Initial commit: benchmark musl's qsort

7 files changed, 369 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..6271d7c
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,20 @@
+CFLAGS  = -O3 -pipe -std=c99 -D_XOPEN_SOURCE=500
+LDFLAGS =
+
+SRCS    = $(sort $(wildcard *.c))
+OBJS    = $(SRCS:.c=.o)
+BINS    = bench
+
+.PHONY: all clean
+
+all: $(BINS)
+
+clean:
+	rm -f $(BINS)
+	rm -f $(OBJS)
+
+bench: $(OBJS)
+	$(CC) $(LDFLAGS) $^ -o $@
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
diff --git a/bench.c b/bench.c
new file mode 100644
index 0000000..fb46b94
--- /dev/null
+++ b/bench.c
@@ -0,0 +1,72 @@
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include "generators.h"
+#include "sorters.h"
+
+#define MIN_SIZE 10000
+#define MAX_SIZE 10000000
+
+static int buffer[MAX_SIZE];
+static unsigned long comparisons;
+
+static int compare(const void *a, const void *b)
+{
+	const int *aa = a;
+	const int *bb = b;
+
+	comparisons++;
+	if (*aa < *bb)
+		return -1;
+	else if (*aa > *bb)
+		return 1;
+	else
+		return 0;
+}
+
+#define CMP_WIDTH  12
+#define MS_WIDTH   6
+#define SORT_WIDTH 10
+#define GEN_WIDTH  (CMP_WIDTH + MS_WIDTH + 1)
+#define SIZE_WIDTH 10
+
+static inline unsigned long timediff_ms(struct timespec *start, struct timespec *stop)
+{
+	return 1000 * (stop->tv_sec - start->tv_sec) + (stop->tv_nsec - start->tv_nsec) / 1000000;
+}
+
+int main()
+{
+	struct timespec start, stop;
+
+	printf("%-*s ", SORT_WIDTH, "");
+	for (const struct generator *g = generators; g->name; g++)
+		printf("%*s ", GEN_WIDTH, g->name);
+	printf(" %*s\n%-*s ", SIZE_WIDTH, "elements", SORT_WIDTH, "");
+	for (const struct generator *g = generators; g->name; g++)
+		printf("%*s %*s ", CMP_WIDTH, "compares", MS_WIDTH, "ms");
+	puts("");
+
+	for (const struct sorter *s = sorters; s->name; s++) {
+		for (size_t size = MAX_SIZE; size >= MIN_SIZE; size /= 10) {
+			printf("%-*s ", SORT_WIDTH, size == MAX_SIZE ? s->name : "");
+			for (const struct generator *g = generators; g->name; g++) {
+				comparisons = 0;
+				g->func(buffer, size);
+
+				if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &start)) abort();
+				s->func(buffer, size, sizeof(int), compare);
+				if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &stop)) abort();
+
+				printf("%*lu %*lu ", CMP_WIDTH, comparisons, MS_WIDTH, timediff_ms(&start, &stop));
+			}
+			printf(" %*zu\n", SIZE_WIDTH, size);
+		}
+		puts("");
+	}
+
+	return 0;
+}
+
diff --git a/generators.c b/generators.c
new file mode 100644
index 0000000..002b128
--- /dev/null
+++ b/generators.c
@@ -0,0 +1,34 @@
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+#include "generators.h"
+
+static void generate_random(int *buffer, size_t size)
+{
+	srandom(1);
+	for (size_t i = 0; i < size; i++) buffer[i] = random();
+}
+
