address reviewer's comment

onnxruntime/test/perftest/command_args_parser.cc

@@ -196,15 +196,18 @@ bool CommandLineParser::ParseArguments(PerformanceTestConfig& test_config, int a
   absl::SetFlagsUsageConfig(config);
   absl::SetProgramUsageMessage(CustomUsageMessage());
 
-  auto utf8_strings = utils::ConvertArgvToUtf8Strings(argc, argv);
-  auto utf8_argv = utils::CStringsFromStrings(utf8_strings);
+  auto utf8_argv_strings = utils::ConvertArgvToUtf8Strings(argc, argv);
+  auto utf8_argv = utils::CStringsFromStrings(utf8_argv_strings);
   auto positional = absl::ParseCommandLine(static_cast<int>(utf8_argv.size()), utf8_argv.data());
 
   // -f
   {
     const auto& dim_override_str = absl::GetFlag(FLAGS_f);
     if (!dim_override_str.empty()) {
-      if (!ParseDimensionOverride(dim_override_str, test_config.run_config.free_dim_name_overrides)) {
+      // Abseil doesn't support the same option being provided multiple times — only the last occurrence is applied.
+      // To preserve the intended usage of '-f', where users may specify it multiple times to override different dimension names,
+      // we need to manually parse argv.
+      if (!ParseDimensionOverrideFromArgv(argc, utf8_argv_strings, "f", test_config.run_config.free_dim_name_overrides)) {
         return false;
       }
     }
@@ -214,7 +217,8 @@ bool CommandLineParser::ParseArguments(PerformanceTestConfig& test_config, int a
   {
     const auto& dim_override_str = absl::GetFlag(FLAGS_F);
     if (!dim_override_str.empty()) {
-      if (!ParseDimensionOverride(dim_override_str, test_config.run_config.free_dim_denotation_overrides)) {
+      // Same reason as '-f' above to manully parse argv.
+      if (!ParseDimensionOverrideFromArgv(argc, utf8_argv_strings, "F", test_config.run_config.free_dim_denotation_overrides)) {
         return false;
       }
     }

onnxruntime/test/perftest/main.cc

@@ -35,7 +35,7 @@ int real_main(int argc, char* argv[]) {
     }
     ORT_CATCH(const Ort::Exception& e) {
       ORT_HANDLE_EXCEPTION([&]() {
-        fprintf(stderr, "Error creating environment: %s \n", e.what());
+        std::cerr << "Error creating environment: " << e.what() << std::endl;
         failed = true;
       });
     }
@@ -98,7 +98,7 @@ int main(int argc, char* argv[]) {
   }
   ORT_CATCH(const std::exception& ex) {
     ORT_HANDLE_EXCEPTION([&]() {
-      fprintf(stderr, "%s\n", ex.what());
+      std::cerr << ex.what() << std::endl;
       retval = -1;
     });
   }

onnxruntime/test/perftest/strings_helper.cc

@@ -77,7 +77,7 @@ bool ParseDimensionOverride(const std::string& input, std::map<std::string, int6
       }
       ORT_CATCH(const std::exception& ex) {
         ORT_HANDLE_EXCEPTION([&]() {
-          fprintf(stderr, "Error parsing free dimension override value: %s, %s\n", override_val_str.c_str(), ex.what());
+          std::cerr << "Error parsing free dimension override value: " << override_val_str.c_str() << ", " << ex.what() << std::endl;
         });
         return false;
       }
@@ -87,6 +87,22 @@ bool ParseDimensionOverride(const std::string& input, std::map<std::string, int6
   return true;
 }
 
+bool ParseDimensionOverrideFromArgv(int argc, std::vector<std::string> argv, std::string option, std::map<std::string, int64_t>& free_dim_override_map) {
+  for (int i = 1; i < argc; ++i) {
+    auto utf8_arg = argv[i];
+    if (utf8_arg == ("-" + option) || utf8_arg == ("--" + option)) {
+      auto value_idx = i + 1;
+      if (value_idx >= argc || argv[value_idx][0] == '-') {
+        std::cerr << utf8_arg << " should be followed by a key-value pair." << std::endl;
+        return false;
+      }
+
+      if (!ParseDimensionOverride(argv[value_idx], free_dim_override_map)) return false;
+    }
+  }
+  return true;
+}
+
 void ParseEpOptions(const std::string& input, std::vector<std::unordered_map<std::string, std::string>>& result) {
   auto tokens = utils::SplitString(input, ";", true);
 

onnxruntime/test/perftest/strings_helper.h

@@ -17,6 +17,8 @@ void ParseSessionConfigs(const std::string& configs_string,
 
 bool ParseDimensionOverride(const std::string& input, std::map<std::string, int64_t>& free_dim_override_map);
 
+bool ParseDimensionOverrideFromArgv(int argc, std::vector<std::string> argv, std::string option, std::map<std::string, int64_t>& free_dim_override_map);
+
 void ParseEpList(const std::string& input, std::vector<std::string>& result);
 
 void ParseEpOptions(const std::string& input, std::vector<std::unordered_map<std::string, std::string>>& result);