Message-ID: <9078c923-237f-db46-73a2-97ffd8e229ac@huawei.com>
Date:   Fri, 25 Jun 2021 15:40:47 +0800
From:   Yunsheng Lin <linyunsheng@...wei.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
CC:     <davem@...emloft.net>, <kuba@...nel.org>, <jasowang@...hat.com>,
        <brouer@...hat.com>, <paulmck@...nel.org>, <peterz@...radead.org>,
        <will@...nel.org>, <shuah@...nel.org>,
        <linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>,
        <linux-kselftest@...r.kernel.org>, <linuxarm@...neuler.org>
Subject: Re: [PATCH net-next v2 1/2] selftests/ptr_ring: add benchmark
 application for ptr_ring

On 2021/6/25 14:37, Michael S. Tsirkin wrote:
> On Fri, Jun 25, 2021 at 11:18:55AM +0800, Yunsheng Lin wrote:
>> Currently ptr_ring selftest is embedded within the virtio
>> selftest, which involves some specific virtio operation,
>> such as notifying and kicking.
>>
>> As ptr_ring has been used by various subsystems, it deserves
>> it's owner's selftest in order to benchmark different usecase
>> of ptr_ring, such as page pool and pfifo_fast qdisc.
>>
>> So add a simple application to benchmark ptr_ring performance.
>> Currently two test mode is supported:
>> Mode 0: Both enqueuing and dequeuing is done in a single thread,
>>         it is called simple test mode in the test app.
>> Mode 1: Enqueuing and dequeuing is done in different thread
>>         concurrently, also known as SPSC(single-producer/
>>         single-consumer) test.
>>
>> The multi-producer/single-consumer test for pfifo_fast case is
>> not added yet, which can be added if using CAS atomic operation
>> to enable lockless multi-producer is proved to be better than
>> using r->producer_lock.
>>
>> Only supported on x86 and arm64 for now.
>>
>> Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
>> ---
>>  MAINTAINERS                                      |   5 +
>>  tools/testing/selftests/ptr_ring/Makefile        |   6 +
>>  tools/testing/selftests/ptr_ring/ptr_ring_test.c | 249 +++++++++++++++++++++++
>>  tools/testing/selftests/ptr_ring/ptr_ring_test.h | 150 ++++++++++++++
>>  4 files changed, 410 insertions(+)
>>  create mode 100644 tools/testing/selftests/ptr_ring/Makefile
>>  create mode 100644 tools/testing/selftests/ptr_ring/ptr_ring_test.c
>>  create mode 100644 tools/testing/selftests/ptr_ring/ptr_ring_test.h
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index cc375fd..1227022 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -14847,6 +14847,11 @@ F:	drivers/net/phy/dp83640*
>>  F:	drivers/ptp/*
>>  F:	include/linux/ptp_cl*
>>  
>> +PTR RING BENCHMARK
>> +M:	Yunsheng Lin <linyunsheng@...wei.com>
>> +L:	netdev@...r.kernel.org
>> +F:	tools/testing/selftests/ptr_ring/
>> +
>>  PTRACE SUPPORT
>>  M:	Oleg Nesterov <oleg@...hat.com>
>>  S:	Maintained
>> diff --git a/tools/testing/selftests/ptr_ring/Makefile b/tools/testing/selftests/ptr_ring/Makefile
>> new file mode 100644
>> index 0000000..346dea9
>> --- /dev/null
>> +++ b/tools/testing/selftests/ptr_ring/Makefile
>> @@ -0,0 +1,6 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +LDLIBS = -lpthread
>> +
>> +TEST_GEN_PROGS := ptr_ring_test
>> +
>> +include ../lib.mk
>> diff --git a/tools/testing/selftests/ptr_ring/ptr_ring_test.c b/tools/testing/selftests/ptr_ring/ptr_ring_test.c
>> new file mode 100644
>> index 0000000..4f32d3d
>> --- /dev/null
>> +++ b/tools/testing/selftests/ptr_ring/ptr_ring_test.c
>> @@ -0,0 +1,249 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
> 
> Can we keep this GPL-2.0-or-later same as ptr ring itself?
> Encourages reuse ...

Ok.

