Recent changes (master)

[Jens Axboe <axboe@kernel.dk>]

The following changes since commit 46961748140e291f0f1e966bac9aad1a3b9ad1c7:

  engines/libaio: increase RLIMIT_MEMLOCK for user buffers (2018-12-04 11:27:02 -0700)

are available in the Git repository at:

  git://git.kernel.dk/fio.git master

for you to fetch changes up to 0527b23f9112b59dc63f3b40a7f40d45c48ec60d:

  t/aio-ring: updates/cleanups (2018-12-10 15:14:36 -0700)

----------------------------------------------------------------
Jens Axboe (2):
      Add aio-ring test app
      t/aio-ring: updates/cleanups

 Makefile     |   7 +
 t/aio-ring.c | 424 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 431 insertions(+)
 create mode 100644 t/aio-ring.c

---

Diff of recent changes:

diff --git a/Makefile b/Makefile
index 5ac568e9..284621d3 100644
--- a/Makefile
+++ b/Makefile
@@ -263,6 +263,9 @@ T_VS_PROGS = t/fio-verify-state
 T_PIPE_ASYNC_OBJS = t/read-to-pipe-async.o
 T_PIPE_ASYNC_PROGS = t/read-to-pipe-async
 
+T_AIO_RING_OBJS = t/aio-ring.o
+T_AIO_RING_PROGS = t/aio-ring
+
 T_MEMLOCK_OBJS = t/memlock.o
 T_MEMLOCK_PROGS = t/memlock
 
@@ -281,6 +284,7 @@ T_OBJS += $(T_VS_OBJS)
 T_OBJS += $(T_PIPE_ASYNC_OBJS)
 T_OBJS += $(T_MEMLOCK_OBJS)
 T_OBJS += $(T_TT_OBJS)
+T_OBJS += $(T_AIO_RING_OBJS)
 
 ifneq (,$(findstring CYGWIN,$(CONFIG_TARGET_OS)))
     T_DEDUPE_OBJS += os/windows/posix.o lib/hweight.o
@@ -440,6 +444,9 @@ cairo_text_helpers.o: cairo_text_helpers.c cairo_text_helpers.h
 printing.o: printing.c printing.h
 	$(QUIET_CC)$(CC) $(CFLAGS) $(GTK_CFLAGS) $(CPPFLAGS) -c $<
 
+t/aio-ring: $(T_AIO_RING_OBJS)
+	$(QUIET_LINK)$(CC) $(LDFLAGS) $(CFLAGS) -o $@ $(T_AIO_RING_OBJS) $(LIBS)
+
 t/read-to-pipe-async: $(T_PIPE_ASYNC_OBJS)
 	$(QUIET_LINK)$(CC) $(LDFLAGS) $(CFLAGS) -o $@ $(T_PIPE_ASYNC_OBJS) $(LIBS)
 
