From dd005911b955da49a11aa755acb9addc0c8a2a24 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Fri, 29 Apr 2022 12:23:53 -0600
Subject: [PATCH] [benchmark-set] Reduce lookup benchmark overhead

Turnsout 90% was overhead...  Now lookup is in the 4ns ballpark.
---
 perf/benchmark-set.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/perf/benchmark-set.cc b/perf/benchmark-set.cc
index 64bc47039..022b9b003 100644
--- a/perf/benchmark-set.cc
+++ b/perf/benchmark-set.cc
@@ -82,9 +82,10 @@ static void BM_SetLookup(benchmark::State& state) {
   RandomSet(set_size, max_value, original);
   assert(hb_set_get_population(original) == set_size);
 
+  auto needle = max_value / 2;
   for (auto _ : state) {
     benchmark::DoNotOptimize(
-        hb_set_has (original, rand() % max_value));
+        hb_set_has (original, needle));
   }
 
   hb_set_destroy(original);