2.18.1 Compilation build time

Modern software applications can comprise many thousands of source code files. These files can take a considerable amount of time to compile. The many different techniques that the ARM compilation tools use to optimize for small code size and high performance can also increase build time.

When you invoke the compiler, the following steps occur:

  1. The compiler loads and begins to execute.

  2. The compiler tries to obtain a license.

  3. The compiler compiles your code.

Loading and beginning to execute the compiler normally takes a fixed period of time.

The time taken to obtain a license does not generally vary if a license is available. However, if a floating license is being used, the time taken to obtain a license depends on network traffic and whether or not a license is free on the server. In most cases, rather than terminate with error if a license is not immediately available, the compiler waits for a license to become available.

The process of obtaining a floating license is more involved than obtaining a node-locked license. With a node-locked license, the compiler only has to parse the file to check that there is a valid license. With a floating license, the compiler has to check where the license is, send a message through the TCP/IP stacks over the network to the server, then wait for a response. When the compiler receives the response, it then has to check whether or not it has been granted a license. When the compilation is complete, the license has to be returned back to the server.

Floating licenses provide flexibility, but at the cost of speed. If speed is your priority, consider obtaining node-locked licenses for your build machines, or some node-locked licenses locked to USB network cards that can be moved between machines as required.

Setting the environment variable TCP_NODELAY to 1 improves FlexNet license server system performance when processing license requests. However, you must use this with caution, because it might cause an increase in network traffic.

The time taken to compile your code depends on the size and complexity of the file being compiled. Compiling a small number of large files might be quicker than compiling a larger number of small files. This is because the longer compilation time per file might be offset by the smaller amount of time spent loading and unloading the compiler and obtaining licenses.

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