Native Thread Pools

This section lists the directives for controlling the size of the native kernel thread pool. You can also control the native thread pool by setting the system variables NSCP_POOL_STACKSIZE, NSCP_POOL_THREADMAX, and NSCP_POOL_WORKQUEUEMAX. If you have set these values as environment variables and also in magnus.conf, the environment variable values will take precedence.

The native pool on UNIX is normally not engaged, as all threads are OS-level threads. Using native pools on UNIX may introduce a small performance overhead as they’ll require an additional context switch; however, they can be used to localize the jvm.stickyAttach effect or for other purposes, such as resource control and management or to emulate single-threaded behavior for plug-ins.

On Windows, the default native pool is always being used and Sun Java System Web Server uses fibers (user-scheduled threads) for initial request processing. Using custom additional pools on Windows introduces no additional overhead.

The directives are:

• NativePoolStackSize

• NativePoolMaxThreads

• NativePoolMinThreads

• NativePoolQueueSize

NativePoolStackSize

Determines the stack size of each thread in the native (kernel) thread pool.

Default

0

NativePoolMaxThreads

Determines the maximum number of threads in the native (kernel) thread pool.

NativePoolMinThreads

Determines the minimum number of threads in the native (kernel) thread pool.

Default

1

NativePoolQueueSize

Determines the number of threads that can wait in the queue for the thread pool. If all threads in the pool are busy, then the next request-handling thread that needs to use a thread in the native pool must wait in the queue. If the queue is full, the next request-handling thread that tries to get in the queue is rejected, with the result that it returns a busy response to the client. It is then free to handle another incoming request instead of being tied up waiting in the queue.

Default

0