From eae579be0d8980b48c43856711cbb11e56011b6f Mon Sep 17 00:00:00 2001
From: Peter Lawrey <peter.lawrey@chronicle.software>
Date: Mon, 5 Sep 2022 11:31:45 +0100
Subject: [PATCH] Delay producing a warning until a lock is actually used

---
 .../main/java/net/openhft/affinity/AffinityLock.java  | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/affinity/src/main/java/net/openhft/affinity/AffinityLock.java b/affinity/src/main/java/net/openhft/affinity/AffinityLock.java
index fc2eae07c..67642daf5 100644
--- a/affinity/src/main/java/net/openhft/affinity/AffinityLock.java
+++ b/affinity/src/main/java/net/openhft/affinity/AffinityLock.java
@@ -121,7 +121,6 @@ private static BitSet getReservedAffinity0() {
             reserverable.set(1, PROCESSORS, true);
             reserverable.andNot(BASE_AFFINITY);
             if (reserverable.isEmpty() && PROCESSORS > 1) {
-                LoggerFactory.getLogger(AffinityLock.class).info("No isolated CPUs found, so assuming CPUs 1 to {} available.", (PROCESSORS - 1));
                 // make all but first CPUs available
                 reserverable.set(1, PROCESSORS);
                 return reserverable;
@@ -149,6 +148,14 @@ public static AffinityLock acquireLock() {
         return acquireLock(true);
     }
 
+    static class Warnings {
+        static void warmNoReservedCPUs() {
+            if (RESERVED_AFFINITY.isEmpty() && PROCESSORS > 1) {
+                LoggerFactory.getLogger(AffinityLock.class).info("No isolated CPUs found, so assuming CPUs 1 to {} available.", (PROCESSORS - 1));
+            }
+        }
+    }
+
     /**
      * Assign any free core to this thread. <p> In reality, only one cpu is assigned, the rest of
      * the threads for that core are reservable so they are not used.
@@ -294,6 +301,7 @@ public static AffinityLock acquireCore(boolean bind) {
     }
 
     private static AffinityLock acquireLock(boolean bind, int cpuId, @NotNull AffinityStrategy... strategies) {
+        Warnings.warmNoReservedCPUs();
         return LOCK_INVENTORY.acquireLock(bind, cpuId, strategies);
     }
 
@@ -310,6 +318,7 @@ private static AffinityLock tryAcquireLock(boolean bind, int cpuId) {
     }
 
     private static AffinityLock acquireCore(boolean bind, int cpuId, @NotNull AffinityStrategy... strategies) {
+        Warnings.warmNoReservedCPUs();
         return LOCK_INVENTORY.acquireCore(bind, cpuId, strategies);
     }