samples/compare/host.c

/*
 * Copyright 2008 Sony Corporation of America
 *
 *
 * 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.
 */

#include <sys/time.h>
#include <string.h>
#include <pthread.h>
#include <libspe2.h>
#include <mars/task.h>

#define INFO	\
"\
Comparison: libmars v.s. libspe2				\n\
--------------------------------				\n\
This program compares the performance of running multiple	\n\
task contexts between libspe and libmars. This aims to show	\n\
the high cost of libspe's context switching.			\n\
								\n\
When a program needs to execute N number of MPU tasks		\n\
using libspe, N spe contexts must be created and executed.	\n\
During execution, the kernel's spufs scheduler will context	\n\
switch in and out these N spe contexts which entail very high	\n\
costs.								\n\
								\n\
The MARS library avoids the expensive spe context switches	\n\
by having the MARS kernel handle its own MARS task context	\n\
management, and keeping the MARS kernel resident on the MPUs.	\n\
								\n\
As the following results will show, as the number of tasks	\n\
increase, the slightly larger overhead of the MARS library is	\n\
quickly minisculed by the linearly increasing cost of libspe's	\n\
spe context switching. The resuling ERROR in libspe's results	\n\
is due to the fact that libspe has reached the limit of how	\n\
many spe contexts can be created at once.			\n\
								\n\
tasks: number of task contexts created				\n\
loop:  number of iterations processed in each task context	\n\
\n"

#define TIMER_START(timer)\
{\
	struct timeval tv;\
	gettimeofday(&tv, NULL);\
	timer = tv.tv_sec * 1000000 + tv.tv_usec;\
}

#define TIMER_STOP(timer)\
{\
	struct timeval tv;\
	gettimeofday(&tv, NULL);\
	timer = tv.tv_sec * 1000000 + tv.tv_usec - timer;\
}

extern struct spe_program_handle mpu_task_libmars_prog;
extern struct spe_program_handle mpu_task_libspe2_prog;

typedef struct {
	char name[32];
	int loop;
} pthread_arg;

static void *spe_context_thread(void *arg)
{
	struct mars_task_id task_id __attribute__((aligned(16)));
	struct mars_task_args task_args __attribute__((aligned(16)));
	task_args.type.u32[0] = ((pthread_arg *)arg)->loop;
	strcpy((char *)&task_id.name, ((pthread_arg *)arg)->name);

	unsigned int entry = SPE_DEFAULT_ENTRY;
	struct spe_context *spe;

	spe = spe_context_create(0, NULL);
	spe_program_load(spe, &mpu_task_libspe2_prog);
	spe_context_run(spe, &entry, 0, &task_id, &task_args, NULL);
	spe_context_destroy(spe);

	pthread_exit(0);

	return NULL;
}

static int libspe2(int task, int loop)
{
	int i;
	int ret = 0;
	int initialized = 0;

	pthread_t spe_context_threads[task];
	pthread_arg spe_context_thread_arg[task];

	for (i = 0; i < task; i++) {
		sprintf(spe_context_thread_arg[i].name, "libspe2 Task %d", i);
		spe_context_thread_arg[i].loop = loop;
		ret = pthread_create(&spe_context_threads[i], NULL,
				(void *)spe_context_thread,
				(void *)&spe_context_thread_arg[i]);
		if (ret) {
			initialized = i;
			break;
		}
	}

	if (ret) {
		for (i = 0; i < initialized; i++) {
			pthread_join(spe_context_threads[i], NULL);
		}
		return -1;
	}

	for (i = 0; i < task; i++) {
		ret = pthread_join(spe_context_threads[i], NULL);
		if (ret)
			return -1;
	}

	return 0;
}

static int libmars(int task, int loop)
{
	int i;
	int ret;
	char name[task][32];

	struct mars_context *mars_ctx;
	struct mars_task_id task_id[task];
	struct mars_task_args task_args;

	ret = mars_context_create(&mars_ctx, 0, 0);
	if (ret)
		return -1;

	for (i = 0; i < task; i++) {
		sprintf((char *)&name[i], "libmars Task %d", i);
		ret = mars_task_create(mars_ctx, &task_id[i], name[i],
			mpu_task_libmars_prog.elf_image, 0);
		if (ret)
			return -1;

		task_args.type.u32[0] = loop;
		ret = mars_task_schedule(&task_id[i], &task_args, 0);
		if (ret)
			return -1;
	}

	for (i = 0; i < task; i++) {
		ret = mars_task_wait(&task_id[i], NULL);
		if (ret)
			return -1;

		ret = mars_task_destroy(&task_id[i]);
		if (ret)
			return -1;
	}

	ret = mars_context_destroy(mars_ctx);
	if (ret)
		return -1;

	return 0;
}

static void compare(int task, int loop)
{
	int ret_libspe2;
	unsigned long long timer_libspe2;
	TIMER_START(timer_libspe2);
	ret_libspe2 = libspe2(task, loop);
	TIMER_STOP(timer_libspe2);

	int ret_libmars;
	unsigned long long timer_libmars;
	TIMER_START(timer_libmars);
	ret_libmars = libmars(task, loop);
	TIMER_STOP(timer_libmars);

        printf("| %9d | %9d |", task, loop);

	if (ret_libspe2)
		printf("    ERROR    ");
	else
		printf(" %8.0f us ", (float)timer_libspe2);

	printf("|");

	if (ret_libmars)
		printf("    ERROR    ");
	else
		printf(" %8.0f us ", (float)timer_libmars);

	printf("|\n");
}

int main(void)
{
	int task, loop;

	printf(INFO);

	printf("-----------------------------------------------------\n");
	printf("|   tasks   |   loop    |   libspe2   |   libmars   |\n");
	printf("-----------------------------------------------------\n");

	for (task = 1; task <= 100; task *= 10) {
		for (loop = 1; loop <= 1000000; loop *= 10) {
			compare(task, loop);
		}
	}

	for (task = 200; task <= 400; task *= 2) {
		for (loop = 1; loop <= 1000000; loop *= 10) {
			compare(task, loop);
		}
	}

	printf("-----------------------------------------------------\n");

	return 0;
}