prov/verbs: Add support for IBV_ACCESS_RELAXED_ORDERING

IBV_ACCESS_RELAXED_ORDERING allows the system to reorder
Send/Write/Atomic operations to improve performance.

The patch enables IBV_ACCESS_RELAXED_ORDERING if the application
has requested no ordering in TX/RX attributes.

Signed-off-by: Sylvain Didelot <[email protected]>

prov/verbs/configure.m4

@@ -93,6 +93,16 @@ AC_DEFUN([FI_VERBS_CONFIGURE],[
 	AC_DEFINE_UNQUOTED([VERBS_HAVE_DMABUF_MR],[$VERBS_HAVE_DMABUF_MR],
 		[Whether infiniband/verbs.h has ibv_reg_dmabuf_mr() support or not])
 
+	#See if we have rdma-core IBV_ACCESS_RELAXED_ORDERING mr support
+	VERBS_HAVE_RELAXED_ORDERING_MR=0
+	AS_IF([test $verbs_ibverbs_happy -eq 1],[
+		AC_CHECK_DECL([IBV_ACCESS_RELAXED_ORDERING],
+			[VERBS_HAVE_RELAXED_ORDERING_MR=1],[],
+			[#include <infiniband/verbs.h>])
+		])
+	AC_DEFINE_UNQUOTED([VERBS_HAVE_RELAXED_ORDERING_MR],[$VERBS_HAVE_RELAXED_ORDERING_MR],
+		[Whether infiniband/verbs.h has IBV_ACCESS_RELAXED_ORDERING support or not])
+
 	CPPFLAGS=$fi_verbs_configure_save_CPPFLAGS
 
 	# Technically, verbs_ibverbs_CPPFLAGS and

prov/verbs/src/verbs_domain.c

@@ -246,9 +246,12 @@ static int vrb_open_device_by_name(struct vrb_domain *domain, const char *name)
 		const char *rdma_name = ibv_get_device_name(dev_list[i]->device);
 		switch (domain->ep_type) {
 		case FI_EP_MSG:
-			ret = domain->ext_flags & VRB_USE_XRC ?
-				vrb_cmp_xrc_domain_name(name, rdma_name) :
-				strcmp(name, rdma_name);
+			if (domain->ext_flags & VRB_USE_XRC)
+				ret = vrb_cmp_xrc_domain_name(name, rdma_name);
+			else if (domain->ext_flags & VRB_USE_RO)
+				ret = vrb_cmp_ro_domain_name(name, rdma_name);
+			else
+				ret = strcmp(name, rdma_name);
 			break;
 		case FI_EP_DGRAM:
 			ret = strncmp(name, rdma_name,
@@ -345,6 +348,9 @@ vrb_domain(struct fid_fabric *fabric, struct fi_info *info,
 	if (!_domain->info)
 		goto err2;
 
+	if (VRB_RO_ENABLED(info))
+		_domain->ext_flags |= VRB_USE_RO;
+
 	_domain->ep_type = VRB_EP_TYPE(info);
 	_domain->ext_flags |= vrb_is_xrc_info(info) ? VRB_USE_XRC : 0;
 

prov/verbs/src/verbs_eq.c

@@ -169,6 +169,9 @@ vrb_pep_dev_domain_match(struct fi_info *hints, const char *devname)
 	if ((VRB_EP_PROTO(hints)) == FI_PROTO_RDMA_CM_IB_XRC)
 		ret = vrb_cmp_xrc_domain_name(hints->domain_attr->name,
 						 devname);
+	else if (VRB_RO_ENABLED(hints))
+		ret = vrb_cmp_ro_domain_name(hints->domain_attr->name,
+					     devname);
 	else
 		ret = strcmp(hints->domain_attr->name, devname);
 

prov/verbs/src/verbs_info.c

@@ -113,6 +113,15 @@ const struct fi_rx_attr verbs_rx_attr = {
 	.total_buffered_recv	= 0,
 };
 