diff --git a/t/aio-ring.c b/t/aio-ring.c
new file mode 100644
index 00000000..c6106348
--- /dev/null
+++ b/t/aio-ring.c
@@ -0,0 +1,424 @@
+/*
+ * gcc -D_GNU_SOURCE -Wall -O2 -o aio-ring aio-ring.c  -lpthread -laio
+ */
+#include <stdio.h>
+#include <errno.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <signal.h>
+#include <inttypes.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/syscall.h>
+#include <sys/resource.h>
+#include <linux/fs.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <libaio.h>
+#include <string.h>
+#include <pthread.h>
+#include <sched.h>
+
+#define IOCB_FLAG_HIPRI		(1 << 2)
+
+#define IOCTX_FLAG_IOPOLL	(1 << 1)
+#define IOCTX_FLAG_USERIOCB	(1 << 0)
+#define IOCTX_FLAG_FIXEDBUFS	(1 << 2)
+#define IOCTX_FLAG_SCQRING	(1 << 3)	/* Use SQ/CQ rings */
+#define IOCTX_FLAG_SQTHREAD	(1 << 4)	/* Use SQ thread */
+#define IOCTX_FLAG_SQWQ		(1 << 5)	/* Use SQ wq */
+
+#define barrier()	__asm__ __volatile__("": : :"memory")
+
+#define min(a, b)		((a < b) ? (a) : (b))
+
+typedef uint32_t u32;
+
+struct aio_iocb_ring {
+	union {
+		struct {
+			u32 head, tail;
+			u32 nr_events;
+			u32 sq_thread_cpu;
+		};
+		struct iocb pad_iocb;
+	};
+	struct iocb iocbs[0];
+};
+
+struct aio_io_event_ring {
+	union {
+		struct {
+			u32 head, tail;
+			u32 nr_events;
+		};
+		struct io_event pad_event;
+	};
+	struct io_event events[0];
+};
+
+#define IORING_FLAG_SUBMIT	(1 << 0)
+#define IORING_FLAG_GETEVENTS	(1 << 1)
+
+#define DEPTH			32
+#define RING_SIZE		(DEPTH + 1)
+
+#define BATCH_SUBMIT		8
+#define BATCH_COMPLETE		8
+
+#define BS			4096
+
+struct submitter {
+	pthread_t thread;
+	unsigned long max_blocks;
+	io_context_t ioc;
+	struct drand48_data rand;
+	struct aio_iocb_ring *sq_ring;
+	struct aio_io_event_ring *cq_ring;
+	int inflight;
+	unsigned long reaps;
+	unsigned long done;
+	unsigned long calls;
+	volatile int finish;
+	char filename[128];
+};
+
+static struct submitter submitters[1];
+static volatile int finish;
+
+static int polled = 1;		/* use IO polling */
+static int fixedbufs = 1;	/* use fixed user buffers */
+static int buffered = 0;	/* use buffered IO, not O_DIRECT */
+static int sq_thread = 0;	/* use kernel submission thread */
+static int sq_thread_cpu = 0;	/* pin above thread to this CPU */
+
+static int io_setup2(unsigned int nr_events, unsigned int flags,
+		     struct iocb *iocbs, struct aio_iocb_ring *sq_ring,
+		     struct aio_io_event_ring *cq_ring, io_context_t *ctx_idp)
+{
+	return syscall(335, nr_events, flags, iocbs, sq_ring, cq_ring, ctx_idp);
+}
+
+static int io_ring_enter(io_context_t ctx, unsigned int to_submit,
+			 unsigned int min_complete, unsigned int flags)
+{
+	return syscall(336, ctx, to_submit, min_complete, flags);
+}
+
+static int gettid(void)
+{
+	return syscall(__NR_gettid);
+}
+
+static void init_io(struct submitter *s, int fd, struct iocb *iocb)
+{
+	unsigned long offset;
+	long r;
+
+	lrand48_r(&s->rand, &r);
+	offset = (r % (s->max_blocks - 1)) * BS;
+
+	iocb->aio_fildes = fd;
+	iocb->aio_lio_opcode = IO_CMD_PREAD;
+	iocb->u.c.offset = offset;
+	if (polled)
+		iocb->u.c.flags = IOCB_FLAG_HIPRI;
+	if (!fixedbufs)
+		iocb->u.c.nbytes = BS;
+}
+
+static int prep_more_ios(struct submitter *s, int fd, int max_ios)
