Hi again,
I have good news, I finally solved my problem !
Simply with installing irqbalance
#apt-get install irqbalance
So maybe the problem was at the nic/network level.
Now : 3.18 kernel + your patch : 120000 iops
3.10 kernel : 80000iops
I'll try 3.18 kernel without your patch to compare.
----- Mail original -----
De: "Alexandre DERUMIER" <aderumier@xxxxxxxxx>
À: "Christoph Hellwig" <hch@xxxxxxxxxxxxx>
Cc: "Ceph Devel" <ceph-devel@xxxxxxxxxxxxxxx>
Envoyé: Mardi 4 Novembre 2014 07:57:19
Objet: Re: krbd blk-mq support ?
Hi Christoph,
I had tried your patch, but no improvement for my problem.
I have always a kworker near 100% on 1core.
I have finally be able to do perf on 3.18 kernel + your patch, I have attached the report in this mail.
----- Mail original -----
De: "Christoph Hellwig" <hch@xxxxxxxxxxxxx>
À: "Alexandre DERUMIER" <aderumier@xxxxxxxxx>
Cc: "Christoph Hellwig" <hch@xxxxxxxxxxxxx>, "Ceph Devel" <ceph-devel@xxxxxxxxxxxxxxx>
Envoyé: Lundi 3 Novembre 2014 12:08:07
Objet: Re: krbd blk-mq support ?
Hi Alexandre,
can you try the patch below instead of the previous three patches?
This one uses a per-request work struct to allow for more concurrency.
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 0a54c58..b981096 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -38,6 +38,7 @@
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/module.h>
+#include <linux/blk-mq.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
@@ -343,7 +344,6 @@ struct rbd_device {
struct list_head rq_queue; /* incoming rq queue */
spinlock_t lock; /* queue, flags, open_count */
struct workqueue_struct *rq_wq;
- struct work_struct rq_work;
struct rbd_image_header header;
unsigned long flags; /* possibly lock protected */
@@ -361,6 +361,9 @@ struct rbd_device {
atomic_t parent_ref;
struct rbd_device *parent;
+ /* Block layer tags. */
+ struct blk_mq_tag_set tag_set;
+
/* protects updating the header */
struct rw_semaphore header_rwsem;
@@ -1816,7 +1819,8 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
/*
* We support a 64-bit length, but ultimately it has to be
- * passed to blk_end_request(), which takes an unsigned int.
+ * passed to the block layer, which just supports a 32-bit
+ * length field.
*/
obj_request->xferred = osd_req->r_reply_op_len[0];
rbd_assert(obj_request->xferred < (u64)UINT_MAX);
@@ -2280,7 +2284,10 @@ static bool rbd_img_obj_end_request(struct rbd_obj_request *obj_request)
more = obj_request->which < img_request->obj_request_count - 1;
} else {
rbd_assert(img_request->rq != NULL);
- more = blk_end_request(img_request->rq, result, xferred);
+
+ more = blk_update_request(img_request->rq, result, xferred);
+ if (!more)
+ __blk_mq_end_request(img_request->rq, result);
}
return more;
@@ -3305,8 +3312,10 @@ out:
return ret;
}
-static void rbd_handle_request(struct rbd_device *rbd_dev, struct request *rq)
+static void rbd_queue_workfn(struct work_struct *work)
{
+ struct request *rq = blk_mq_rq_from_pdu(work);
+ struct rbd_device *rbd_dev = rq->q->queuedata;
struct rbd_img_request *img_request;
struct ceph_snap_context *snapc = NULL;
u64 offset = (u64)blk_rq_pos(rq) << SECTOR_SHIFT;
@@ -3314,6 +3323,13 @@ static void rbd_handle_request(struct rbd_device *rbd_dev, struct request *rq)
enum obj_operation_type op_type;
u64 mapping_size;
int result;
+
+ if (rq->cmd_type != REQ_TYPE_FS) {
+ dout("%s: non-fs request type %d\n", __func__,
+ (int) rq->cmd_type);
+ result = -EIO;
+ goto err;
+ }
if (rq->cmd_flags & REQ_DISCARD)
op_type = OBJ_OP_DISCARD;
@@ -3353,6 +3369,8 @@ static void rbd_handle_request(struct rbd_device *rbd_dev, struct request *rq)
goto err_rq;
}
+ blk_mq_start_request(rq);
+
if (offset && length > U64_MAX - offset + 1) {
rbd_warn(rbd_dev, "bad request range (%llu~%llu)", offset,
length);
@@ -3406,53 +3424,18 @@ err_rq:
obj_op_name(op_type), length, offset, result);
if (snapc)
ceph_put_snap_context(snapc);
- blk_end_request_all(rq, result);
+err:
+ blk_mq_end_request(rq, result);
}
-static void rbd_request_workfn(struct work_struct *work)
+static int rbd_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq,
+ bool last)
{
- struct rbd_device *rbd_dev =
- container_of(work, struct rbd_device, rq_work);
- struct request *rq, *next;
- LIST_HEAD(requests);
-
- spin_lock_irq(&rbd_dev->lock); /* rq->q->queue_lock */
- list_splice_init(&rbd_dev->rq_queue, &requests);
- spin_unlock_irq(&rbd_dev->lock);
-
- list_for_each_entry_safe(rq, next, &requests, queuelist) {
- list_del_init(&rq->queuelist);
- rbd_handle_request(rbd_dev, rq);
- }
-}
+ struct rbd_device *rbd_dev = rq->q->queuedata;
+ struct work_struct *work = blk_mq_rq_to_pdu(rq);
-/*
- * Called with q->queue_lock held and interrupts disabled, possibly on
- * the way to schedule(). Do not sleep here!
