X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=engines%2Fsyslet-rw.c;h=0fdf75227295540de9defc4976a8b2a84dfb8957;hb=f3de88a7a8806016ebb27af3f4be1fced172122e;hp=8a1ab4f0c253edcc16f8aa1dc638c59c11cbe58a;hpb=12cbb469ea5e559b241f6c31693554829e8b8400;p=fio.git

diff --git a/engines/syslet-rw.c b/engines/syslet-rw.c
index 8a1ab4f0..0fdf7522 100644
--- a/engines/syslet-rw.c
+++ b/engines/syslet-rw.c
@@ -14,8 +14,7 @@
 #include <asm/unistd.h>
 
 #include "../fio.h"
-#include "../indirect.h"
-#include "../syslet.h"
+#include "../fls.h"
 
 #ifdef FIO_HAVE_SYSLET
 
@@ -32,10 +31,11 @@ struct syslet_data {
 	unsigned int nr_events;
 	
 	struct syslet_ring *ring;
+	unsigned int ring_mask;
 	void *stack;
 };
 
-static void fio_syslet_complete(struct thread_data *td, struct io_u *io_u)
+static void fio_syslet_add_event(struct thread_data *td, struct io_u *io_u)
 {
 	struct syslet_data *sd = td->io_ops->data;
 
@@ -43,29 +43,38 @@ static void fio_syslet_complete(struct thread_data *td, struct io_u *io_u)
 	sd->events[sd->nr_events++] = io_u;
 }
 
-static void syslet_complete_nr(struct thread_data *td, unsigned int nr)
+static void fio_syslet_add_events(struct thread_data *td, unsigned int nr)
 {
 	struct syslet_data *sd = td->io_ops->data;
-	unsigned int i;
+	unsigned int i, uidx;
+
+	uidx = sd->ring->user_tail;
+	read_barrier();
 
 	for (i = 0; i < nr; i++) {
-		unsigned int idx = (i + sd->ring->user_tail) % td->o.iodepth;
+		unsigned int idx = (i + uidx) & sd->ring_mask;
 		struct syslet_completion *comp = &sd->ring->comp[idx];
 		struct io_u *io_u = (struct io_u *) (long) comp->caller_data;
+		long ret;
+
+		ret = comp->status;
+		if (ret <= 0) {
+			io_u->resid = io_u->xfer_buflen;
+			io_u->error = -ret;
+		} else {
+			io_u->resid = io_u->xfer_buflen - ret;
+			io_u->error = 0;
+		}
 
-		io_u->resid = io_u->xfer_buflen - comp->status;
-		fio_syslet_complete(td, io_u);
+		fio_syslet_add_event(td, io_u);
 	}
 }
 
-
 static void fio_syslet_wait_for_events(struct thread_data *td)
 {
 	struct syslet_data *sd = td->io_ops->data;
 	struct syslet_ring *ring = sd->ring;
-	unsigned int events;
 
-	events = 0;
 	do {
 		unsigned int kh = ring->kernel_head;
 		int ret;
@@ -76,10 +85,9 @@ static void fio_syslet_wait_for_events(struct thread_data *td)
 		if (ring->user_tail != kh) {
 			unsigned int nr = kh - ring->user_tail;
 
-			syslet_complete_nr(td, nr);
-			events += nr;
+			fio_syslet_add_events(td, nr);
 			ring->user_tail = kh;
-			continue;
+			break;
 		}
 
 		/*
@@ -87,25 +95,23 @@ static void fio_syslet_wait_for_events(struct thread_data *td)
 		 */
 		ret = syscall(__NR_syslet_ring_wait, ring, ring->user_tail);
 		assert(!ret);
-	} while (!events);
+	} while (1);
 }
 
-static int fio_syslet_getevents(struct thread_data *td, int min,
-				int fio_unused max,
+static int fio_syslet_getevents(struct thread_data *td, unsigned int min,
+				unsigned int fio_unused max,
 				struct timespec fio_unused *t)
 {
 	struct syslet_data *sd = td->io_ops->data;
 	long ret;
 
-	do {
-		/*
-		 * do we have enough immediate completions?
-		 */
-		if (sd->nr_events >= (unsigned int) min)
-			break;
-
+	/*
+	 * While we have less events than requested, block waiting for them
+	 * (if we have to, there may already be more completed events ready
+	 * for us - see fio_syslet_wait_for_events()
+	 */
+	while (sd->nr_events < min)
 		fio_syslet_wait_for_events(td);
-	} while (1);
 
 	ret = sd->nr_events;
 	sd->nr_events = 0;
@@ -215,7 +221,6 @@ static void fio_syslet_cleanup(struct thread_data *td)
 	if (sd) {
 		free(sd->events);
 		free(sd->ring);
-		free(sd->stack);
 		free(sd);
 		td->io_ops->data = NULL;
 	}
@@ -224,35 +229,50 @@ static void fio_syslet_cleanup(struct thread_data *td)
 static int fio_syslet_init(struct thread_data *td)
 {
 	struct syslet_data *sd;
-	void *ring, *stack;
+	void *ring = NULL, *stack = NULL;
+	unsigned int ring_size, ring_nr;
 
 	sd = malloc(sizeof(*sd));
 	memset(sd, 0, sizeof(*sd));
 
 	sd->events = malloc(sizeof(struct io_u *) * td->o.iodepth);
 	memset(sd->events, 0, sizeof(struct io_u *) * td->o.iodepth);
-	if (posix_memalign(&ring, sizeof(uint64_t), sizeof(struct syslet_ring)))
-		return 1;
+
+	/*
+	 * The ring needs to be a power-of-2, so round it up if we have to
+	 */
+	ring_nr = td->o.iodepth;
+	if (ring_nr & (ring_nr - 1))
+		ring_nr = 1 << fls(ring_nr);
+
+	ring_size = sizeof(struct syslet_ring) +
+			ring_nr * sizeof(struct syslet_completion);
+	if (posix_memalign(&ring, sizeof(uint64_t), ring_size))
+		goto err_mem;
 	if (posix_memalign(&stack, page_size, page_size))
-		return 1;
+		goto err_mem;
 
 	sd->ring = ring;
+	sd->ring_mask = ring_nr - 1;
 	sd->stack = stack;
 
-	memset(sd->ring, 0, sizeof(*sd->ring));
-	sd->ring->elements = td->o.iodepth;
+	memset(sd->ring, 0, ring_size);
+	sd->ring->elements = ring_nr;
 
-	if (check_syslet_support(sd)) {
-		log_err("fio: syslets do not appear to work\n");
-		free(sd->events);
-		free(sd->ring);
-		free(sd->stack);
-		free(sd);
-		return 1;
+	if (!check_syslet_support(sd)) {
+		td->io_ops->data = sd;
+		return 0;
 	}
 
-	td->io_ops->data = sd;
-	return 0;
+	log_err("fio: syslets do not appear to work\n");
+err_mem:
+	free(sd->events);
+	if (ring)
+		free(ring);
+	if (stack)
+		free(stack);
+	free(sd);
+	return 1;
 }
 
 static struct ioengine_ops ioengine = {