Question

Currently i am in a process of developing a application which can work in a multi threaded mode. As part of testing on my local machine (Intel Core I5) i tested with 4 threads. But now want to release the code for intense(regression) testing, so there any hard rule by which we can decide the number of threads to be created for processing.

I am not using any web or App server, instead i have written my logic to receive the request and then process it. Now During the processing, i receive the request on main Thread, and then i submit the call to ExecuterService where i need to decide the number of threads, then i process the request and each thread is again capable of returning the response.

I need to configure an optimum number of thread. I am trying to deploy my application on 16-Core, with 40GB Memory linux machine.

Thanks

Answer 1

In theory, the optimal number of threads is equal to the number of cores in your machine.
In practice, many operations are waiting for memory, IO, network or disk.

Try to execute only a single thread. If the CPU core load is 25% – you can try to create (4 x the number of cores in your machine) threads.

Note that increasing the number of threads will effect the time each thread will wait for network/disk/memory/IO, so it is somewhat more complex.

The best thing you can do is benchmark: Measure how much time it would take to complete 1,000,000 simulated requests – given different number of threads.