New upstream version 6.0.20upstream

1 files changed, 144 insertions, 0 deletions

diff --git a/src/mongo/db/query/query_stats/rate_limiting_bm.cpp b/src/mongo/db/query/query_stats/rate_limiting_bm.cpp
new file mode 100644
index 00000000000..06308e6b0d8
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+++ b/src/mongo/db/query/query_stats/rate_limiting_bm.cpp
@@ -0,0 +1,144 @@
+/**
+ *    Copyright (C) 2023-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+
+#include <benchmark/benchmark.h>
+#include <climits>
+#include <memory>
+
+#include "mongo/bson/json.h"
+#include "mongo/db/matcher/expression_leaf.h"
+#include "mongo/db/matcher/expression_parser.h"
+#include "mongo/db/query/query_shape/query_shape.h"
+#include "mongo/db/query/query_stats/rate_limiting.h"
+#include "mongo/util/duration.h"
+#include "mongo/util/processinfo.h"
+#include "mongo/util/time_support.h"
+
+namespace mongo {
+namespace {
+
+// Local testing determined that these parameter values drove the most lock contention, which is
+// what we want to capture in this benchmark.
+constexpr long long rateLimitedWorkTimeMicros = 5;
+constexpr long long consistentWorkTimeMicros = 10;
+
+constexpr long long numThreads = 256;
+
+// Rate limit some fraction of the overall work for a request with a sliding window.
+int requestWithSlidingWindow(RateLimiting& limit) {
+    if (limit.handleRequestSlidingWindow()) {
+        sleepmicros(rateLimitedWorkTimeMicros);
+    }
+    sleepmicros(consistentWorkTimeMicros);
+    return 0;
+}
+
+// Represent a request that bypasses the rate limiter.
+int requestUnlimited() {
+    constexpr long long totalTime = rateLimitedWorkTimeMicros + consistentWorkTimeMicros;
+    sleepmicros(totalTime);
+    return 0;
+}
+
+// Represent a request without the rate limited work.
+int requestDeactivated() {
+    sleepmicros(consistentWorkTimeMicros);
+    return 0;
+}
+
+// Benchmark sliding window rate limiting.
+void BM_SlidingWindow(benchmark::State& state) {
+    // The rate limiter needs a clock source passed in.
+    static std::unique_ptr<ClockSource> clockSource;
+    static std::unique_ptr<RateLimiting> rateLimit;
+
+    // Initialize the rate limiter only on the first thread to start up.
+    if (state.thread_index == 0) {
+        clockSource = std::make_unique<SystemClockSource>();
+        rateLimit =
+            std::make_unique<RateLimiting>(state.range(0), Milliseconds(1), clockSource.get());
+    }
+
+    // Run the benchmark.
+    for (auto keepRunning : state) {
+        benchmark::DoNotOptimize(requestWithSlidingWindow(*rateLimit));
+    }
+
+    // Clean up the rate limiter when the benchmark is done.
+    if (state.thread_index == 0) {
+        rateLimit.reset();
+        clockSource.reset();
+    }
+}
+
+// "Control" benchmark that does not rate limit requests. In other words, the extra work is always
+// done for every request. This benchmark can be thought of as the "goal" performance for the peak,
+// or the highest rate limit in BM_SlidingWindow, to compare against.
+void BM_Unlimited(benchmark::State& state) {
+    for (auto keepRunning : state) {
+        benchmark::DoNotOptimize(requestUnlimited());
+    }
+}
+// Another control benchmark, where the extra work is never done for any request. This can be
+// thought of as the goal performance for when rate limit equals 0.
+void BM_Deactivated(benchmark::State& state) {
+    for (auto keepRunning : state) {
+        benchmark::DoNotOptimize(requestDeactivated());
+    }
+}
+
+// Google microbenchmarks report time T (in nanoseconds) spent per operation. But at Mongo we are
+// interested in total opereations performed per second. The former can easily be converted to the
+// latter by diving 10^6 by T. Use this benchmark to determine the natural throughput of the
+// operation. This can be compared to the rate limited benchmarks (BM_SlidingWindow) to determine
+// the overhead of rate limiting. Looking at the percentage change in throughput between the control
+// benchmarks and the rate limited benchmark, will indicate how much overhead is due to lock
+// contention.
+BENCHMARK(BM_Unlimited)->Threads(numThreads);
+
+BENCHMARK(BM_Deactivated)->Threads(numThreads);
+
+// Local testing has confirmed that the higher the rate limit, the worse the throughput. This makes
+// sense as putting a higher upper bound on number of requests allowed in a given time period, means
+// longer wait times for the lock.
+BENCHMARK(BM_SlidingWindow)
+    ->ArgName("rate limit")
+    ->Arg(0)
+    ->Arg(64)
+    ->Arg(128)
+    ->Arg(256)
+    ->Arg(512)
+    ->Arg(1024)
+    ->Arg(2048)
+    ->Arg(4816)
+    ->Threads(numThreads);
+
+}  // namespace
+}  // namespace mongo