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iw_cxgb4: Support FW write completion WR 

To optimize NVME-oF READ IOPs, use a specialized WQE that combines
the RDMA WRITE and SEND_INV WR chain submitted by the NVME-oF target
driver.

This reduces uP overhead per NVME-oF IO, and results in over 10%
improvement in NVME-oF 4K READ IOPs.

Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Potnuri Bharat Teja 2018-08-02 11:33:04 +05:30 committed by Jason Gunthorpe
parent b9855f4ca0
commit 94245f4ad9
4 changed files with 183 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/infiniband/hw/cxgb4/device.c
View File

@ -866,6 +866,7 @@ static int c4iw_rdev_open(struct c4iw_rdev *rdev)
rdev->status_page->qp_size = rdev->lldi.vr->qp.size;
rdev->status_page->cq_start = rdev->lldi.vr->cq.start;
rdev->status_page->cq_size = rdev->lldi.vr->cq.size;
rdev->status_page->write_cmpl_supported = rdev->lldi.write_cmpl_support;
if (c4iw_wr_log) {
rdev->wr_log = kcalloc(1 << c4iw_wr_log_size_order,

147
drivers/infiniband/hw/cxgb4/qp.c
View File

@ -455,7 +455,12 @@ static int build_isgl(__be64 *queue_start, __be64 *queue_end,
{
int i;
u32 plen = 0;
__be64 *flitp = (__be64 *)isglp->sge;
__be64 *flitp;
if ((__be64 *)isglp == queue_end)
isglp = (struct fw_ri_isgl *)queue_start;
flitp = (__be64 *)isglp->sge;
for (i = 0; i < num_sge; i++) {
if ((plen + sg_list[i].length) < plen)
@ -597,6 +602,56 @@ static int build_rdma_write(struct t4_sq *sq, union t4_wr *wqe,
return 0;
}
static void build_immd_cmpl(struct t4_sq *sq, struct fw_ri_immd_cmpl *immdp,
struct ib_send_wr *wr)
{
memcpy((u8 *)immdp->data, (u8 *)(uintptr_t)wr->sg_list->addr, 16);
memset(immdp->r1, 0, 6);
immdp->op = FW_RI_DATA_IMMD;
immdp->immdlen = 16;
}
static void build_rdma_write_cmpl(struct t4_sq *sq,
struct fw_ri_rdma_write_cmpl_wr *wcwr,
const struct ib_send_wr *wr, u8 *len16)
{
u32 plen;
int size;
/*
* This code assumes the struct fields preceding the write isgl
* fit in one 64B WR slot. This is because the WQE is built
* directly in the dma queue, and wrapping is only handled
* by the code buildling sgls. IE the "fixed part" of the wr
* structs must all fit in 64B. The WQE build code should probably be
* redesigned to avoid this restriction, but for now just add
* the BUILD_BUG_ON() to catch if this WQE struct gets too big.
*/
BUILD_BUG_ON(offsetof(struct fw_ri_rdma_write_cmpl_wr, u) > 64);
wcwr->stag_sink = cpu_to_be32(rdma_wr(wr)->rkey);
wcwr->to_sink = cpu_to_be64(rdma_wr(wr)->remote_addr);
wcwr->stag_inv = cpu_to_be32(wr->next->ex.invalidate_rkey);
wcwr->r2 = 0;
wcwr->r3 = 0;
/* SEND_INV SGL */
if (wr->next->send_flags & IB_SEND_INLINE)
build_immd_cmpl(sq, &wcwr->u_cmpl.immd_src, wr->next);
else
build_isgl((__be64 *)sq->queue, (__be64 *)&sq->queue[sq->size],
&wcwr->u_cmpl.isgl_src, wr->next->sg_list, 1, NULL);
/* WRITE SGL */
build_isgl((__be64 *)sq->queue, (__be64 *)&sq->queue[sq->size],
wcwr->u.isgl_src, wr->sg_list, wr->num_sge, &plen);
size = sizeof(*wcwr) + sizeof(struct fw_ri_isgl) +
wr->num_sge * sizeof(struct fw_ri_sge);
wcwr->plen = cpu_to_be32(plen);
*len16 = DIV_ROUND_UP(size, 16);
}
