diff --git a/test/perf/perf.cc b/test/perf/perf.cc
index 1e08519677..389e94284c 100644
--- a/test/perf/perf.cc
+++ b/test/perf/perf.cc
@@ -30,11 +30,12 @@ void scheduling_latency_measurer::schedule_tick() {
     }));
 }
 
-std::ostream& operator<<(std::ostream& out, const scheduling_latency_measurer& slm) {
+auto fmt::formatter<scheduling_latency_measurer>::format(const scheduling_latency_measurer& slm, fmt::format_context& ctx) const
+        -> decltype(ctx.out()) {
     auto to_ms = [] (int64_t nanos) {
         return float(nanos) / 1e6;
     };
-    return out << fmt::format("{{count: {}, "
+    return fmt::format_to(ctx.out(), "{{count: {}, "
                          //"min: {:.6f} [ms], "
                          //"50%: {:.6f} [ms], "
                          //"90%: {:.6f} [ms], "
@@ -48,11 +49,10 @@ std::ostream& operator<<(std::ostream& out, const scheduling_latency_measurer& s
         to_ms(slm.max().count()));
 }
 
-std::ostream&
-operator<<(std::ostream& os, const perf_result& result) {
-    fmt::print(os, "{:.2f} tps ({:5.1f} allocs/op, {:5.1f} tasks/op, {:7.0f} insns/op, {:8} errors)",
+auto fmt::formatter<perf_result>::format(const perf_result& result, fmt::format_context& ctx) const
+        -> decltype(ctx.out()) {
+    return fmt::format_to(ctx.out(), "{:.2f} tps ({:5.1f} allocs/op, {:5.1f} tasks/op, {:7.0f} insns/op, {:8} errors)",
             result.throughput, result.mallocs_per_op, result.tasks_per_op, result.instructions_per_op, result.errors);
-    return os;
 }
 
 aio_writes_result_mixin::aio_writes_result_mixin()
diff --git a/test/perf/perf.hh b/test/perf/perf.hh
index ca1418666b..6ca495c2a3 100644
--- a/test/perf/perf.hh
+++ b/test/perf/perf.hh
@@ -157,8 +157,6 @@ struct perf_result {
     uint64_t errors;
 };
 
-std::ostream& operator<<(std::ostream& os, const perf_result& result);
-
 // Use to make a perf_result with aio_writes added. Need to give "update" as
 // update-func to time_parallel_ex to make it work.
 struct aio_writes_result_mixin {
@@ -213,7 +211,7 @@ std::vector<Res> time_parallel_ex(Func func, unsigned concurrency_per_core, int
 
         uf(result, stats);
 
-        std::cout << result << std::endl;
+        fmt::print("{}\n", result);
         results.emplace_back(result);
     }
     return results;
@@ -282,3 +280,11 @@ public:
 };
 
 } // namespace perf
+
+template <> struct fmt::formatter<scheduling_latency_measurer> : fmt::formatter<std::string_view> {
+    auto format(const scheduling_latency_measurer&, fmt::format_context& ctx) const -> decltype(ctx.out());
+};
+
+template <> struct fmt::formatter<perf_result> : fmt::formatter<std::string_view> {
+    auto format(const perf_result&, fmt::format_context& ctx) const -> decltype(ctx.out());
+};