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futex_hash_table.c
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futex_hash_table.c
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#include "cacheutils.h"
#include "helper.h"
#include <linux/futex.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <unistd.h>
#include <stdint.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#define TOTAL_FUTEXES 4096
#define LOOP 2
#define FUTEXES 2048
#define REPEAT_MEASUREMENT 512
#define AVERAGE (1<<3)
pthread_t tids[FUTEXES*LOOP];
unsigned int probe_futexes[TOTAL_FUTEXES];
volatile unsigned int futexes[FUTEXES*LOOP*4096];
static int futex(unsigned int *uaddr, int futex_op, unsigned int val, const struct timespec *timeout, unsigned int *uaddr2, unsigned int val3)
{
return syscall(SYS_futex, uaddr, futex_op, val, timeout, uaddr2, val3);
}
void *do_job(void *arg)
{
int ret;
size_t id = (size_t)arg;
id = (id*4096) | (id*8 % 4096);
ret = futex((unsigned int *)&futexes[id], FUTEX_WAIT_PRIVATE, 0, NULL, NULL, 0);
if (ret < 0) {
perror("futex do_job");
exit(-1);
}
return 0;
}
int compare(const void *a, const void *b)
{
return (*(size_t *)a - *(size_t *)b);
}
void print_usage(char *name)
{
printf("%s <struct_agnostic_amp=0> <core=7> <file_name=futex_hash_table_%%s.csv>\n", name);
exit(0);
}
char *name = 0;
size_t software_agnostic_amplification = 0;
size_t core = 7;
int main(int argc, char **argv)
{
static volatile char flush_cache[(1<<10)*(1<<7)];
if (argc > 4)
print_usage(argv[0]);
software_agnostic_amplification = (argc > 1) && strcmp(argv[1], "0");
if (argc > 2)
core = atoi(argv[2]);
if (argc > 3)
name = argv[3];
int ret;
size_t ground_truths[TOTAL_FUTEXES*LOOP] = {0};
size_t times[TOTAL_FUTEXES*LOOP];
pin_to_core(core);
helper_init();
printf("[*] warmup\n");
for (volatile size_t i = 0; i < 0x400000000; ++i);
printf("[*] start\n");
for (size_t j = 0; j < LOOP; ++j) {
printf("[*] %zd/%d\n", j, LOOP);
for (size_t i = 0; i < FUTEXES; ++i) {
size_t id = i+FUTEXES*j;
ret = pthread_create(&tids[id], 0, do_job, (void *)id);
if (ret < 0) {
perror("pthread_create");
exit(-1);
}
}
for (size_t i = 0; i < TOTAL_FUTEXES; ++i) {
size_t t0;
size_t t1;
size_t time = 0;
size_t __times[REPEAT_MEASUREMENT];
for (size_t l = 0; l < REPEAT_MEASUREMENT; ++l) {
sched_yield();
if (software_agnostic_amplification)
memset((char *)flush_cache, 1, sizeof(flush_cache));
t0 = rdtsc_begin();
ret = futex(&probe_futexes[i], FUTEX_WAKE_PRIVATE, 0x10, NULL, NULL, 0);
t1 = rdtsc_end();
__times[l] = t1 - t0;
if (ret < 0) {
perror("futex main");
exit(-1);
}
}
qsort(__times, REPEAT_MEASUREMENT, sizeof(size_t), compare);
for (size_t l = 0; l < AVERAGE; ++l)
time += __times[l];
time /= AVERAGE;
times[i+j*TOTAL_FUTEXES] = time;
futex_read_count((size_t)&ground_truths[i+j*TOTAL_FUTEXES], (size_t)&probe_futexes[i]);
}
sleep(1);
}
for (size_t i = 0; i < TOTAL_FUTEXES*LOOP; ++i) {
if (i % 16 == 0)
printf("[%4zd] ", i);
printf("%4zd (%zd)", times[i], ground_truths[i]);
if (i % 16 == 15)
printf("\n");
}
if (name == 0) {
printf("[?] save to file? [y/N] ");
char in = getchar();
if (in != 'y')
exit(0);
}
time_t current_time;
struct tm *timeinfo;
char buffer[256];
time(¤t_time);
timeinfo = localtime(¤t_time);
strftime(buffer, sizeof(buffer), "%Y%m%d_%H%M%S", timeinfo);
if (name == 0) {
static char file_name[0x1000];
snprintf(file_name, sizeof(file_name), "futex_hash_table_%s.csv", buffer);
name = file_name;
}
FILE *csv_file = fopen(name, "w");
if (csv_file == NULL) {
printf("[!] fopen\n");
return 1;
}
// Write headers
fprintf(csv_file, "ground truth; time\n");
for (size_t i = 0; i < TOTAL_FUTEXES*LOOP; ++i) {
fprintf(csv_file, "%ld; %ld\n", ground_truths[i], times[i]);
}
fclose(csv_file);
printf("[+] done\n");
}