PROBLEM========================================================================= Thread creation is an 'heavy' process. Too many thrads hurts performance. SOLUTION======================================================================== thread-pool is a simple library that allows users for asynchronous computation using only a fixed number of threads optimizing overall performance. SAMPLE USAGE=================================================================== CL-USER> (require :thread-pool) CL-USER> (let ((out *standard-output*)) (defun make-lazy-fib (n) (labels ((fib (n) (if (> n 2) (+ (fib (- n 1)) (fib (- n 2))) 1))) (lambda () (format out "~%fib ~a = ~a~%" n (fib n)))))) CL-USER> (defvar *pool* (thread-pool:make-thread-pool 3)) *POOL* CL-USER> (thread-pool:start-pool *pool*) (#<SB-THREAD:THREAD "Anonymous thread" RUNNING {1002B88871}> #<SB-THREAD:THREAD "Anonymous thread" RUNNING {1002B88A71}> #<SB-THREAD:THREAD "Anonymous thread" RUNNING {1002B88C71}>) CL-USER> (let ((out *standard-output*)) (defun make-lazy-fib (n) (flet ((fib (n) (if (> n 2) (+ (fib (- n 1)) (fib (- n 2))) 1))) (lambda () (format out "~%fib ~a = ~a~%" n (fib n)))))) MAKE-LAZY-FIB CL-USER> (progn (thread-pool:add-to-pool *pool* (make-lazy-fib 15)) (thread-pool:add-to-pool *pool* (make-lazy-fib 20)) (thread-pool:add-to-pool *pool* (make-lazy-fib 5)) (thread-pool:add-to-pool *pool* (make-lazy-fib 17)) (thread-pool:add-to-pool *pool* (make-lazy-fib 10)) (thread-pool:add-to-pool *pool* (make-lazy-fib 6))) (#<CLOSURE (LAMBDA #) {10058664E9}>) (#<CLOSURE (LAMBDA #) {10058664E9}> #<CLOSURE (LAMBDA #) {1005867419}>) (#<CLOSURE (LAMBDA #) {10058664E9}> #<CLOSURE (LAMBDA #) {1005867419}> #<CLOSURE (LAMBDA #) {10058709C9}>) fib 15 = 610 (#<CLOSURE (LAMBDA #) {1005867419}> #<CLOSURE (LAMBDA #) {10058709C9}> #<CLOSURE (LAMBDA #) {1005872699}>) (#<CLOSURE (LAMBDA #) {10058709C9}> #<CLOSURE (LAMBDA #) {1005872699}> #<CLOSURE (LAMBDA #) {1005874369}>) (#<CLOSURE (LAMBDA #) {10058709C9}> #<CLOSURE (LAMBDA #) {1005872699}> #<CLOSURE (LAMBDA #) {1005874369}> #<CLOSURE (LAMBDA #) {1005876039}>) fib 5 = 5 fib 20 = 6765 fib 17 = 1597 fib 10 = 55 fib 6 = 8 1