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.
Unified · Split
| @@ -18,6 +18,40 @@ · 17 unmodified lines | ||
| 18 | 18 | #define IB_POLL_FLAGS \ |
| 19 | 19 | (IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS) |
| 20 | 20 | |
| 21 | +static void ib_cq_rdma_dim_work(struct work_struct *w) | |
| 22 | +{ | |
| 23 | + struct dim *dim = container_of(w, struct dim, work); | |
| 24 | + struct ib_cq *cq = dim->priv; | |
| 25 | + | |
| 26 | + u16 usec = rdma_dim_prof[dim->profile_ix].usec; | |
| 27 | + u16 comps = rdma_dim_prof[dim->profile_ix].comps; | |
| 28 | + | |
| 29 | + dim->state = DIM_START_MEASURE; | |
| 30 | + | |
| 31 | + cq->device->ops.modify_cq(cq, comps, usec); | |
| 32 | +} | |
| 33 | + | |
| 34 | +static void rdma_dim_init(struct ib_cq *cq) | |
| 35 | +{ | |
| 36 | + struct dim *dim; | |
| 37 | + | |
| 38 | + if (!cq->device->ops.modify_cq || !cq->device->use_cq_dim || | |
| 39 | + cq->poll_ctx == IB_POLL_DIRECT) | |
| 40 | + return; | |
| 41 | + | |
| 42 | + dim = kzalloc(sizeof(struct dim), GFP_KERNEL); | |
| 43 | + if (!dim) | |
| 44 | + return; | |
| 45 | + | |
| 46 | + dim->state = DIM_START_MEASURE; | |
| 47 | + dim->tune_state = DIM_GOING_RIGHT; | |
| 48 | + dim->profile_ix = RDMA_DIM_START_PROFILE; | |
| 49 | + dim->priv = cq; | |
| 50 | + cq->dim = dim; | |
| 51 | + | |
| 52 | + INIT_WORK(&dim->work, ib_cq_rdma_dim_work); | |
| 53 | +} | |
| 54 | + | |
| 21 | 55 | static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *wcs, |
| 22 | 56 | int batch) |
| 23 | 57 | { |
| @@ -78,6 +112,7 @@ static void ib_cq_completion_direct(struct ib_cq *cq, void *private) · 54 unmodified lines | ||
| 78 | 112 | static int ib_poll_handler(struct irq_poll *iop, int budget) |
| 79 | 113 | { |
| 80 | 114 | struct ib_cq *cq = container_of(iop, struct ib_cq, iop); |
| 115 | + struct dim *dim = cq->dim; | |
| 81 | 116 | int completed; |
| 82 | 117 | |
| 83 | 118 | 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) · 3 unmodified lines | ||
| 87 | 122 | irq_poll_sched(&cq->iop); |
| 88 | 123 | } |
| 89 | 124 | |
| 125 | + if (dim) | |
| 126 | + rdma_dim(dim, completed); | |
| 127 | + | |
| 90 | 128 | return completed; |
| 91 | 129 | } |
| 92 | 130 | |
| @@ -105,6 +143,8 @@ static void ib_cq_poll_work(struct work_struct *work) · 12 unmodified lines | ||
| 105 | 143 | if (completed >= IB_POLL_BUDGET_WORKQUEUE || |
| 106 | 144 | ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0) |
| 107 | 145 | queue_work(cq->comp_wq, &cq->work); |
| 146 | + else if (cq->dim) | |
| 147 | + rdma_dim(cq->dim, completed); | |
| 108 | 148 | } |
| 109 | 149 | |
| 110 | 150 | 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, · 50 unmodified lines | ||
| 161 | 201 | |
| 162 | 202 | rdma_restrack_kadd(&cq->res); |
| 163 | 203 | |
| 204 | + rdma_dim_init(cq); | |
| 205 | + | |
| 164 | 206 | switch (cq->poll_ctx) { |
| 165 | 207 | case IB_POLL_DIRECT: |
| 166 | 208 | cq->comp_handler = ib_cq_completion_direct; |
| @@ -223,6 +265,9 @@ void ib_free_cq_user(struct ib_cq *cq, struct ib_udata *udata) · 56 unmodified lines | ||
| 223 | 265 | |
| 224 | 266 | rdma_restrack_del(&cq->res); |
| 225 | 267 | cq->device->ops.destroy_cq(cq, udata); |
| 268 | + if (cq->dim) | |
| 269 | + cancel_work_sync(&cq->dim->work); | |
| 270 | + kfree(cq->dim); | |
| 226 | 271 | kfree(cq->wc); |
| 227 | 272 | kfree(cq); |
| 228 | 273 | } |
| @@ -61,6 +61,7 @@ · 60 unmodified lines | ||
| 61 | 61 | #include <linux/cgroup_rdma.h> |
| 62 | 62 | #include <linux/irqflags.h> |
| 63 | 63 | #include <linux/preempt.h> |
| 64 | +#include <linux/dim.h> | |
| 64 | 65 | #include <uapi/rdma/ib_user_verbs.h> |
| 65 | 66 | #include <rdma/rdma_counter.h> |
| 66 | 67 | #include <rdma/restrack.h> |
| @@ -1509,6 +1510,7 @@ struct ib_cq { · 1442 unmodified lines | ||
| 1509 | 1510 | struct work_struct work; |
| 1510 | 1511 | }; |
| 1511 | 1512 | struct workqueue_struct *comp_wq; |
| 1513 | + struct dim *dim; | |
| 1512 | 1514 | /* |
| 1513 | 1515 | * Implementation details of the RDMA core, don't use in drivers: |
| 1514 | 1516 | */ |
| @@ -2576,6 +2578,8 @@ struct ib_device { · 1061 unmodified lines | ||
| 2576 | 2578 | u16 is_switch:1; |
| 2577 | 2579 | /* Indicates kernel verbs support, should not be used in drivers */ |
| 2578 | 2580 | u16 kverbs_provider:1; |
| 2581 | + /* CQ adaptive moderation (RDMA DIM) */ | |
| 2582 | + u16 use_cq_dim:1; | |
| 2579 | 2583 | u8 node_type; |
| 2580 | 2584 | u8 phys_port_cnt; |
| 2581 | 2585 | struct ib_device_attr attrs; |