+const struct fi_rx_attr verbs_ro_rx_attr = {
+	.caps			= VERBS_MSG_RX_CAPS,
+	.mode			= VERBS_RX_MODE,
+	.op_flags		= FI_COMPLETION,
+	.msg_order		= 0,
+	.comp_order		= FI_ORDER_STRICT | FI_ORDER_DATA,
+	.total_buffered_recv	= 0,
+};
+
 const struct fi_rx_attr verbs_dgram_rx_attr = {
 	.caps			= VERBS_DGRAM_RX_CAPS,
 	.mode			= VERBS_DGRAM_RX_MODE | VERBS_RX_MODE,
@@ -132,6 +141,16 @@ const struct fi_tx_attr verbs_tx_attr = {
 	.rma_iov_limit		= 1,
 };
 
+const struct fi_tx_attr verbs_ro_tx_attr = {
+	.caps			= VERBS_MSG_TX_CAPS,
+	.mode			= 0,
+	.op_flags		= VERBS_TX_OP_FLAGS,
+	.msg_order		= 0,
+	.comp_order		= FI_ORDER_STRICT,
+	.inject_size		= 0,
+	.rma_iov_limit		= 1,
+};
+
 const struct fi_tx_attr verbs_dgram_tx_attr = {
 	.caps			= VERBS_DGRAM_TX_CAPS,
 	.mode			= 0,
@@ -146,18 +165,28 @@ const struct verbs_ep_domain verbs_msg_domain = {
 	.suffix			= "",
 	.type			= FI_EP_MSG,
 	.protocol		= FI_PROTO_UNSPEC,
+	.relaxed_ordering	= false,
+};
+
+const struct verbs_ep_domain verbs_msg_ro_domain = {
+	.suffix			= "-ro",
+	.type			= FI_EP_MSG,
+	.protocol		= FI_PROTO_UNSPEC,
+	.relaxed_ordering	= true,
 };
 
 const struct verbs_ep_domain verbs_msg_xrc_domain = {
 	.suffix			= "-xrc",
 	.type			= FI_EP_MSG,
 	.protocol		= FI_PROTO_RDMA_CM_IB_XRC,
+	.relaxed_ordering	= false,
 };
 
 const struct verbs_ep_domain verbs_dgram_domain = {
 	.suffix			= "-dgram",
 	.type			= FI_EP_DGRAM,
 	.protocol		= FI_PROTO_UNSPEC,
+	.relaxed_ordering	= false,
 };
 
 /* The list (not thread safe) is populated once when the provider is initialized */
@@ -770,8 +799,13 @@ static int vrb_alloc_info(struct ibv_context *ctx, struct fi_info **info,
 	switch (ep_dom->type) {
 	case FI_EP_MSG:
 		fi->caps = VERBS_MSG_CAPS;
-		*(fi->tx_attr) = verbs_tx_attr;
-		*(fi->rx_attr) = verbs_rx_attr;
+		if (ep_dom->relaxed_ordering) {
+			*(fi->tx_attr) = verbs_ro_tx_attr;
+			*(fi->rx_attr) = verbs_ro_rx_attr;
+		} else {
+			*(fi->tx_attr) = verbs_tx_attr;
+			*(fi->rx_attr) = verbs_rx_attr;
+		}
 		fi->addr_format = FI_SOCKADDR_IB;
 		break;
 	case FI_EP_DGRAM:
@@ -1332,7 +1366,7 @@ static int vrb_device_has_ipoib_addr(const char *dev_name)
 	return 0;
 }
 
-#define VERBS_NUM_DOMAIN_TYPES		3
+#define VERBS_NUM_DOMAIN_TYPES		4
 
 static int vrb_init_info(const struct fi_info **all_infos)
 {
@@ -1379,12 +1413,14 @@ static int vrb_init_info(const struct fi_info **all_infos)
 	if (!vrb_gl_data.iface)
 		vrb_get_sib(&verbs_devs);
 