+static void generate_sorted(int *buffer, size_t size)
+{
+	for (size_t i = 0; i < size; i++) buffer[i] = i;
+}
+
+static void generate_reverse(int *buffer, size_t size)
+{
+	for (size_t i = 0; i < size; i++) buffer[i] = INT_MAX - i;
+}
+
+static void generate_constant(int *buffer, size_t size)
+{
+	for (size_t i = 0; i < size; i++) buffer[i] = 42;
+}
+
+const struct generator generators[] = {
+	{ .name = "random",   .func = generate_random   },
+	{ .name = "sorted",   .func = generate_sorted   },
+	{ .name = "reverse",  .func = generate_reverse  },
+	{ .name = "constant", .func = generate_constant },
+	{ 0 }
+};
diff --git a/generators.h b/generators.h
new file mode 100644
index 0000000..e08a0be
--- /dev/null
+++ b/generators.h
@@ -0,0 +1,8 @@
+#include <stddef.h>
+
+typedef void (*generatorfn)(int *, size_t);
+
+extern const struct generator {
+	const char *name;
+	generatorfn func;
+} generators[];
diff --git a/musl_qsort.c b/musl_qsort.c
new file mode 100644
index 0000000..21a39bd
--- /dev/null
+++ b/musl_qsort.c
@@ -0,0 +1,218 @@
+/* Copyright (C) 2011 by Valentin Ochs
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/* Minor changes by Rich Felker for integration in musl, 2011-04-27. */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sorters.h"
+
+static inline int ntz(uint64_t x)
+{
+	__asm__( "bsf %1,%0" : "=r"(x) : "r"(x) );
+	return x;
+}
+
+static inline int pntz(size_t p[2]) {
+	int r = ntz(p[0] - 1);
+	if(r != 0 || (r = 8*sizeof(size_t) + ntz(p[1])) != 8*sizeof(size_t)) {
+		return r;
+	}
+	return 0;
+}
+
+static void cycle(size_t width, unsigned char* ar[], int n)
+{
+	unsigned char tmp[256];
+	size_t l;
+	int i;
+
+	if(n < 2) {
+		return;
+	}
+
+	ar[n] = tmp;
+	while(width) {
+		l = sizeof(tmp) < width ? sizeof(tmp) : width;
+		memcpy(ar[n], ar[0], l);
+		for(i = 0; i < n; i++) {
+			memcpy(ar[i], ar[i + 1], l);
+			ar[i] += l;
+		}
+		width -= l;
+	}
+}
+
+/* shl() and shr() need n > 0 */
+static inline void shl(size_t p[2], int n)
+{
+	if(n >= 8 * sizeof(size_t)) {
+		n -= 8 * sizeof(size_t);
+		p[1] = p[0];
+		p[0] = 0;
+	}
+	p[1] <<= n;
+	p[1] |= p[0] >> (sizeof(size_t) * 8 - n);
+	p[0] <<= n;
+}
+
+static inline void shr(size_t p[2], int n)
+{
+	if(n >= 8 * sizeof(size_t)) {
+		n -= 8 * sizeof(size_t);
+		p[0] = p[1];
+		p[1] = 0;
+	}
+	p[0] >>= n;
+	p[0] |= p[1] << (sizeof(size_t) * 8 - n);
+	p[1] >>= n;
+}
+
+static void sift(unsigned char *head, size_t width, cmpfun cmp, int pshift, size_t lp[])
+{
+	unsigned char *rt, *lf;
+	unsigned char *ar[14 * sizeof(size_t) + 1];
+	int i = 1;
+
+	ar[0] = head;
+	while(pshift > 1) {
+		rt = head - width;
+		lf = head - width - lp[pshift - 2];
+
+		if((*cmp)(ar[0], lf) >= 0 && (*cmp)(ar[0], rt) >= 0) {
+			break;
+		}
+		if((*cmp)(lf, rt) >= 0) {
+			ar[i++] = lf;
+			head = lf;
+			pshift -= 1;
+		} else {
+			ar[i++] = rt;
+			head = rt;
