From ac20f36eae73249cb503ba27e6c2e73a99a51eed Mon Sep 17 00:00:00 2001
From: Alex Peck <alexpeck@microsoft.com>
Date: Sun, 25 Sep 2022 18:01:40 -0700
Subject: [PATCH] warmup

---
 BitFaster.Caching.ThroughputAnalysis/ConfigFactory.cs  | 10 +++++++++-
 .../ThroughputBenchmark.cs                             |  4 ++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/BitFaster.Caching.ThroughputAnalysis/ConfigFactory.cs b/BitFaster.Caching.ThroughputAnalysis/ConfigFactory.cs
index 4feaf93f..76a0897b 100644
--- a/BitFaster.Caching.ThroughputAnalysis/ConfigFactory.cs
+++ b/BitFaster.Caching.ThroughputAnalysis/ConfigFactory.cs
@@ -27,7 +27,7 @@ public static (ThroughputBenchmarkBase, IThroughputBenchConfig, int) Create(Mode
                 case Mode.Update:
                     return (new UpdateThroughputBenchmark(), new ZipfConfig(iterations, samples, s, n), cacheSize);
                 case Mode.Evict:
-                    return (new ReadThroughputBenchmark(), new EvictionConfig(iterations, samples, maxThreads), cacheSize);
+                    return (new ReadThroughputBenchmark() { Initialize = c => EvictionInit(c) }, new EvictionConfig(iterations, samples, maxThreads), cacheSize);
             }
 
             throw new InvalidOperationException();
@@ -50,5 +50,13 @@ public static (ThroughputBenchmarkBase, IThroughputBenchConfig, int) Create(Mode
             < 5_000_000 => cacheSize * 2,
             _ => cacheSize
         };
+
+        private static void EvictionInit(ICache<int, int> cache)
+        {
+            Parallel.ForEach(Enumerable.Range(0, cache.Policy.Eviction.Value.Capacity).Select(i => -i), i =>
+            {
+                cache.GetOrAdd(i, key => i);
+            });
+        }
     }
 }
diff --git a/BitFaster.Caching.ThroughputAnalysis/ThroughputBenchmark.cs b/BitFaster.Caching.ThroughputAnalysis/ThroughputBenchmark.cs
index 99574557..a7b24e8f 100644
--- a/BitFaster.Caching.ThroughputAnalysis/ThroughputBenchmark.cs
+++ b/BitFaster.Caching.ThroughputAnalysis/ThroughputBenchmark.cs
@@ -13,10 +13,14 @@ public interface IThroughputBenchmark
 
     public abstract class ThroughputBenchmarkBase
     {
+        public Action<ICache<int, int>> Initialize { get; set; }
+
         public double Run(int warmup, int runs, int threads, IThroughputBenchConfig config, ICache<int, int> cache)
         {
             double[] results = new double[warmup + runs];
 
+            Initialize?.Invoke(cache);
+
             for (int i = 0; i < warmup + runs; i++)
             {
                 results[i] = Run(threads, config, cache);