From d58dc6c95d9044ffafa08b4327f5abbf0f5b54e0 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fl.fischer@fau.de>
Date: Wed, 8 Apr 2020 16:20:29 +0200
Subject: add micro benchmark measureing malloc using rdtsc

---
 src/benchmarks/rdtsc/rdtsc.c | 104 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 src/benchmarks/rdtsc/rdtsc.c

(limited to 'src/benchmarks/rdtsc/rdtsc.c')

diff --git a/src/benchmarks/rdtsc/rdtsc.c b/src/benchmarks/rdtsc/rdtsc.c
new file mode 100644
index 0000000..33a8626
--- /dev/null
+++ b/src/benchmarks/rdtsc/rdtsc.c
@@ -0,0 +1,104 @@
+#define _GNU_SOURCE             /* See feature_test_macros(7) */
+#include <pthread.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/sysinfo.h>
+
+int mode = 0;
+int size = 64;
+int iterations = 100000;
+int num_cpus;
+
+static __inline__ int64_t rdtsc_s(void)
+{
+	unsigned a, d;
+	asm volatile("cpuid" ::: "%rax", "%rbx", "%rcx", "%rdx");
+	asm volatile("rdtsc" : "=a" (a), "=d" (d));
+	return ((unsigned long)a) | (((unsigned long)d) << 32);
+}
+
+static __inline__ int64_t rdtsc_e(void)
+{
+	unsigned a, d;
+	asm volatile("rdtscp" : "=a" (a), "=d" (d));
+	asm volatile("cpuid" ::: "%rax", "%rbx", "%rcx", "%rdx");
+	return ((unsigned long)a) | (((unsigned long)d) << 32);
+}
+
+static void* test_thread_func(void* arg) {
+	int64_t clock_before, clock_after;
+	void* p;
+
+	int64_t* clocks = malloc(iterations * sizeof(int64_t));
+	if (!clocks)
+		abort();
+
+	// set cpu affinity to prevent cpu switching
+	int64_t tid = (int64_t) arg;
+	cpu_set_t my_cpu;
+	/* Skip CPU0 - let the OS run on that one */
+	int my_cpu_num = (tid % (num_cpus-1))+1;
+
+	CPU_ZERO (&my_cpu);
+	/* CPU_SET (my_cpu_num, &my_cpu); */
+	CPU_SET (3, &my_cpu);
+	if (sched_setaffinity (0, sizeof(my_cpu), &my_cpu) == -1)
+	  perror ("setaffinity failed");
+
+	for(int i = 0; i < iterations; i++) {
+		clock_before = rdtsc_s();
+		p = malloc(size);
+		clock_after = rdtsc_e();
+
+		// measure potentially cached allocations
+		if (mode)
+			free(p);
+
+		clocks[i] = clock_after - clock_before;
+	}
+
+	for(int i = 0; i < iterations; i++) {
+		printf("malloc(%d): %d cycles\n", size, clocks[i]);
+	}
+
+	return NULL;
+}
+
+int main(int argc, char* argv[]) {
+	pthread_t* threads;
+	int num_threads = 1;
+
+	num_cpus = get_nprocs();
+
+	if (argc > 5) {
+		fprintf(stderr, "Usage: %s <iterations> <size> <num threads>\n", argv[0]);
+		return 1;
+	}
+
+	if (argc > 1 && strncmp(argv[1], "cached", strlen("cached"))) mode = 1;
+	if (argc > 2) iterations = atoi(argv[2]);
+	if (argc > 3) size = atoi(argv[3]);
+	if (argc > 4) num_threads = atoi(argv[4]);
+
+	fprintf(stderr, "iterations = %d; size = %d; threads = %d\n", iterations, size, num_threads);
+
+	threads = (pthread_t*) malloc(num_threads * sizeof(pthread_t));
+
+	for (int i = 0; i < num_threads; i++) {
+		if (0 != pthread_create(&threads[i], NULL, test_thread_func, NULL)) {
+			perror("pthread_create");
+			return 1;
+		}
+	}
+
+	for(int i = 0; i < num_threads; i++) {
+		if (0 != pthread_join(threads[i], NULL)) {
+			perror("pthread_join");
+			return 1;
+		}
+	}
+
+	return 0;
+}
-- 
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