From e4b8bb208d74af08666d80ff94ddb5fe8c1433e5 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 23 Jun 2023 11:36:26 +0200
Subject: Tune Windows fdselect() implementation

---
 libbutl/fdstream.cxx | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

(limited to 'libbutl')

diff --git a/libbutl/fdstream.cxx b/libbutl/fdstream.cxx
index 18f611f..8098e50 100644
--- a/libbutl/fdstream.cxx
+++ b/libbutl/fdstream.cxx
@@ -34,6 +34,7 @@
 
 #  include <wchar.h> // wcsncmp(), wcsstr()
 
+#  include <thread>    // this_thread::yield()
 #  include <algorithm> // count()
 #endif
 
@@ -2064,7 +2065,9 @@ namespace butl
 
       // Use exponential backoff but not too aggressive and with 25ms max.
       //
-      DWORD t (static_cast<DWORD> (i >= 100 ? 25 : 1 + (i / 4)));
+      DWORD t (
+        static_cast<DWORD> (i <= 1000  ?  0 :
+                            i >= 1000 + 100 ? 25 : 1 + ((i - 1000) / 4)));
 
       if (timeout)
       {
@@ -2081,7 +2084,10 @@ namespace butl
           break;
       }
 
-      Sleep (t);
+      if (t == 0)
+        this_thread::yield ();
+      else
+        Sleep (t);
     }
 
     return make_pair (r, 0);
-- 
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