Recent changes (master)

Jens Axboe
2018-12-11T13:00:16Z

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;
+}