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RDMA/core: Provide RDMA DIM support for ULPs 

Added the interface in the infiniband driver that applies the rdma_dim
adaptive moderation. There is now a special function for allocating an
ib_cq that uses rdma_dim.

Performance improvement (ConnectX-5 100GbE, x86) running FIO benchmark over
NVMf between two equal end-hosts with 56 cores across a Mellanox switch
using null_blk device:

READS without DIM:
blk size | BW       | IOPS | 99th percentile latency  | 99.99th latency
512B     | 3.8GiB/s | 7.7M | 1401  usec               | 2442  usec
4k       | 7.0GiB/s | 1.8M | 4817  usec               | 6587  usec
64k      | 10.7GiB/s| 175k | 9896  usec               | 10028 usec

IO WRITES without DIM:
blk size | BW       | IOPS | 99th percentile latency  | 99.99th latency
512B     | 3.6GiB/s | 7.5M | 1434  usec               | 2474  usec
4k       | 6.3GiB/s | 1.6M | 938   usec               | 1221  usec
64k      | 10.7GiB/s| 175k | 8979  usec               | 12780 usec

IO READS with DIM:
blk size | BW       | IOPS | 99th percentile latency  | 99.99th latency
512B     | 4GiB/s   | 8.2M | 816    usec              | 889   usec
4k       | 10.1GiB/s| 2.65M| 3359   usec              | 5080  usec
64k      | 10.7GiB/s| 175k | 9896   usec              | 10028 usec

IO WRITES with DIM:
blk size | BW       | IOPS  | 99th percentile latency | 99.99th latency
512B     | 3.9GiB/s | 8.1M  | 799   usec              | 922   usec
4k       | 9.6GiB/s | 2.5M  | 717   usec              | 1004  usec
64k      | 10.7GiB/s| 176k  | 8586  usec              | 12256 usec

The rdma_dim algorithm was designed to measure the effectiveness of
moderation on the flow in a general way and thus should be appropriate
for all RDMA storage protocols.

rdma_dim is configured to be the default option based on performance
improvement seen after extensive tests.

Signed-off-by: Yamin Friedman <yaminf@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Yamin Friedman 2019-07-08 13:59:03 +03:00 committed by Jason Gunthorpe
parent f4915455dc
commit da6629793a
2 changed files with 49 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
drivers/infiniband/core/cq.c
View File

@ -18,6 +18,40 @@
#define IB_POLL_FLAGS \
(IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS)
static void ib_cq_rdma_dim_work(struct work_struct *w)
{
struct dim *dim = container_of(w, struct dim, work);
struct ib_cq *cq = dim->priv;
u16 usec = rdma_dim_prof[dim->profile_ix].usec;
u16 comps = rdma_dim_prof[dim->profile_ix].comps;
dim->state = DIM_START_MEASURE;
cq->device->ops.modify_cq(cq, comps, usec);
}
static void rdma_dim_init(struct ib_cq *cq)
{
struct dim *dim;
if (!cq->device->ops.modify_cq || !cq->device->use_cq_dim ||
cq->poll_ctx == IB_POLL_DIRECT)
return;
dim = kzalloc(sizeof(struct dim), GFP_KERNEL);
if (!dim)
return;
dim->state = DIM_START_MEASURE;
dim->tune_state = DIM_GOING_RIGHT;
dim->profile_ix = RDMA_DIM_START_PROFILE;
dim->priv = cq;
cq->dim = dim;
INIT_WORK(&dim->work, ib_cq_rdma_dim_work);
}
static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *wcs,
int batch)
{
@ -78,6 +112,7 @@ static void ib_cq_completion_direct(struct ib_cq *cq, void *private)
static int ib_poll_handler(struct irq_poll *iop, int budget)
{
struct ib_cq *cq = container_of(iop, struct ib_cq, iop);
struct dim *dim = cq->dim;
int completed;
completed = __ib_process_cq(cq, budget, cq->wc, IB_POLL_BATCH);
@ -87,6 +122,9 @@ static int ib_poll_handler(struct irq_poll *iop, int budget)
irq_poll_sched(&cq->iop);
}
if (dim)
rdma_dim(dim, completed);
return completed;
}
@ -105,6 +143,8 @@ static void ib_cq_poll_work(struct work_struct *work)
if (completed >= IB_POLL_BUDGET_WORKQUEUE ||
ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0)
queue_work(cq->comp_wq, &cq->work);
else if (cq->dim)
rdma_dim(cq->dim, completed);
}
static void ib_cq_completion_workqueue(struct ib_cq *cq, void *private)
@ -161,6 +201,8 @@ struct ib_cq *__ib_alloc_cq_user(struct ib_device *dev, void *private,
rdma_restrack_kadd(&cq->res);
rdma_dim_init(cq);
switch (cq->poll_ctx) {
case IB_POLL_DIRECT:
cq->comp_handler = ib_cq_completion_direct;
@ -223,6 +265,9 @@ void ib_free_cq_user(struct ib_cq *cq, struct ib_udata *udata)
rdma_restrack_del(&cq->res);
cq->device->ops.destroy_cq(cq, udata);
if (cq->dim)
cancel_work_sync(&cq->dim->work);
kfree(cq->dim);
kfree(cq->wc);
kfree(cq);
}

4
include/rdma/ib_verbs.h
View File

@ -61,6 +61,7 @@
#include <linux/cgroup_rdma.h>
#include <linux/irqflags.h>
#include <linux/preempt.h>
#include <linux/dim.h>
#include <uapi/rdma/ib_user_verbs.h>
#include <rdma/rdma_counter.h>
#include <rdma/restrack.h>
@ -1509,6 +1510,7 @@ struct ib_cq {
struct work_struct work;
};
struct workqueue_struct *comp_wq;
struct dim *dim;
/*
* Implementation details of the RDMA core, don't use in drivers:
*/
@ -2576,6 +2578,8 @@ struct ib_device {
u16 is_switch:1;
/* Indicates kernel verbs support, should not be used in drivers */
u16 kverbs_provider:1;
/* CQ adaptive moderation (RDMA DIM) */
u16 use_cq_dim:1;
u8 node_type;
u8 phys_port_cnt;
struct ib_device_attr attrs;