From fea9a07d9bce8271635691e81b3fb7b3aaae5395 Mon Sep 17 00:00:00 2001
From: Jan Wassenberg <janwas@google.com>
Date: Thu, 3 Jul 2025 08:21:52 -0700
Subject: [PATCH] Avoid affinity related warnings on Apple. Refs #625

PiperOrigin-RevId: 778895832
---
 util/threading.cc | 9 ++++++---
 util/topology.cc  | 7 +++++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/util/threading.cc b/util/threading.cc
index e199b13..6930612 100644
--- a/util/threading.cc
+++ b/util/threading.cc
@@ -77,9 +77,12 @@ class Pinning {
 
       if (HWY_LIKELY(want_pin_)) {
         if (HWY_UNLIKELY(!hwy::PinThreadToLogicalProcessor(lps[task]))) {
-          fprintf(
-              stderr, "Pinning failed for task %d of %zu to %zu (size %zu)\n",
-              static_cast<int>(task), pool.NumWorkers(), lps[task], lps.size());
+          // Apple does not support pinning, hence do not warn there.
+          if (!HWY_OS_APPLE) {
+            HWY_WARN("Pinning failed for task %d of %zu to %zu (size %zu)\n",
+                     static_cast<int>(task), pool.NumWorkers(), lps[task],
+                     lps.size());
+          }
           (void)any_error_.test_and_set();
         }
       }
diff --git a/util/topology.cc b/util/topology.cc
index 46b84d5..0d32f22 100644
--- a/util/topology.cc
+++ b/util/topology.cc
@@ -59,8 +59,11 @@ static LPS EnabledLPs(const BoundedSlice& lp_slice) {
     });
   } else {
     const size_t num_lps = hwy::TotalLogicalProcessors();
-    HWY_WARN("unknown OS affinity, max %zu LPs and slice %zu.", num_lps,
-             lp_slice.Num(num_lps));
+    // Do not warn on Apple, where affinity is not supported.
+    if (!HWY_OS_APPLE) {
+      HWY_WARN("unknown OS affinity, max %zu LPs and slice %zu.", num_lps,
+               lp_slice.Num(num_lps));
+    }
     for (size_t lp = 0; lp < num_lps; ++lp) {
       if (lp_slice.Contains(num_lps, lp)) {
         enabled_lps.Set(lp);