+			pshift -= 2;
+		}
+	}
+	cycle(width, ar, i);
+}
+
+static void trinkle(unsigned char *head, size_t width, cmpfun cmp, size_t pp[2], int pshift, int trusty, size_t lp[])
+{
+	unsigned char *stepson,
+	              *rt, *lf;
+	size_t p[2];
+	unsigned char *ar[14 * sizeof(size_t) + 1];
+	int i = 1;
+	int trail;
+
+	p[0] = pp[0];
+	p[1] = pp[1];
+
+	ar[0] = head;
+	while(p[0] != 1 || p[1] != 0) {
+		stepson = head - lp[pshift];
+		if((*cmp)(stepson, ar[0]) <= 0) {
+			break;
+		}
+		if(!trusty && pshift > 1) {
+			rt = head - width;
+			lf = head - width - lp[pshift - 2];
+			if((*cmp)(rt, stepson) >= 0 || (*cmp)(lf, stepson) >= 0) {
+				break;
+			}
+		}
+
+		ar[i++] = stepson;
+		head = stepson;
+		trail = pntz(p);
+		shr(p, trail);
+		pshift += trail;
+		trusty = 0;
+	}
+	if(!trusty) {
+		cycle(width, ar, i);
+		sift(head, width, cmp, pshift, lp);
+	}
+}
+
+void qsort_musl(void *base, size_t nel, size_t width, cmpfun cmp)
+{
+	size_t lp[12*sizeof(size_t)];
+	size_t i, size = width * nel;
+	unsigned char *head, *high;
+	size_t p[2] = {1, 0};
+	int pshift = 1;
+	int trail;
+
+	if (!size) return;
+
+	head = base;
+	high = head + size - width;
+
+	/* Precompute Leonardo numbers, scaled by element width */
+	for(lp[0]=lp[1]=width, i=2; (lp[i]=lp[i-2]+lp[i-1]+width) < size; i++);
+
+	while(head < high) {
+		if((p[0] & 3) == 3) {
+			sift(head, width, cmp, pshift, lp);
+			shr(p, 2);
+			pshift += 2;
+		} else {
+			if(lp[pshift - 1] >= high - head) {
+				trinkle(head, width, cmp, p, pshift, 0, lp);
+			} else {
+				sift(head, width, cmp, pshift, lp);
+			}
+
+			if(pshift == 1) {
+				shl(p, 1);
+				pshift = 0;
+			} else {
+				shl(p, pshift - 1);
+				pshift = 1;
+			}
+		}
+
+		p[0] |= 1;
+		head += width;
+	}
+
+	trinkle(head, width, cmp, p, pshift, 0, lp);
+
+	while(pshift != 1 || p[0] != 1 || p[1] != 0) {
+		if(pshift <= 1) {
+			trail = pntz(p);
+			shr(p, trail);
+			pshift += trail;
+		} else {
+			shl(p, 2);
+			pshift -= 2;
+			p[0] ^= 7;
+			shr(p, 1);
+			trinkle(head - lp[pshift] - width, width, cmp, p, pshift + 1, 1, lp);
+			shl(p, 1);
+			p[0] |= 1;
+			trinkle(head - width, width, cmp, p, pshift, 1, lp);
+		}
+		head -= width;
+	}
+}
diff --git a/sorters.c b/sorters.c
new file mode 100644
index 0000000..a630136
--- /dev/null
+++ b/sorters.c
@@ -0,0 +1,6 @@
+#include "sorters.h"
+
+const struct sorter sorters[] = {
+	{ .name = "musl", .func = qsort_musl },
+	{ 0 }
+};
diff --git a/sorters.h b/sorters.h
new file mode 100644
index 0000000..1a2397a
--- /dev/null
+++ b/sorters.h
@@ -0,0 +1,11 @@
+#include <stddef.h>
+
+typedef int  (*cmpfun)(const void *, const void *);
+typedef void (*sorter)(void *, size_t, size_t, cmpfun);
+
+void qsort_musl(void *, size_t, size_t, cmpfun);
+
+extern const struct sorter {
+	const char *name;
+	sorter func;
+} sorters[];