static int build_rdma_read(union t4_wr *wqe, const struct ib_send_wr *wr,
u8 *len16)
{
@ -627,6 +682,72 @@ static int build_rdma_read(union t4_wr *wqe, const struct ib_send_wr *wr,
return 0;
}
static void post_write_cmpl(struct c4iw_qp *qhp, const struct ib_send_wr *wr)
{
bool send_signaled = (wr->next->send_flags & IB_SEND_SIGNALED) ||
qhp->sq_sig_all;
bool write_signaled = (wr->send_flags & IB_SEND_SIGNALED) ||
qhp->sq_sig_all;
struct t4_swsqe *swsqe;
union t4_wr *wqe;
u16 write_wrid;
u8 len16;
u16 idx;
/*
* The sw_sq entries still look like a WRITE and a SEND and consume
* 2 slots. The FW WR, however, will be a single uber-WR.
*/
wqe = (union t4_wr *)((u8 *)qhp->wq.sq.queue +
qhp->wq.sq.wq_pidx * T4_EQ_ENTRY_SIZE);
build_rdma_write_cmpl(&qhp->wq.sq, &wqe->write_cmpl, wr, &len16);
/* WRITE swsqe */
swsqe = &qhp->wq.sq.sw_sq[qhp->wq.sq.pidx];
swsqe->opcode = FW_RI_RDMA_WRITE;
swsqe->idx = qhp->wq.sq.pidx;
swsqe->complete = 0;
swsqe->signaled = write_signaled;
swsqe->flushed = 0;
swsqe->wr_id = wr->wr_id;
if (c4iw_wr_log) {
swsqe->sge_ts =
cxgb4_read_sge_timestamp(qhp->rhp->rdev.lldi.ports[0]);
swsqe->host_time = ktime_get();
}
write_wrid = qhp->wq.sq.pidx;
/* just bump the sw_sq */
qhp->wq.sq.in_use++;
if (++qhp->wq.sq.pidx == qhp->wq.sq.size)
qhp->wq.sq.pidx = 0;
/* SEND_WITH_INV swsqe */
swsqe = &qhp->wq.sq.sw_sq[qhp->wq.sq.pidx];
swsqe->opcode = FW_RI_SEND_WITH_INV;
swsqe->idx = qhp->wq.sq.pidx;
swsqe->complete = 0;
swsqe->signaled = send_signaled;
swsqe->flushed = 0;
swsqe->wr_id = wr->next->wr_id;
if (c4iw_wr_log) {
swsqe->sge_ts =
cxgb4_read_sge_timestamp(qhp->rhp->rdev.lldi.ports[0]);
swsqe->host_time = ktime_get();
}
wqe->write_cmpl.flags_send = send_signaled ? FW_RI_COMPLETION_FLAG : 0;
wqe->write_cmpl.wrid_send = qhp->wq.sq.pidx;
init_wr_hdr(wqe, write_wrid, FW_RI_RDMA_WRITE_CMPL_WR,
write_signaled ? FW_RI_COMPLETION_FLAG : 0, len16);
t4_sq_produce(&qhp->wq, len16);
idx = DIV_ROUND_UP(len16 * 16, T4_EQ_ENTRY_SIZE);
t4_ring_sq_db(&qhp->wq, idx, wqe);
}
static int build_rdma_recv(struct c4iw_qp *qhp, union t4_recv_wr *wqe,
const struct ib_recv_wr *wr, u8 *len16)
{
@ -1007,6 +1128,30 @@ int c4iw_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
*bad_wr = wr;
return -ENOMEM;
}
/*
* Fastpath for NVMe-oF target WRITE + SEND_WITH_INV wr chain which is
* the response for small NVMEe-oF READ requests. If the chain is
* exactly a WRITE->SEND_WITH_INV and the sgl depths and lengths
* meet the requirements of the fw_ri_write_cmpl_wr work request,
* then build and post the write_cmpl WR. If any of the tests
* below are not true, then we continue on with the tradtional WRITE
* and SEND WRs.
*/
if (qhp->rhp->rdev.lldi.write_cmpl_support &&
CHELSIO_CHIP_VERSION(qhp->rhp->rdev.lldi.adapter_type) >=
CHELSIO_T5 &&
wr && wr->next && !wr->next->next &&
wr->opcode == IB_WR_RDMA_WRITE &&
wr->sg_list[0].length && wr->num_sge <= T4_WRITE_CMPL_MAX_SGL &&
wr->next->opcode == IB_WR_SEND_WITH_INV &&
wr->next->sg_list[0].length == T4_WRITE_CMPL_MAX_CQE &&
wr->next->num_sge == 1 && num_wrs >= 2) {
post_write_cmpl(qhp, wr);
spin_unlock_irqrestore(&qhp->lock, flag);
return 0;
}
while (wr) {
if (num_wrs == 0) {
err = -ENOMEM;

