Commit 3f5b1169 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

selftests: ublk: make ublk_thread thread-local variable 



Refactor ublk_thread to be a thread-local variable instead of storing
it in ublk_dev:

- Remove pthread_t thread field from struct ublk_thread and move it to
  struct ublk_thread_info

- Remove struct ublk_thread array from struct ublk_dev, reducing memory
  footprint

- Define struct ublk_thread as local variable in __ublk_io_handler_fn()
  instead of accessing it from dev->threads[]

- Extract main IO handling logic into __ublk_io_handler_fn() which is
  marked as noinline

- Move CPU affinity setup to ublk_io_handler_fn() before calling
  __ublk_io_handler_fn()

- Update ublk_thread_set_sched_affinity() to take struct ublk_thread_info *
  instead of struct ublk_thread *, and use pthread_setaffinity_np()
  instead of sched_setaffinity()

- Reorder struct ublk_thread fields to group related state together

This change makes each thread's ublk_thread structure truly local to
the thread, improving cache locality and reducing memory usage.

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0123bb91

tools/testing/selftests/ublk/kublk.c

+42 −34
Original line number Diff line number Diff line
@@ -836,62 +836,70 @@ static int ublk_process_io(struct ublk_thread *t) 
	return reapped;

}



static void ublk_thread_set_sched_affinity(const struct ublk_thread *t,

		cpu_set_t *cpuset)

{

	if (pthread_setaffinity_np(pthread_self(), sizeof(*cpuset), cpuset) < 0)

		ublk_err("ublk dev %u thread %u set affinity failed",

				t->dev->dev_info.dev_id, t->idx);

}



struct ublk_thread_info {

	struct ublk_dev 	*dev;

	pthread_t		thread;

	unsigned		idx;

	sem_t 			*ready;

	cpu_set_t 		*affinity;

	unsigned long long	extra_flags;

};



static void *ublk_io_handler_fn(void *data)

static void ublk_thread_set_sched_affinity(const struct ublk_thread_info *info)

{

	struct ublk_thread_info *info = data;

	struct ublk_thread *t = &info->dev->threads[info->idx];

	if (pthread_setaffinity_np(pthread_self(), sizeof(*info->affinity), info->affinity) < 0)

		ublk_err("ublk dev %u thread %u set affinity failed",

				info->dev->dev_info.dev_id, info->idx);

}



static __attribute__((noinline)) int __ublk_io_handler_fn(struct ublk_thread_info *info)

{

	struct ublk_thread t = {

		.dev = info->dev,

		.idx = info->idx,

	};

	int dev_id = info->dev->dev_info.dev_id;

	int ret;



	t->dev = info->dev;

	t->idx = info->idx;



	/*

	 * IO perf is sensitive with queue pthread affinity on NUMA machine

	 *

	 * Set sched_affinity at beginning, so following allocated memory/pages

	 * could be CPU/NUMA aware.

	 */

	if (info->affinity)

		ublk_thread_set_sched_affinity(t, info->affinity);



	ret = ublk_thread_init(t, info->extra_flags);

	ret = ublk_thread_init(&t, info->extra_flags);

	if (ret) {

		ublk_err("ublk dev %d thread %u init failed\n",

				dev_id, t->idx);

		return NULL;

				dev_id, t.idx);

		return ret;

	}

	sem_post(info->ready);



	ublk_dbg(UBLK_DBG_THREAD, "tid %d: ublk dev %d thread %u started\n",

			gettid(), dev_id, t->idx);

			gettid(), dev_id, t.idx);



	/* submit all io commands to ublk driver */

	ublk_submit_fetch_commands(t);

	ublk_submit_fetch_commands(&t);

	do {

		if (ublk_process_io(t) < 0)

		if (ublk_process_io(&t) < 0)

			break;

	} while (1);



	ublk_dbg(UBLK_DBG_THREAD, "tid %d: ublk dev %d thread %d exiting\n",

		 gettid(), dev_id, t->idx);

	ublk_thread_deinit(t);

		 gettid(), dev_id, t.idx);

	ublk_thread_deinit(&t);

	return 0;

}



static void *ublk_io_handler_fn(void *data)

{

	struct ublk_thread_info *info = data;



	/*

	 * IO perf is sensitive with queue pthread affinity on NUMA machine

	 *

	 * Set sched_affinity at beginning, so following allocated memory/pages

	 * could be CPU/NUMA aware.

	 */

	if (info->affinity)

		ublk_thread_set_sched_affinity(info);



	__ublk_io_handler_fn(info);



	return NULL;

}
@@ -989,14 +997,13 @@ static int ublk_start_daemon(const struct dev_ctx *ctx, struct ublk_dev *dev) 
		 */

		if (dev->nthreads == dinfo->nr_hw_queues)

			tinfo[i].affinity = &affinity_buf[i];

		pthread_create(&dev->threads[i].thread, NULL,

		pthread_create(&tinfo[i].thread, NULL,

				ublk_io_handler_fn,

				&tinfo[i]);

	}



	for (i = 0; i < dev->nthreads; i++)

		sem_wait(&ready);

	free(tinfo);

	free(affinity_buf);



	/* everything is fine now, start us */
@@ -1019,7 +1026,8 @@ static int ublk_start_daemon(const struct dev_ctx *ctx, struct ublk_dev *dev) 


	/* wait until we are terminated */

	for (i = 0; i < dev->nthreads; i++)

		pthread_join(dev->threads[i].thread, &thread_ret);

		pthread_join(tinfo[i].thread, &thread_ret);

	free(tinfo);

 fail:

	for (i = 0; i < dinfo->nr_hw_queues; i++)

		ublk_queue_deinit(&dev->q[i]);

tools/testing/selftests/ublk/kublk.h

+3 −6
Original line number Diff line number Diff line
@@ -175,23 +175,20 @@ struct ublk_queue { 


struct ublk_thread {

	struct ublk_dev *dev;

	struct io_uring ring;

	unsigned int cmd_inflight;

	unsigned int io_inflight;



	pthread_t thread;

	unsigned idx;



#define UBLKS_T_STOPPING	(1U << 0)

#define UBLKS_T_IDLE	(1U << 1)

	unsigned state;

	unsigned int cmd_inflight;

	unsigned int io_inflight;

	struct io_uring ring;

};



struct ublk_dev {

	struct ublk_tgt tgt;

	struct ublksrv_ctrl_dev_info  dev_info;

	struct ublk_queue q[UBLK_MAX_QUEUES];

	struct ublk_thread threads[UBLK_MAX_THREADS];

	unsigned nthreads;

	unsigned per_io_tasks;