Re-integrate and document the fan-out benchmark

tests/benchmarks/CMakeLists.txt

@@ -1,6 +1,6 @@
 find_package(benchmark QUIET)
 
 # add_subdirectory(cluster)
-# add_subdirectory(fan-out)
+add_subdirectory(fan-out)
 # add_subdirectory(routing-table)
 # add_subdirectory(serialization)

tests/benchmarks/fan-out/CMakeLists.txt

@@ -0,0 +1,7 @@
+add_executable(broker-fan-out-benchmark
+  fan-out.cc
+)
+target_link_libraries(broker-fan-out-benchmark PRIVATE ${BROKER_LIBRARY})
+target_include_directories(broker-fan-out-benchmark PRIVATE
+                           "${CMAKE_CURRENT_SOURCE_DIR}"
+                           "${CMAKE_CURRENT_BINARY_DIR}")

tests/benchmarks/fan-out/README.md

@@ -0,0 +1,9 @@
+The `broker-fan-out-benchmark` program is a standalone, self-contained tool to
+measure the performance of a single publisher and multiple subscribers. All
+Broker endpoints are created in a single process.
+
+By default, the program has no output and simply runs until completion. The
+intended use is to run the program with a tool like `time` to measure the time
+it takes to send a certain number of messages to all subscribers.
+
+To see all available options, run the program with the `--help` flag.

tests/benchmarks/fan-out/fan-out.cc

@@ -43,9 +43,9 @@ enum class term_color {
 
 namespace {
 
-constexpr uint64_t default_peer_count = 20;
+constexpr uint64_t default_peer_count = 10;
 
-constexpr uint64_t default_message_count = 10'000'000;
+constexpr uint64_t default_message_count = 10'000;
 
 constexpr uint64_t default_payload_size = 1'000;
 
@@ -187,7 +187,6 @@ void add_options(configuration& cfg, parameters& ps) {
                  "enables more console output");
   cfg.add_option(&ps.naive_publish, "naive-publish",
                  "publish data via endpoint::publish instead of publish_all");
-  ;
 }
 
 struct generator {