> 
>> +/*
>> + * Copyright (C) 2021 HiSilicon Limited.
>> + */
>> +
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <unistd.h>
>> +#include <string.h>
>> +#include <errno.h>
>> +#include <sys/time.h>
>> +#include <malloc.h>
>> +#include <assert.h>
>> +#include <stdbool.h>
>> +#include <pthread.h>
>> +
>> +#include "ptr_ring_test.h"
>> +#include "../../../../include/linux/ptr_ring.h"
>> +
>> +#define MIN_RING_SIZE	2
>> +#define MAX_RING_SIZE	10000000
>> +
>> +static struct ptr_ring ring ____cacheline_aligned_in_smp;
>> +
>> +struct worker_info {
>> +	pthread_t tid;
>> +	int test_count;
>> +	bool error;
>> +	long duration_us;
>> +};
>> +
>> +static void *produce_worker(void *arg)
>> +{
>> +	struct worker_info *info = arg;
>> +	struct timeval start, end;
>> +	unsigned long i = 0;
>> +	long sec, us;
>> +	int ret;
>> +
>> +	gettimeofday(&start, NULL);
>> +
>> +	while (++i <= info->test_count) {
>> +		while (__ptr_ring_full(&ring))
>> +			cpu_relax();
>> +
>> +		ret = __ptr_ring_produce(&ring, (void *)i);
>> +		if (ret) {
>> +			fprintf(stderr, "produce failed: %d\n", ret);
>> +			info->error = true;
>> +			return NULL;
>> +		}
>> +	}
>> +
>> +	gettimeofday(&end, NULL);
>> +
>> +	sec = (end.tv_sec - start.tv_sec);
>> +	us = ((sec * 1000000) + end.tv_usec) - (start.tv_usec);
>> +	info->duration_us = us;
>> +	info->error = false;
>> +
>> +	return NULL;
>> +}
> 
> perf does all of this and more. Let's not reinvent the wheel - just run
> the test.

You are suggesting to use perf stat + "test cmd" and remove
the above timestamp sampling, right?