6
drivers/infiniband/hw/cxgb4/t4.h
View File

@ -91,6 +91,9 @@ static inline int t4_max_fr_depth(int use_dsgl)
#define T4_RQ_NUM_BYTES (T4_EQ_ENTRY_SIZE * T4_RQ_NUM_SLOTS)
#define T4_MAX_RECV_SGE 4
#define T4_WRITE_CMPL_MAX_SGL 4
#define T4_WRITE_CMPL_MAX_CQE 16
union t4_wr {
struct fw_ri_res_wr res;
struct fw_ri_wr ri;
@ -101,6 +104,7 @@ union t4_wr {
struct fw_ri_fr_nsmr_wr fr;
struct fw_ri_fr_nsmr_tpte_wr fr_tpte;
struct fw_ri_inv_lstag_wr inv;
struct fw_ri_rdma_write_cmpl_wr write_cmpl;
struct t4_status_page status;
__be64 flits[T4_EQ_ENTRY_SIZE / sizeof(__be64) * T4_SQ_NUM_SLOTS];
};
@ -851,7 +855,7 @@ static inline void t4_set_cq_in_error(struct t4_cq *cq)
struct t4_dev_status_page {
u8 db_off;
u8 pad1;
u8 write_cmpl_supported;
u16 pad2;
u32 pad3;
u64 qp_start;

31
drivers/infiniband/hw/cxgb4/t4fw_ri_api.h
View File

@ -595,6 +595,37 @@ struct fw_ri_send_wr {
#define FW_RI_SEND_WR_SENDOP_G(x) \
(((x) >> FW_RI_SEND_WR_SENDOP_S) & FW_RI_SEND_WR_SENDOP_M)
struct fw_ri_rdma_write_cmpl_wr {
__u8 opcode;
__u8 flags;
__u16 wrid;
__u8 r1[3];
__u8 len16;
__u8 r2;
__u8 flags_send;
__u16 wrid_send;
__be32 stag_inv;
__be32 plen;
__be32 stag_sink;
__be64 to_sink;
union fw_ri_cmpl {
struct fw_ri_immd_cmpl {
__u8 op;
__u8 r1[6];
__u8 immdlen;
__u8 data[16];
} immd_src;
struct fw_ri_isgl isgl_src;
} u_cmpl;
__be64 r3;
#ifndef C99_NOT_SUPPORTED
union fw_ri_write {
struct fw_ri_immd immd_src[0];
struct fw_ri_isgl isgl_src[0];
} u;
#endif
};
struct fw_ri_rdma_read_wr {
__u8 opcode;
__u8 flags;