; This is adapted from a benchmark written by John Ellis and Pete Kovac
; of Post Communications.
; It was modified by Hans Boehm of Silicon Graphics.
; It was translated into Scheme by William D Clinger of Northeastern Univ;
; the Scheme version uses (RUN-BENCHMARK <string> <thunk>)
; Last modified 30 May 1997.
;
; This is no substitute for real applications. No actual application
; is likely to behave in exactly this way. However, this benchmark was
; designed to be more representative of real applications than other
; Java GC benchmarks of which we are aware.
; It attempts to model those properties of allocation requests that
; are important to current GC techniques.
; It is designed to be used either to obtain a single overall performance
; number, or to give a more detailed estimate of how collector
; performance varies with object lifetimes. It prints the time
; required to allocate and collect balanced binary trees of various
; sizes. Smaller trees result in shorter object lifetimes. Each cycle
; allocates roughly the same amount of memory.
; Two data structures are kept around during the entire process, so
; that the measured performance is representative of applications
; that maintain some live in-memory data. One of these is a tree
; containing many pointers. The other is a large array containing
; double precision floating point numbers. Both should be of comparable
; size.
;
; The results are only really meaningful together with a specification
; of how much memory was used. It is possible to trade memory for
; better time performance. This benchmark should be run in a 32 MB
; heap, though we don't currently know how to enforce that uniformly.
; In the Java version, this routine prints the heap size and the amount
; of free memory. There is no portable way to do this in Scheme; each
; implementation needs its own version.
(library (r6rs-benchmarks gcbench)
(export main)
(import (r6rs) (r6rs arithmetic flonums) (r6rs-benchmarks))
(define (run-benchmark2 name thunk)
(display name)
(newline)
(thunk))
(define (PrintDiagnostics)
(display " Total memory available= ???????? bytes")
(display " Free memory= ???????? bytes")
(newline))
(define (gcbench kStretchTreeDepth)
; Nodes used by a tree of a given size
(define (TreeSize i)
(- (expt 2 (+ i 1)) 1))
; Number of iterations to use for a given tree depth
(define (NumIters i)
(quotient (* 2 (TreeSize kStretchTreeDepth))
(TreeSize i)))
; Parameters are determined by kStretchTreeDepth.
; In Boehm's version the parameters were fixed as follows:
; public static final int kStretchTreeDepth = 18; // about 16Mb
; public static final int kLongLivedTreeDepth = 16; // about 4Mb
; public static final int kArraySize = 500000; // about 4Mb
; public static final int kMinTreeDepth = 4;
; public static final int kMaxTreeDepth = 16;
; In Larceny the storage numbers above would be 12 Mby, 3 Mby, 6 Mby.
(let* ((kLongLivedTreeDepth (- kStretchTreeDepth 2))
(kArraySize (* 4 (TreeSize kLongLivedTreeDepth)))
(kMinTreeDepth 4)
(kMaxTreeDepth kLongLivedTreeDepth))
; Elements 3 and 4 of the allocated vectors are useless.
(let* ((make-empty-node (lambda () (make-vector 4 0)))
(make-node
(lambda (l r)
(let ((v (make-empty-node)))
(vector-set! v 0 l)
(vector-set! v 1 r)
v)))
(node.left (lambda (node) (vector-ref node 0)))
(node.right (lambda (node) (vector-ref node 1)))
(node.left-set! (lambda (node x) (vector-set! node 0 x)))
(node.right-set! (lambda (node x) (vector-set! node 1 x))))
; Build tree top down, assigning to older objects.
(define (Populate iDepth thisNode)
(if (<= iDepth 0)
#f
(let ((iDepth (- iDepth 1)))
(node.left-set! thisNode (make-empty-node))
(node.right-set! thisNode (make-empty-node))
(Populate iDepth (node.left thisNode))
(Populate iDepth (node.right thisNode)))))
; Build tree bottom-up
(define (MakeTree iDepth)
(if (<= iDepth 0)
(make-empty-node)
(make-node (MakeTree (- iDepth 1))
(MakeTree (- iDepth 1)))))
(define (TimeConstruction depth)
(let ((iNumIters (NumIters depth)))
(display (string-append "Creating "
(number->string iNumIters)
" trees of depth "
(number->string depth)))
(newline)
(run-benchmark2
"GCBench: Top down construction"
(lambda ()
(do ((i 0 (+ i 1)))
((>= i iNumIters))
(Populate depth (make-empty-node)))))
(run-benchmark2
"GCBench: Bottom up construction"
(lambda ()
(do ((i 0 (+ i 1)))
((>= i iNumIters))
(MakeTree depth))))))
(define (main)
(display "Garbage Collector Test")
(newline)
(display (string-append
" Stretching memory with a binary tree of depth "
(number->string kStretchTreeDepth)))
(newline)
(PrintDiagnostics)
(run-benchmark2
"GCBench: Main"
(lambda ()
; Stretch the memory space quickly
(MakeTree kStretchTreeDepth)
; Create a long lived object
(display (string-append
" Creating a long-lived binary tree of depth "
(number->string kLongLivedTreeDepth)))
(newline)
(let ((longLivedTree (make-empty-node)))
(Populate kLongLivedTreeDepth longLivedTree)
; Create long-lived array, filling half of it
(display (string-append
" Creating a long-lived array of "
(number->string kArraySize)
" inexact reals"))
(newline)
(let ((array (make-vector kArraySize 0.0)))
(do ((i 0 (+ i 1)))
((>= i (quotient kArraySize 2)))
(vector-set! array i (/ 1.0 (exact->inexact (+ i 1)))))
(PrintDiagnostics)
(do ((d kMinTreeDepth (+ d 2)))
((> d kMaxTreeDepth))
(TimeConstruction d))
(if (or (eq? longLivedTree '())
(let ((n (min 1000
(- (quotient (vector-length array)
2)
1))))
(not (fl=? (vector-ref array n)
(/ 1.0 (exact->inexact (+ n 1)))))))
(begin (display "Failed") (newline)))
; fake reference to LongLivedTree
; and array
; to keep them from being optimized away
))))
(PrintDiagnostics))
(main))))
(define (main . rest)
(let ((k (if (null? rest) 18 (car rest))))
(display "The garbage collector should touch about ")
(display (expt 2 (- k 13)))
(display " megabytes of heap storage.")
(newline)
(display "The use of more or less memory will skew the results.")
(newline)
(run-benchmark
(string-append "GCBench" (number->string k))
gcbench-iters
(lambda (result) #t)
(lambda (k) (lambda () (gcbench k)))
k))))