> 
>> +
>> +static void *consume_worker(void *arg)
>> +{
>> +	struct worker_info *info = arg;
>> +	struct timeval start, end;
>> +	unsigned long i = 0;
>> +	long sec, us;
>> +	int *ptr;
>> +
>> +	gettimeofday(&start, NULL);
>> +
>> +	while (++i <= info->test_count) {
>> +		while (__ptr_ring_empty(&ring))
>> +			cpu_relax();
>> +
>> +		ptr = __ptr_ring_consume(&ring);
>> +		if ((unsigned long)ptr != i) {
>> +			fprintf(stderr, "consumer failed, ptr: %lu, i: %lu\n",
>> +				(unsigned long)ptr, i);
>> +			info->error = true;
>> +			return NULL;
>> +		}
>> +	}
>> +
>> +	gettimeofday(&end, NULL);
>> +
>> +	if (!__ptr_ring_empty(&ring)) {
>> +		fprintf(stderr, "ring should be empty, test failed\n");
>> +		info->error = true;
>> +		return NULL;
>> +	}
>> +
>> +	sec = (end.tv_sec - start.tv_sec);
>> +	us = ((sec * 1000000) + end.tv_usec) - (start.tv_usec);
>> +	info->duration_us = us;
>> +	info->error = false;
>> +	return NULL;
>> +}
>> +
>> +/* test case for single producer single consumer */
>> +static void spsc_test(int size, int count)
>> +{
>> +	struct worker_info producer, consumer;
>> +	pthread_attr_t attr;
>> +	void *res;
>> +	int ret;
>> +
>> +	ret = ptr_ring_init(&ring, size, 0);
>> +	if (ret) {
>> +		fprintf(stderr, "init failed: %d\n", ret);
>> +		return;
>> +	}
>> +
>> +	producer.test_count = count;
>> +	consumer.test_count = count;
>> +
>> +	ret = pthread_attr_init(&attr);
>> +	if (ret) {
>> +		fprintf(stderr, "pthread attr init failed: %d\n", ret);
>> +		goto out;
>> +	}
>> +
>> +	ret = pthread_create(&producer.tid, &attr,
>> +			     produce_worker, &producer);
>> +	if (ret) {
>> +		fprintf(stderr, "create producer thread failed: %d\n", ret);
>> +		goto out;
>> +	}
>> +
>> +	ret = pthread_create(&consumer.tid, &attr,
>> +			     consume_worker, &consumer);
>> +	if (ret) {
>> +		fprintf(stderr, "create consumer thread failed: %d\n", ret);
>> +		goto out;
>> +	}
>> +
>> +	ret = pthread_join(producer.tid, &res);
>> +	if (ret) {
>> +		fprintf(stderr, "join producer thread failed: %d\n", ret);
>> +		goto out;
>> +	}
>> +
>> +	ret = pthread_join(consumer.tid, &res);
>> +	if (ret) {
>> +		fprintf(stderr, "join consumer thread failed: %d\n", ret);
>> +		goto out;
>> +	}
>> +
>> +	if (producer.error || consumer.error) {
>> +		fprintf(stderr, "spsc test failed\n");
>> +		goto out;
>> +	}
>> +
>> +	printf("ptr_ring(size:%d) perf spsc test for %d times, took %ld us + %ld us\n",
>> +	       size, count, producer.duration_us, consumer.duration_us);
>> +out:
>> +	ptr_ring_cleanup(&ring, NULL);
>> +}
>> +
>> +static void simple_test(int size, int count)
>> +{
>> +	struct timeval start, end;
>> +	long sec, us;
>> +	int i = 0;
>> +	int *ptr;
>> +	int ret;
>> +
>> +	ret = ptr_ring_init(&ring, size, 0);
>> +	if (ret) {
>> +		fprintf(stderr, "init failed: %d\n", ret);
>> +		return;
>> +	}
>> +
>> +	gettimeofday(&start, NULL);
>> +
>> +	while (++i <= count) {
>> +		ret = __ptr_ring_produce(&ring, &count);
>> +		if (ret) {
>> +			fprintf(stderr, "produce failed: %d\n", ret);
>> +			goto out;
>> +		}
>> +
>> +		ptr = __ptr_ring_consume(&ring);
>> +		if (ptr != &count)  {
>> +			fprintf(stderr, "consume failed: %p\n", ptr);
>> +			goto out;
>> +		}
>> +	}
>> +
>> +	gettimeofday(&end, NULL);
>> +	sec = (end.tv_sec - start.tv_sec);
>> +	us = ((sec * 1000000) + end.tv_usec) - (start.tv_usec);
>> +	printf("ptr_ring(size:%d) perf simple test for %d times, took %ld us\n",
>> +	       size, count, us);
>> +
>> +out:
>> +	ptr_ring_cleanup(&ring, NULL);
>> +}
>> +
>> +int main(int argc, char *argv[])
>> +{
>> +	int count = 1000000;
>> +	int size = 1000;
>> +	int mode = 0;
>> +	int opt;
>> +
>> +	while ((opt = getopt(argc, argv, "N:s:m:")) != -1) {
>> +		switch (opt) {
>> +		case 'N':
>> +			count = atoi(optarg);
>> +			break;
>> +		case 's':
>> +			size = atoi(optarg);
>> +			break;
>> +		case 'm':
>> +			mode = atoi(optarg);
>> +			break;
>> +		default:
>> +			return -1;
>> +		}
>> +	}
>> +
>> +	if (count <= 0) {
>> +		fprintf(stderr, "invalid test count, must be > 0\n");
>> +		return -1;
>> +	}
>> +
>> +	if (size < MIN_RING_SIZE || size > MAX_RING_SIZE) {
>> +		fprintf(stderr, "invalid ring size, must be in %d-%d\n",
>> +			MIN_RING_SIZE, MAX_RING_SIZE);
>> +		return -1;
>> +	}
>> +
>> +	switch (mode) {
>> +	case 0:
>> +		simple_test(size, count);
>> +		break;
>> +	case 1:
>> +		spsc_test(size, count);
>> +		break;
>> +	default:
>> +		fprintf(stderr, "invalid test mode\n");
>> +		return -1;
>> +	}
>> +
>> +	return 0;
>> +}
>> diff --git a/tools/testing/selftests/ptr_ring/ptr_ring_test.h b/tools/testing/selftests/ptr_ring/ptr_ring_test.h
>> new file mode 100644
>> index 0000000..6bf2494
>> --- /dev/null
>> +++ b/tools/testing/selftests/ptr_ring/ptr_ring_test.h
>> @@ -0,0 +1,150 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> 
> We already have hacks like this in the virtio test.
> Let's refactor not duplicate please.

Yes, I took most of below from virtio test.
But I am not sure I understand what you meant by refactoring.
Are you suggesting to use function from standard C library
instead of using the below "#if defined" hack?

I am not sure if all of the below function has a similiar
one in standard C library.

Would you be more specific about what does refactoring
mean?

