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Date: Tue, 31 Jul 2018 08:22:05 +0000
From: Eric Wong <normalperson@yhbt.net>
To: spew@80x24.org
Subject: xthr.c
Message-ID: <20180731082205.vykyunsm5xg7ml3e@dcvr>
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/*
 * Cross-thread memory allocation test
 * Copyright (C) 2014-2018, Eric Wong <e@80x24.org>
 * License: LGPLv2.1 or later (depends on URCU)
 *
 * gcc -o xthr xthr.c -O3 -pthread -lurcu-cds -lurcu
 * Usage: xthr [-a NALLOC] [-m BYTES] [-i ITERATIONS]
 *
 * -a number of threads doing allocation (default:1)
 * -m malloc size in bytes (default:1 word (4-8 bytes))
 * -i total number of malloc/free pairs (default:1024)
 */
#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <urcu.h>
#include <urcu/wfcqueue.h>
#include <urcu/compiler.h>
#include <sys/types.h>
#include <err.h>
#include <stdio.h>

static int memzero;
static size_t iter = 1024;
static size_t alloc_bytes = sizeof(struct rcu_head);

static void do_free(struct rcu_head *head)
{
	free(head);
}

static void *do_alloc(void *arg)
{
	const size_t max = (const size_t)arg;
	const size_t bytes = alloc_bytes;
	size_t i;

	rcu_register_thread();

	if (memzero) {
		const size_t zbytes = bytes - CAA_CACHE_LINE_SIZE;
		for (i = 0; i < max; i++) {
			struct rcu_head *node = malloc(bytes);
			if (!node) errx(1, "malloc failed");

			memset(node, 0, zbytes);
			call_rcu(node, do_free);
		}
	} else {
		for (i = 0; i < max; i++) {
			struct rcu_head *node = malloc(bytes);
			if (!node) errx(1, "malloc failed");

			call_rcu(node, do_free);
		}
	}
	rcu_unregister_thread();
	return NULL;
}

int main(int argc, char *argv[])
{
	size_t i;
	unsigned long nalloc = 1, nfree = 1;
	pthread_t *th_alloc;
	int err;
	int opt;
	unsigned long call_rcu_flags = 0;

	rcu_init();
	rcu_register_thread();

	while ((opt = getopt(argc, argv, "a:m:i:zr")) != -1) {
		char *end;
		size_t c = 0;
		switch (opt) {
		case 'a': c = nalloc = strtoul(optarg, &end, 10); break;
		case 'm': c = alloc_bytes = strtoul(optarg, &end, 10); break;
		case 'i': c = iter = strtoul(optarg, &end, 10); break;
		case 'r': call_rcu_flags = URCU_CALL_RCU_RT; continue;
		case 'z': memzero = 1; continue;
		default: errx(1, "bad arg: -%c", opt);
		}
		if (*end) errx(1, "trailing bytes: %s", end);
		if (c == 0) errx(1, "-%c must be non-zero", opt);
	}

	if (alloc_bytes < sizeof(struct rcu_head)) {
		alloc_bytes = sizeof(struct rcu_head);
		fprintf(stderr, "-m clamped to %zu bytes\n", alloc_bytes);
	}
	if (memzero && alloc_bytes <= CAA_CACHE_LINE_SIZE)
		memzero = 0;

	th_alloc = malloc(sizeof(pthread_t) * nalloc);
	if (!th_alloc)
		errx(1, "malloc fails");

	for (i = 0; i < nalloc; i++) {
		size_t n = iter / nalloc;
		if (i == 0) n += iter % nalloc;

		err = pthread_create(&th_alloc[i], NULL, do_alloc, (void *)n);
		if (err != 0)
			errx(1, "failed to create thread: %s", strerror(err));
	}

	for (i = 0; i < nalloc; i++) {
		err = pthread_join(th_alloc[i], NULL);
		if (err != 0)
			errx(1, "failed to join thread: %s", strerror(err));
	}

	rcu_barrier();
	rcu_unregister_thread();

	return 0;
}