+{
+	struct aio_iocb_ring *ring = s->sq_ring;
+	struct iocb *iocb;
+	u32 tail, next_tail, prepped = 0;
+
+	next_tail = tail = ring->tail;
+	do {
+		next_tail++;
+		if (next_tail == ring->nr_events)
+			next_tail = 0;
+
+		barrier();
+		if (next_tail == ring->head)
+			break;
+
+		iocb = &s->sq_ring->iocbs[tail];
+		init_io(s, fd, iocb);
+		prepped++;
+		tail = next_tail;
+	} while (prepped < max_ios);
+
+	if (ring->tail != tail) {
+		/* order tail store with writes to iocbs above */
+		barrier();
+		ring->tail = tail;
+		barrier();
+	}
+	return prepped;
+}
+
+static int get_file_size(int fd, unsigned long *blocks)
+{
+	struct stat st;
+
+	if (fstat(fd, &st) < 0)
+		return -1;
+	if (S_ISBLK(st.st_mode)) {
+		unsigned long long bytes;
+
+		if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
+			return -1;
+
+		*blocks = bytes / BS;
+		return 0;
+	} else if (S_ISREG(st.st_mode)) {
+		*blocks = st.st_size / BS;
+		return 0;
+	}
+
+	return -1;
+}
+
+static int reap_events(struct submitter *s)
+{
+	struct aio_io_event_ring *ring = s->cq_ring;
+	struct io_event *ev;
+	u32 head, reaped = 0;
+
+	head = ring->head;
+	do {
+		barrier();
+		if (head == ring->tail)
+			break;
+		ev = &ring->events[head];
+		if (ev->res != BS) {
+			int index = (int) (uintptr_t) ev->obj;
+			struct iocb *iocb = &s->sq_ring->iocbs[index];
+
+			printf("io: unexpected ret=%ld\n", ev->res);
+			printf("offset=%lu, size=%lu\n", (unsigned long) iocb->u.c.offset, (unsigned long) iocb->u.c.nbytes);
+			return -1;
+		}
+		reaped++;
+		head++;
+		if (head == ring->nr_events)
+			head = 0;
+	} while (1);
+
+	s->inflight -= reaped;
+	ring->head = head;
+	barrier();
+	return reaped;
+}
+
+static void *submitter_fn(void *data)
+{
+	struct submitter *s = data;
+	int fd, ret, prepped, flags;
+
+	printf("submitter=%d\n", gettid());
+
+	flags = O_RDONLY;
+	if (!buffered)
+		flags |= O_DIRECT;
+	fd = open(s->filename, flags);
+	if (fd < 0) {
+		perror("open");
+		goto done;
+	}
+
+	if (get_file_size(fd, &s->max_blocks)) {
+		printf("failed getting size of device/file\n");
+		goto err;
+	}
+	if (!s->max_blocks) {
+		printf("Zero file/device size?\n");
+		goto err;
+	}
+
+	s->max_blocks--;
+
+	srand48_r(pthread_self(), &s->rand);
+
+	prepped = 0;
+	do {
+		int to_wait, flags, to_submit, this_reap;
+
+		if (!prepped && s->inflight < DEPTH)
+			prepped = prep_more_ios(s, fd, min(DEPTH - s->inflight, BATCH_SUBMIT));
+		s->inflight += prepped;
+submit_more:
+		to_submit = prepped;
+submit:
+		if (s->inflight + BATCH_SUBMIT < DEPTH)
+			to_wait = 0;
+		else
+			to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
+
+		flags = IORING_FLAG_GETEVENTS;
+		if (to_submit)
+			flags |= IORING_FLAG_SUBMIT;
+
+		ret = io_ring_enter(s->ioc, to_submit, to_wait, flags);
+		s->calls++;
+
+		this_reap = reap_events(s);
+		if (this_reap == -1)
+			break;
+		s->reaps += this_reap;
+
+		if (ret >= 0) {
+			if (!ret) {
+				to_submit = 0;
+				if (s->inflight)
+					goto submit;
+				continue;
+			} else if (ret < to_submit) {
+				int diff = to_submit - ret;
+
+				s->done += ret;
+				prepped -= diff;
+				goto submit_more;
+			}
+			s->done += ret;
+			prepped = 0;
+			continue;