> 
> 
>> +
>> +#ifndef _TEST_PTR_RING_IMPL_H
>> +#define _TEST_PTR_RING_IMPL_H
>> +
>> +#if defined(__x86_64__) || defined(__i386__)
>> +static inline void cpu_relax(void)
>> +{
>> +	asm volatile ("rep; nop" ::: "memory");
>> +}
>> +#elif defined(__aarch64__)
>> +static inline void cpu_relax(void)
>> +{
>> +	asm volatile("yield" ::: "memory");
>> +}
>> +#else
>> +#define cpu_relax() assert(0)
>> +#endif
>> +
>> +static inline void barrier(void)
>> +{
>> +	asm volatile("" ::: "memory");
>> +}
>> +
>> +/*
>> + * This abuses the atomic builtins for thread fences, and
>> + * adds a compiler barrier.
>> + */
>> +#define smp_release() do { \
>> +	barrier(); \
>> +	__atomic_thread_fence(__ATOMIC_RELEASE); \
>> +} while (0)
>> +
>> +#define smp_acquire() do { \
>> +	__atomic_thread_fence(__ATOMIC_ACQUIRE); \
>> +	barrier(); \
>> +} while (0)
>> +
>> +#if defined(__i386__) || defined(__x86_64__)
>> +#define smp_wmb()		barrier()
>> +#else
>> +#define smp_wmb()		smp_release()
>> +#endif
>> +
>> +#define READ_ONCE(x)		(*(volatile typeof(x) *)&(x))
>> +#define WRITE_ONCE(x, val)	((*(volatile typeof(x) *)&(x)) = (val))
>> +#define SMP_CACHE_BYTES		64
>> +#define cache_line_size		SMP_CACHE_BYTES
>> +#define unlikely(x)		(__builtin_expect(!!(x), 0))
>> +#define likely(x)		(__builtin_expect(!!(x), 1))
>> +#define ALIGN(x, a)		(((x) + (a) - 1) / (a) * (a))
>> +#define SIZE_MAX		(~(size_t)0)
>> +#define KMALLOC_MAX_SIZE	SIZE_MAX
>> +#define spinlock_t		pthread_spinlock_t
>> +#define gfp_t			int
>> +#define __GFP_ZERO		0x1
>> +
>> +#define ____cacheline_aligned_in_smp __attribute__((aligned(SMP_CACHE_BYTES)))
>> +
>> +static void *kmalloc(unsigned int size, gfp_t gfp)
>> +{
>> +	void *p;
>> +
>> +	p = memalign(64, size);
>> +	if (!p)
>> +		return p;
>> +
>> +	if (gfp & __GFP_ZERO)
>> +		memset(p, 0, size);
>> +
>> +	return p;
>> +}
>> +
>> +static inline void *kzalloc(unsigned int size, gfp_t flags)
>> +{
>> +	return kmalloc(size, flags | __GFP_ZERO);
>> +}
>> +
>> +static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
>> +{
>> +	if (size != 0 && n > SIZE_MAX / size)
>> +		return NULL;
>> +	return kmalloc(n * size, flags);
>> +}
>> +
>> +static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
>> +{
>> +	return kmalloc_array(n, size, flags | __GFP_ZERO);
>> +}
>> +
>> +static void kfree(void *p)
>> +{
>> +	free(p);
>> +}
>> +
>> +#define kvmalloc_array		kmalloc_array
>> +#define kvfree			kfree
>> +
>> +static void spin_lock_init(spinlock_t *lock)
>> +{
>> +	int r = pthread_spin_init(lock, 0);
>> +
>> +	assert(!r);
>> +}
>> +
>> +static void spin_lock(spinlock_t *lock)
>> +{
>> +	int ret = pthread_spin_lock(lock);
>> +
>> +	assert(!ret);
>> +}
>> +
>> +static void spin_unlock(spinlock_t *lock)
>> +{
>> +	int ret = pthread_spin_unlock(lock);
>> +
>> +	assert(!ret);
>> +}
>> +
>> +static void spin_lock_bh(spinlock_t *lock)
>> +{
>> +	spin_lock(lock);
>> +}
>> +
>> +static void spin_unlock_bh(spinlock_t *lock)
>> +{
>> +	spin_unlock(lock);
>> +}
>> +
>> +static void spin_lock_irq(spinlock_t *lock)
>> +{
>> +	spin_lock(lock);
>> +}
>> +
>> +static void spin_unlock_irq(spinlock_t *lock)
>> +{
>> +	spin_unlock(lock);
>> +}
>> +
>> +static void spin_lock_irqsave(spinlock_t *lock, unsigned long f)
>> +{
>> +	spin_lock(lock);
>> +}
>> +
>> +static void spin_unlock_irqrestore(spinlock_t *lock, unsigned long f)
>> +{
>> +	spin_unlock(lock);
>> +}
>> +
>> +#endif
>> -- 
>> 2.7.4
> 
> 
> .
> 

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