From 7dfc5e922d7c69fd5efdc1ecbbcd6af1245f5462 Mon Sep 17 00:00:00 2001
From: Daniel Verkamp <daniel.verkamp@intel.com>
Date: Tue, 26 Jul 2016 13:03:14 -0700
Subject: [PATCH] nvmf: only poll admin queue once every 10 ms

This should enhance performance, since the hardware admin queue poll
function takes a mutex and should not be in the performance path.

Change-Id: I7e4acde0337aaf7079811612cba5348acf0a467d
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
---
 lib/nvmf/direct.c    | 12 +++++++++---
 lib/nvmf/subsystem.c | 22 +++++++++++++++++++++-
 lib/nvmf/subsystem.h | 10 ++++++++--
 3 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/lib/nvmf/direct.c b/lib/nvmf/direct.c
index 46e5f67eb..53fe5b54d 100644
--- a/lib/nvmf/direct.c
+++ b/lib/nvmf/direct.c
@@ -49,10 +49,15 @@ nvmf_direct_ctrlr_get_data(struct nvmf_session *session)
 }
 
 static void
-nvmf_direct_ctrlr_poll_for_completions(struct nvmf_session *session)
+nvmf_direct_ctrlr_poll_for_io_completions(struct nvmf_session *session)
+{
+	spdk_nvme_qpair_process_completions(session->subsys->ctrlr.dev.direct.io_qpair, 0);
+}
+
+static void
+nvmf_direct_ctrlr_poll_for_admin_completions(struct nvmf_session *session)
 {
 	spdk_nvme_ctrlr_process_admin_completions(session->subsys->ctrlr.dev.direct.ctrlr);
-	spdk_nvme_qpair_process_completions(session->subsys->ctrlr.dev.direct.io_qpair, 0);
 }
 
 static void
@@ -251,5 +256,6 @@ const struct spdk_nvmf_ctrlr_ops spdk_nvmf_direct_ctrlr_ops = {
 	.ctrlr_get_data			= nvmf_direct_ctrlr_get_data,
 	.process_admin_cmd		= nvmf_direct_ctrlr_process_admin_cmd,
 	.process_io_cmd			= nvmf_direct_ctrlr_process_io_cmd,
-	.poll_for_completions		= nvmf_direct_ctrlr_poll_for_completions,
+	.poll_for_io_completions	= nvmf_direct_ctrlr_poll_for_io_completions,
+	.poll_for_admin_completions	= nvmf_direct_ctrlr_poll_for_admin_completions,
 };
diff --git a/lib/nvmf/subsystem.c b/lib/nvmf/subsystem.c
index 486d66625..3c8e1a8ea 100644
--- a/lib/nvmf/subsystem.c
+++ b/lib/nvmf/subsystem.c
@@ -42,6 +42,8 @@
 #include "spdk/trace.h"
 #include "spdk/nvmf_spec.h"
 
+#define ADMIN_POLL_MICROSECONDS 10000 /* 10 milliseconds */
+
 static TAILQ_HEAD(, spdk_nvmf_subsystem) g_subsystems = TAILQ_HEAD_INITIALIZER(g_subsystems);
 
 struct spdk_nvmf_subsystem *
@@ -85,13 +87,29 @@ spdk_nvmf_subsystem_poller(void *arg)
 
 	/* For NVMe subsystems, check the backing physical device for completions. */
 	if (subsystem->subtype == SPDK_NVMF_SUBTYPE_NVME) {
-		session->subsys->ctrlr.ops->poll_for_completions(session);
+		session->subsys->ctrlr.ops->poll_for_io_completions(session);
 	}
 
 	/* For each connection in the session, check for RDMA completions */
 	spdk_nvmf_session_poll(session);
 }
 
+static void
+spdk_nvmf_subsystem_admin_poll(void *arg)
+{
+	struct spdk_nvmf_subsystem *subsystem = arg;
+	struct nvmf_session *session = subsystem->session;
+
+	if (!session) {
+		/* No active connections, so just return */
+		return;
+	}
+
+	if (subsystem->subtype == SPDK_NVMF_SUBTYPE_NVME) {
+		session->subsys->ctrlr.ops->poll_for_admin_completions(session);
+	}
+}
+
 struct spdk_nvmf_subsystem *
 nvmf_create_subsystem(int num, const char *name,
 		      enum spdk_nvmf_subtype subtype,
@@ -114,6 +132,8 @@ nvmf_create_subsystem(int num, const char *name,
 
 	subsystem->lcore = lcore;
 	spdk_poller_register(&subsystem->poller, spdk_nvmf_subsystem_poller, subsystem, lcore, NULL, 0);
+	spdk_poller_register(&subsystem->admin_poller, spdk_nvmf_subsystem_admin_poll, subsystem,
+			     lcore, NULL, ADMIN_POLL_MICROSECONDS);
 
 	TAILQ_INSERT_HEAD(&g_subsystems, subsystem, entries);
 
diff --git a/lib/nvmf/subsystem.h b/lib/nvmf/subsystem.h
index f8e373e3e..b6b9dfe79 100644
--- a/lib/nvmf/subsystem.h
+++ b/lib/nvmf/subsystem.h
@@ -88,9 +88,14 @@ struct spdk_nvmf_ctrlr_ops {
 	int (*process_io_cmd)(struct spdk_nvmf_request *req);
 
 	/**
-	 * Poll for completions.
+	 * Poll for I/O completions.
 	 */
-	void (*poll_for_completions)(struct nvmf_session *session);
+	void (*poll_for_io_completions)(struct nvmf_session *session);
+
+	/**
+	 * Poll for admin completions.
+	 */
+	void (*poll_for_admin_completions)(struct nvmf_session *session);
 };
 
 struct spdk_nvmf_controller {
@@ -127,6 +132,7 @@ struct spdk_nvmf_subsystem {
 	struct spdk_nvmf_controller 	ctrlr;
 
 	struct spdk_poller			*poller;
+	struct spdk_poller			*admin_poller;
 
 	TAILQ_HEAD(, spdk_nvmf_listen_addr)	listen_addrs;
 	uint32_t				num_listen_addrs;