- */
-static void rbd_request_fn(struct request_queue *q)
-{
- struct rbd_device *rbd_dev = q->queuedata;
- struct request *rq;
- int queued = 0;
-
- rbd_assert(rbd_dev);
-
- while ((rq = blk_fetch_request(q))) {
- /* Ignore any non-FS requests that filter through. */
- if (rq->cmd_type != REQ_TYPE_FS) {
- dout("%s: non-fs request type %d\n", __func__,
- (int) rq->cmd_type);
- __blk_end_request_all(rq, 0);
- continue;
- }
-
- list_add_tail(&rq->queuelist, &rbd_dev->rq_queue);
- queued++;
- }
-
- if (queued)
- queue_work(rbd_dev->rq_wq, &rbd_dev->rq_work);
+ queue_work(rbd_dev->rq_wq, work);
+ return 0;
}
/*
@@ -3513,6 +3496,7 @@ static void rbd_free_disk(struct rbd_device *rbd_dev)
del_gendisk(disk);
if (disk->queue)
blk_cleanup_queue(disk->queue);
+ blk_mq_free_tag_set(&rbd_dev->tag_set);
}
put_disk(disk);
}
@@ -3724,11 +3708,28 @@ static int rbd_dev_refresh(struct rbd_device *rbd_dev)
return 0;
}
+static int rbd_init_request(void *data, struct request *rq,
+ unsigned int hctx_idx, unsigned int request_idx,
+ unsigned int numa_node)
+{
+ struct work_struct *work = blk_mq_rq_to_pdu(rq);
+
+ INIT_WORK(work, rbd_queue_workfn);
+ return 0;
+}
+
+static struct blk_mq_ops rbd_mq_ops = {
+ .queue_rq = rbd_queue_rq,
+ .map_queue = blk_mq_map_queue,
+ .init_request = rbd_init_request,
+};
+
static int rbd_init_disk(struct rbd_device *rbd_dev)
{
struct gendisk *disk;
struct request_queue *q;
u64 segment_size;
+ int err;
/* create gendisk info */
disk = alloc_disk(single_major ?
@@ -3746,10 +3747,24 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
disk->fops = &rbd_bd_ops;
disk->private_data = rbd_dev;
- q = blk_init_queue(rbd_request_fn, &rbd_dev->lock);
- if (!q)
+ memset(&rbd_dev->tag_set, 0, sizeof(rbd_dev->tag_set));
+ rbd_dev->tag_set.ops = &rbd_mq_ops;
+ rbd_dev->tag_set.queue_depth = 128; //
+ rbd_dev->tag_set.numa_node = NUMA_NO_NODE;
+ rbd_dev->tag_set.flags =
+ BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ rbd_dev->tag_set.nr_hw_queues = 1;
+ rbd_dev->tag_set.cmd_size = sizeof(struct work_struct);
+
+ err = blk_mq_alloc_tag_set(&rbd_dev->tag_set);
+ if (err)
goto out_disk;
+ err = -ENOMEM;
+ q = blk_mq_init_queue(&rbd_dev->tag_set);
+ if (!q)
+ goto out_tag_set;
+
/* We use the default size, but let's be explicit about it. */
blk_queue_physical_block_size(q, SECTOR_SIZE);
@@ -3775,10 +3790,11 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
rbd_dev->disk = disk;
return 0;
+out_tag_set:
+ blk_mq_free_tag_set(&rbd_dev->tag_set);
out_disk:
put_disk(disk);
-
- return -ENOMEM;
+ return err;
}
/*
@@ -4036,7 +4052,6 @@ static struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,
spin_lock_init(&rbd_dev->lock);
INIT_LIST_HEAD(&rbd_dev->rq_queue);
- INIT_WORK(&rbd_dev->rq_work, rbd_request_workfn);
rbd_dev->flags = 0;
atomic_set(&rbd_dev->parent_ref, 0);
INIT_LIST_HEAD(&rbd_dev->node);
--
1.9.1
--
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