+		} else if (ret < 0) {
+			if ((ret == -1 && errno == EAGAIN) || ret == -EAGAIN) {
+				if (s->finish)
+					break;
+				if (this_reap)
+					goto submit;
+				to_submit = 0;
+				goto submit;
+			}
+			if (ret == -1)
+				printf("io_submit: %s\n", strerror(errno));
+			else
+				printf("io_submit: %s\n", strerror(-ret));
+			break;
+		}
+	} while (!s->finish);
+err:
+	close(fd);
+done:
+	finish = 1;
+	return NULL;
+}
+
+static void sig_int(int sig)
+{
+	printf("Exiting on signal %d\n", sig);
+	submitters[0].finish = 1;
+	finish = 1;
+}
+
+static void arm_sig_int(void)
+{
+	struct sigaction act;
+
+	memset(&act, 0, sizeof(act));
+	act.sa_handler = sig_int;
+	act.sa_flags = SA_RESTART;
+	sigaction(SIGINT, &act, NULL);
+}
+
+int main(int argc, char *argv[])
+{
+	struct submitter *s = &submitters[0];
+	unsigned long done, calls, reap;
+	int flags = 0, err;
+	int j;
+	size_t size;
+	void *p, *ret;
+	struct rlimit rlim;
+
+	if (argc < 2) {
+		printf("%s: filename\n", argv[0]);
+		return 1;
+	}
+
+	rlim.rlim_cur = RLIM_INFINITY;
+	rlim.rlim_max = RLIM_INFINITY;
+	if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
+		perror("setrlimit");
+		return 1;
+	}
+
+	arm_sig_int();
+
+	size = sizeof(struct aio_iocb_ring) + RING_SIZE * sizeof(struct iocb);
+	if (posix_memalign(&p, 4096, size))
+		return 1;
+	s->sq_ring = p;
+	memset(p, 0, size);
+
+	size = sizeof(struct aio_io_event_ring) + RING_SIZE * sizeof(struct io_event);
+	if (posix_memalign(&p, 4096, size))
+		return 1;
+	s->cq_ring = p;
+	memset(p, 0, size);
+
+	for (j = 0; j < RING_SIZE; j++) {
+		struct iocb *iocb = &s->sq_ring->iocbs[j];
+
+		if (posix_memalign(&iocb->u.c.buf, BS, BS)) {
+			printf("failed alloc\n");
+			return 1;
+		}
+		iocb->u.c.nbytes = BS;
+	}
+
+	flags = IOCTX_FLAG_SCQRING;
+	if (polled)
+		flags |= IOCTX_FLAG_IOPOLL;
+	if (fixedbufs)
+		flags |= IOCTX_FLAG_FIXEDBUFS;
+	if (buffered)
+		flags |= IOCTX_FLAG_SQWQ;
+	else if (sq_thread) {
+		flags |= IOCTX_FLAG_SQTHREAD;
+		s->sq_ring->sq_thread_cpu = sq_thread_cpu;
+	}
+
+	err = io_setup2(RING_SIZE, flags, s->sq_ring->iocbs, s->sq_ring, s->cq_ring, &s->ioc);
+	if (err) {
+		printf("ctx_init failed: %s, %d\n", strerror(errno), err);
+		return 1;
+	}
+	printf("polled=%d, fixedbufs=%d, buffered=%d\n", polled, fixedbufs, buffered);
+	printf("  QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, s->sq_ring->nr_events, s->cq_ring->nr_events);
+	strcpy(s->filename, argv[1]);
+
+	pthread_create(&s->thread, NULL, submitter_fn, s);
+
+	reap = calls = done = 0;
+	do {
+		unsigned long this_done = 0;
+		unsigned long this_reap = 0;
+		unsigned long this_call = 0;
+		unsigned long rpc = 0, ipc = 0;
+
+		sleep(1);
+		this_done += s->done;
+		this_call += s->calls;
+		this_reap += s->reaps;
+		if (this_call - calls) {
+			rpc = (this_done - done) / (this_call - calls);
+			ipc = (this_reap - reap) / (this_call - calls);
+		}
+		printf("IOPS=%lu, IOS/call=%lu/%lu, inflight=%u (head=%d tail=%d), %lu, %lu\n",
+				this_done - done, rpc, ipc, s->inflight,
+				s->cq_ring->head, s->cq_ring->tail, s->reaps, s->done);
+		done = this_done;
+		calls = this_call;
+		reap = this_reap;
+	} while (!finish);
+
+	pthread_join(s->thread, &ret);
+	return 0;
+}