-	if (dlist_empty(&verbs_devs))
+	if (dlist_empty(&verbs_devs)) {
 		FI_WARN(&vrb_prov, FI_LOG_FABRIC,
 			"no valid IPoIB interfaces found, FI_EP_MSG endpoint "
 			"type would not be available\n");
-	else
+	} else {
 		ep_type[dom_count++] = &verbs_msg_domain;
+		ep_type[dom_count++] = &verbs_msg_ro_domain;
+	}
 
 	if (!vrb_gl_data.msg.prefer_xrc && VERBS_HAVE_XRC)
 		ep_type[dom_count++] = &verbs_msg_xrc_domain;
@@ -1562,6 +1598,10 @@ int vrb_get_matching_info(uint32_t version, const struct fi_info *hints,
 				       "XRC FI_EP_MSG endpoints\n");
 				continue;
 			}
+
+			if (VRB_RO_ENABLED(hints) && (check_info->tx_attr->msg_order ||
+			    check_info->rx_attr->msg_order))
+				continue;
 		}
 
 		if ((check_info->ep_attr->type == FI_EP_MSG) && passive) {

prov/verbs/src/verbs_mr.c

@@ -201,6 +201,9 @@ vrb_mr_ofi2ibv_access(uint64_t ofi_access, struct vrb_domain *domain)
 			      IBV_ACCESS_REMOTE_WRITE |
 			      IBV_ACCESS_REMOTE_ATOMIC;
 
+	if (domain->ext_flags & VRB_USE_RO)
+		ibv_access |= VRB_ACCESS_RELAXED_ORDERING;
+
 	return ibv_access;
 }
 

prov/verbs/src/verbs_ofi.h

@@ -138,6 +138,9 @@
 #define VRB_EP_PROTO(info)						\
 	(((info) && (info)->ep_attr) ? (info)->ep_attr->protocol :	\
 					FI_PROTO_UNSPEC)
+#define VRB_RO_ENABLED(info)    \
+	((info)->tx_attr && !(info)->tx_attr->msg_order &&		\
+	 (info)->rx_attr && !(info)->rx_attr->msg_order)
 
 #define VRB_MEM_ALIGNMENT (64)
 #define VRB_BUF_ALIGNMENT (4096) /* TODO: Page or MTU size */
@@ -366,6 +369,7 @@ struct fi_ops_cm *vrb_pep_ops_cm(struct vrb_pep *pep);
 enum {
 	VRB_USE_XRC = BIT(0),
 	VRB_USE_ODP = BIT(1),
+	VRB_USE_RO  = BIT(2),
 };
 
 struct vrb_domain {
@@ -437,6 +441,12 @@ int vrb_cq_open(struct fid_domain *domain, struct fi_cq_attr *attr,
 		   struct fid_cq **cq, void *context);
 int vrb_cq_trywait(struct vrb_cq *cq);
 
+#if VERBS_HAVE_RELAXED_ORDERING_MR
+#define VRB_ACCESS_RELAXED_ORDERING IBV_ACCESS_RELAXED_ORDERING
+#else
+#define VRB_ACCESS_RELAXED_ORDERING 0
+#endif
+
 struct vrb_mem_desc {
 	struct fid_mr		mr_fid;
 	struct ibv_mr		*mr;
@@ -839,10 +849,12 @@ struct verbs_ep_domain {
 	char			*suffix;
 	enum fi_ep_type		type;
 	uint32_t		protocol;
+	bool			relaxed_ordering;
 };
 
 extern const struct verbs_ep_domain verbs_dgram_domain;
 extern const struct verbs_ep_domain verbs_msg_xrc_domain;
+extern const struct verbs_ep_domain verbs_msg_ro_domain;
 
 int vrb_check_ep_attr(const struct fi_info *hints,
 			 const struct fi_info *info);
@@ -860,6 +872,16 @@ static inline int vrb_cmp_xrc_domain_name(const char *domain_name,
 						 domain_len - suffix_len) : -1;
 }
 
+static inline int vrb_cmp_ro_domain_name(const char *domain_name,
+					     const char *rdma_name)
+{
+	size_t domain_len = strlen(domain_name);
+	size_t suffix_len = strlen(verbs_msg_ro_domain.suffix);
+
+	return domain_len > suffix_len ? strncmp(domain_name, rdma_name,
+						 domain_len - suffix_len) : -1;
+}
+
 int vrb_cq_signal(struct fid_cq *cq);
 
 struct vrb_eq_entry *vrb_eq_alloc_entry(uint32_t event,