add benchmark for sparse cases

benchmarks/CMakeLists.txt

@@ -10,10 +10,10 @@ if(NOT WIN32)
     add_c_benchmark(add_benchmark)
     target_link_libraries(add_benchmark m)
     add_c_benchmark(intersect_range_benchmark)
-    target_link_libraries(add_benchmark m)
     add_c_benchmark(frozen_benchmark)
     add_c_benchmark(containsmulti_benchmark)
     add_cpp_benchmark(fastunion_benchmark)
+    add_cpp_benchmark(sparse_cases_benchmark)
 endif()
 add_c_benchmark(bitset_container_benchmark)
 add_c_benchmark(array_container_benchmark)

benchmarks/sparse_cases_benchmark.cpp

@@ -0,0 +1,52 @@
+#include <roaring/roaring.h>
+
+#include <iostream>
+#include <random>
+#include <roaring64map.hh>
+
+#include "benchmark.h"
+
+// the same key will add to the same bitmap
+static std::default_random_engine e;
+
+void run_bench(size_t batch_size, int loop_count, size_t max) {
+    using namespace roaring;
+    using roaring::Roaring;
+    std::uniform_int_distribution<uint64_t> dist(0, max);
+    uint64_t cycles_start, cycles_final;
+    RDTSC_START(cycles_start);
+    for (int j = 0; j < loop_count ; ++j) {
+        Roaring64Map bitmap_64;
+        for (size_t i = 0; i < batch_size; i++) {
+            bitmap_64.add(dist(e));
+        }
+    }
+
+    RDTSC_FINAL(cycles_final);
+    std::cout << "batch_size=" << batch_size << ", max=" << max << " costs:"
+              << (cycles_final - cycles_start) * 1.0 / batch_size / loop_count
+              << std::endl;
+}
+
+int main(int argc, char* argv[]) {
+    (void)argc;
+    (void)argv;
+
+    run_bench(100, 10, 100);
+    run_bench(100, 10, 1000);
+    run_bench(100, 10, 1000000);
+    run_bench(100, 10, 100000000);
+    run_bench(100, 10, 10000000000);
+
+    run_bench(100000, 10, 1000);
+    run_bench(100000, 10, 100000);
+    run_bench(100000, 10, 1000000000);
+    run_bench(100000, 10, 100000000000);
+
+    run_bench(100000000, 1, 100000000);
+    run_bench(100000000, 1, 500000000);
+    run_bench(100000000, 1, 5000000000);
+
+
+    return 0;
+}