From 24d508744103b82707a10b067cea87ab08f66032 Mon Sep 17 00:00:00 2001
From: Ben Walker <benjamin.walker@intel.com>
Date: Tue, 26 Dec 2017 11:40:00 -0700
Subject: [PATCH] perf: Add option to create unused io queue pairs

For some testing, we need queue pairs to exist but not actually
be in use.

Change-Id: I2b17ff0172c9ec002692babcf7d4d612c3062eb4
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/392977
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
---
 examples/nvme/perf/perf.c | 41 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/examples/nvme/perf/perf.c b/examples/nvme/perf/perf.c
index 5e6344e10d..c930ce3953 100644
--- a/examples/nvme/perf/perf.c
+++ b/examples/nvme/perf/perf.c
@@ -51,6 +51,9 @@
 struct ctrlr_entry {
 	struct spdk_nvme_ctrlr			*ctrlr;
 	struct spdk_nvme_intel_rw_latency_page	*latency_page;
+
+	struct spdk_nvme_qpair			**unused_qpairs;
+
 	struct ctrlr_entry			*next;
 	char					name[1024];
 };
@@ -177,6 +180,7 @@ static int g_rw_percentage;
 static int g_is_random;
 static int g_queue_depth;
 static int g_nr_io_queues_per_ns = 1;
+static int g_nr_unused_io_queues = 0;
 static int g_time_in_sec;
 static uint32_t g_max_completions;
 static int g_dpdk_mem;
@@ -362,6 +366,26 @@ register_ctrlr(struct spdk_nvme_ctrlr *ctrlr)
 		register_ns(ctrlr, ns);
 	}
 
+	if (g_nr_unused_io_queues) {
+		int i;
+
+		printf("Creating %u unused qpairs for controller %s\n", g_nr_unused_io_queues, entry->name);
+
+		entry->unused_qpairs = calloc(g_nr_unused_io_queues, sizeof(struct spdk_nvme_qpair *));
+		if (!entry->unused_qpairs) {
+			fprintf(stderr, "Unable to allocate memory for qpair array\n");
+			exit(1);
+		}
+
+		for (i = 0; i < g_nr_unused_io_queues; i++) {
+			entry->unused_qpairs[i] = spdk_nvme_ctrlr_alloc_io_qpair(ctrlr, NULL, 0);
+			if (!entry->unused_qpairs[i]) {
+				fprintf(stderr, "Unable to allocate unused qpair. Did you request too many?\n");
+				exit(1);
+			}
+		}
+	}
+
 }
 
 #if HAVE_LIBAIO
@@ -936,6 +960,7 @@ static void usage(char *program_name)
 	printf("\t[-q io depth]\n");
 	printf("\t[-s io size in bytes]\n");
 	printf("\t[-n number of io queues per namespace. default: 1]\n");
+	printf("\t[-U number of unused io queues per controller. default: 0]\n");
 	printf("\t[-w io pattern type, must be one of\n");
 	printf("\t\t(read, write, randread, randwrite, rw, randrw)]\n");
 	printf("\t[-M rwmixread (100 for reads, 0 for writes)]\n");
@@ -1275,7 +1300,7 @@ parse_args(int argc, char **argv)
 	g_core_mask = NULL;
 	g_max_completions = 0;
 
-	while ((op = getopt(argc, argv, "c:d:e:i:lm:n:q:r:s:t:w:DLM:")) != -1) {
+	while ((op = getopt(argc, argv, "c:d:e:i:lm:n:q:r:s:t:w:DLM:U:")) != -1) {
 		switch (op) {
 		case 'c':
 			g_core_mask = optarg;
@@ -1329,6 +1354,9 @@ parse_args(int argc, char **argv)
 			g_rw_percentage = atoi(optarg);
 			mix_specified = true;
 			break;
+		case 'U':
+			g_nr_unused_io_queues = atoi(optarg);
+			break;
 		default:
 			usage(argv[0]);
 			return 1;
@@ -1564,6 +1592,17 @@ unregister_controllers(void)
 		    spdk_nvme_ctrlr_is_feature_supported(entry->ctrlr, SPDK_NVME_INTEL_FEAT_LATENCY_TRACKING)) {
 			set_latency_tracking_feature(entry->ctrlr, false);
 		}
+
+		if (g_nr_unused_io_queues) {
+			int i;
+
+			for (i = 0; i < g_nr_unused_io_queues; i++) {
+				spdk_nvme_ctrlr_free_io_qpair(entry->unused_qpairs[i]);
+			}
+
+			free(entry->unused_qpairs);
+		}
+
 		spdk_nvme_detach(entry->ctrlr);
 		free(entry);
 		entry = next;