performance measurements
Each table row shows performance measurements for this C gcc program with a particular command-line input value N.
| N | CPU secs | Elapsed secs | Memory KB | Code B | ≈ CPU Load |
|---|---|---|---|---|---|
| 12 | 0.00 | 0.01 | ? | 594 | 0% 0% 0% 50% |
| 16 | 0.13 | 0.13 | ? | 594 | 0% 0% 7% 100% |
| 20 | 2.98 | 2.99 | 25,148 | 594 | 0% 0% 1% 100% |
Read the ↓ make, command line, and program output logs to see how this program was run.
Read binary-trees benchmark to see what this program should do.
notes
gcc (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
binary-trees C gcc #2 program source code
/* * The Computer Language Benchmarks Game * http://benchmarksgame.alioth.debian.org/ * * Contributed by Mr Ledrug */ #include <stdio.h> #include <stdlib.h> typedef struct node_s { int item; struct node_s *left, *right; } node; node * make_tree(int depth, int root_item) { const int len = 1 << depth; // allocate the whole tree in one go, more of a bin heap really node * const root = (node*)calloc(len, sizeof(node)); root[1].item = root_item; root[1].left = root + 2; root[1].right = root + 3; for (int i = 2; i < len; i++) { root[i].item = 2 * root[i/2].item - 1 + (i&1); if (i * 2 >= len) continue; root[i].left = root + i * 2; root[i].right = root + i * 2 + 1; } return root + 1; } void del_tree(node *s) { free(s - 1); } // It's actually faster to do the check sequentially because the whole // tree is in one array. Here traversing the tree by pointer is just // to show the bin heap functions as a linked tree int check_tree(const node* const s) { if (!s->left) return s->item; return s->item + check_tree(s->left) - check_tree(s->right); } int main(int argc, char **argv) { int min = 4; int max = atoi(argv[1]); if (max < 6) max = 6; node *stretch = make_tree(max + 1, 0); printf("stretch tree of depth %d\t check: %d\n", max + 1, check_tree(stretch)); del_tree(stretch); node *longlived = make_tree(max, 0); for (int d = min; d <= max; d+= 2) { int iter = 1 << (max + min - d); int check = 0; /* this can be easily parallel, unfortunately malloc's locking slows down the thing by a lot with either -pthread or -fopenmp, so much so that it's not worth the hassle */ for (int i = 1; i <= iter; i++){ node *s = make_tree(d, i); check += check_tree(s); del_tree(s); s = make_tree(d, -i); check += check_tree(s); del_tree(s); } printf("%d\t trees of depth %d\t check: %d\n", iter * 2, d, check); } printf("long lived tree of depth %d\t check: %d\n", max, check_tree(longlived)); del_tree(longlived); return 0; }
make, command-line, and program output logs
Sat, 27 Apr 2013 19:00:58 GMT MAKE: /usr/bin/gcc -pipe -Wall -O3 -fomit-frame-pointer -march=native -std=c99 -pthread binarytrees.gcc-2.c -o binarytrees.gcc-2.gcc_run -lm rm binarytrees.gcc-2.c 0.16s to complete and log all make actions COMMAND LINE: ./binarytrees.gcc-2.gcc_run 20 PROGRAM OUTPUT: stretch tree of depth 21 check: -1 2097152 trees of depth 4 check: -2097152 524288 trees of depth 6 check: -524288 131072 trees of depth 8 check: -131072 32768 trees of depth 10 check: -32768 8192 trees of depth 12 check: -8192 2048 trees of depth 14 check: -2048 512 trees of depth 16 check: -512 128 trees of depth 18 check: -128 32 trees of depth 20 check: -32 long lived tree of depth 20 check: -1