From 32120b63366a02c6d9d1dab5156fd5cc57aa1b91 Mon Sep 17 00:00:00 2001
From: Jim Harris <james.r.harris@intel.com>
Date: Tue, 23 May 2017 14:40:53 -0700
Subject: [PATCH] examples/nvme/perf: fix latency calculations

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: I0c47f2086d4f895cd75f32efc7df30d7182adcb1

Reviewed-on: https://review.gerrithub.io/362269
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
---
 examples/nvme/perf/perf.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/examples/nvme/perf/perf.c b/examples/nvme/perf/perf.c
index 8b863af45..896c54f3f 100644
--- a/examples/nvme/perf/perf.c
+++ b/examples/nvme/perf/perf.c
@@ -111,9 +111,10 @@ struct ns_entry {
  * store the bucket data.
  */
 #define BUCKET_SHIFT 7
+#define BUCKET_LSB (64 - BUCKET_SHIFT)
 #define NUM_BUCKETS_PER_RANGE (1ULL << BUCKET_SHIFT)
 #define BUCKET_MASK (NUM_BUCKETS_PER_RANGE - 1)
-#define NUM_BUCKET_RANGES (64 - BUCKET_SHIFT + 1)
+#define NUM_BUCKET_RANGES (BUCKET_LSB + 1)
 
 struct ns_worker_ctx {
 	struct ns_entry		*entry;
@@ -206,8 +207,8 @@ get_bucket_range(uint64_t tsc)
 
 	clz = __builtin_clzll(tsc);
 
-	if (clz <= NUM_BUCKET_RANGES) {
-		range = NUM_BUCKET_RANGES - clz;
+	if (clz <= BUCKET_LSB) {
+		range = BUCKET_LSB - clz;
 	} else {
 		range = 0;
 	}