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 exports FI_VERBS_RELAXED_ORDERING=1. Signed-off-by: Sylvain Didelot <sdidelot@ddn.com>
sydidelot · Dec 18, 2023 · 8db96bd · 8db96bd
1 parent 9d85679
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diff --git a/man/fi_verbs.7.md b/man/fi_verbs.7.md
@@ -203,6 +203,10 @@ The verbs provider checks for the following environment variables.
   testing the functionality of the dmabuf_peer_mem hooking provider and the
   corresponding kernel driver. (default: yes)
 
+*FI_VERBS_RELAXED_ORDERING*
+: If supported, allow the system to reorder Send/Write/Atomic operations
+  to improve performance (default: no)
+
 ### Variables specific to MSG endpoints
 
 *FI_VERBS_IFACE*

diff --git a/prov/verbs/configure.m4 b/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

diff --git a/prov/verbs/src/verbs_init.c b/prov/verbs/src/verbs_init.c
@@ -702,6 +702,12 @@ int vrb_read_params(void)
 	VRB_INFO(FI_LOG_CORE, "dmabuf support is %s\n",
 		 vrb_gl_data.dmabuf_support ? "enabled" : "disabled");
 
+	if (vrb_get_param_bool("relaxed_ordering", "Enable relaxed ordering.",
+			       (int *)&vrb_gl_data.relaxed_ordering)) {
+		VRB_WARN(FI_LOG_CORE, "Invalid value of relaxed_ordering\n");
+		return -FI_EINVAL;
+	}
+
 	/* MSG-specific parameter */
 	if (vrb_get_param_str("iface", "The prefix or the full name of the "
 			      "network interface associated with the verbs "

diff --git a/prov/verbs/src/verbs_mr.c b/prov/verbs/src/verbs_mr.c
@@ -204,6 +204,9 @@ vrb_mr_ofi2ibv_access(uint64_t ofi_access, struct vrb_domain *domain)
 			      IBV_ACCESS_REMOTE_WRITE |
 			      IBV_ACCESS_REMOTE_ATOMIC;
 
+	if (vrb_gl_data.relaxed_ordering)
+		ibv_access |= VRB_ACCESS_RELAXED_ORDERING;
+
 	return ibv_access;
 }
 

diff --git a/prov/verbs/src/verbs_ofi.h b/prov/verbs/src/verbs_ofi.h
@@ -185,6 +185,7 @@ extern struct vrb_gl_data {
 
 	bool	peer_mem_support;
 	bool	dmabuf_support;
+	bool	relaxed_ordering;
 } vrb_gl_data;
 
 struct verbs_addr {
@@ -438,6 +439,12 @@ 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;