From e5847d85a6676e87832a188792078d35cde25986 Mon Sep 17 00:00:00 2001
From: Arnaud Giersch <arnaud.giersch@univ-fcomte.fr>
Date: Wed, 1 Mar 2023 11:03:20 +0100
Subject: [PATCH] Lookup only once in map.

---
 src/kernel/actor/SimcallObserver.hpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/kernel/actor/SimcallObserver.hpp b/src/kernel/actor/SimcallObserver.hpp
index 71f7e13e60..1dfc713edc 100644
--- a/src/kernel/actor/SimcallObserver.hpp
+++ b/src/kernel/actor/SimcallObserver.hpp
@@ -147,9 +147,10 @@ public:
 template <typename A> static std::string ptr_to_id(A* ptr)
 {
   static std::unordered_map<A*, std::string> map;
-  if (map.find(ptr) == map.end())
-    map.insert(std::make_pair(ptr, std::to_string(map.size() + 1)));
-  return map[ptr];
+  auto [elm, inserted] = map.try_emplace(ptr);
+  if (inserted)
+    elm->second = std::to_string(map.size());
+  return elm->second;
 }
 
 } // namespace simgrid::kernel::actor
-- 
2.20.1