig dtlsConfig, NetworkConfig coapConfig,
            ObservationStore store) {
        DTLSConnector dtlsConnector = new DTLSConnector(dtlsConfig);
        dtlsConnector.setExecutor(new StripedExecutorService(executor));

        return new CoapEndpoint(dtlsConnector, coapConfig, null, null);
    }
});
client = builder.build();
client.getCoapServer().setExecutor(executor);

[sbernard31]

@nkvaratskhelia see #744

[sbernard31]

#794 is now integrated in master.

You can now use :

ScheduledExecutorService sharedExecutor = Executors.newScheduledThreadPool(100,
        new NamedThreadFactory("shared executor"));

LeshanClient[] clients = new LeshanClient[3000];
for (int i = 0; i < clients.length; i++) {
    LeshanClientBuilder builder = new LeshanClientBuilder("myclient" + i);
    builder.setSharedExecutor(sharedExecutor);
    clients[i] = builder.build();
}