google--benchmark/docs/bazel.md

Bazel

Google Benchmark provides Bazel targets for both the benchmark library and the optional default main function:

• @google_benchmark//:benchmark provides the benchmark library.
• @google_benchmark//:benchmark_main provides the default main function and depends on @google_benchmark//:benchmark.

Use @google_benchmark//:benchmark when the benchmark target defines its own main function, including through BENCHMARK_MAIN(). Use @google_benchmark//:benchmark_main when the benchmark target should use the default Google Benchmark entry point.

Bzlmod

With Bzlmod enabled, add Google Benchmark to your MODULE.bazel file:

bazel_dep(name = "google_benchmark", version = "<VERSION>")

Replace <VERSION> with the Google Benchmark release version you want to use.

Then depend on the Bazel target from a cc_binary or cc_test:

load("@rules_cc//cc:defs.bzl", "cc_binary")

cc_binary(
    name = "string_benchmark",
    srcs = ["string_benchmark.cc"],
    deps = ["@google_benchmark//:benchmark_main"],
)

The source file should register benchmarks, but it should not call BENCHMARK_MAIN() when linking against @google_benchmark//:benchmark_main:

#include <benchmark/benchmark.h>
#include <string>

static void BM_StringCreation(benchmark::State& state) {
  for (auto _ : state) {
    std::string empty_string;
  }
}
BENCHMARK(BM_StringCreation);

Run the benchmark with Bazel:

bazel run //:string_benchmark

Pass Google Benchmark flags after Bazel's -- separator:

bazel run //:string_benchmark -- --benchmark_filter=StringCreation

WORKSPACE

Projects that still use WORKSPACE can declare Google Benchmark as an external repository and load its dependencies from bazel/benchmark_deps.bzl:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "google_benchmark",
    strip_prefix = "benchmark-<VERSION>",
    urls = ["https://github.com/google/benchmark/archive/refs/tags/v<VERSION>.tar.gz"],
    # Add sha256 for reproducible builds.
)

load("@google_benchmark//:bazel/benchmark_deps.bzl", "benchmark_deps")

benchmark_deps()

Use the same <VERSION> value without the leading v; the archive URL adds the tag prefix explicitly.

After declaring the repository, use the same target labels shown above: @google_benchmark//:benchmark or @google_benchmark//:benchmark_main.

Perf Counters

When using Bazel, enable libpfm support by adding --define pfm=1 to the build or run command. See Perf Counters for more details.