Source code
Revision control
Copy as Markdown
Other Tools
// Copyright 2024 Google LLC
// SPDX-License-Identifier: Apache-2.0
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "hwy/perf_counters.h"
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <vector>
#include "hwy/contrib/thread_pool/futex.h" // NanoSleep
#include "hwy/nanobenchmark.h" // Unpredictable1
#include "hwy/tests/hwy_gtest.h"
#include "hwy/tests/test_util-inl.h"
#include "hwy/timer.h"
namespace hwy {
namespace {
using ::hwy::platform::PerfCounters;
void ReadAndPrint(uint64_t r, double* values) {
char cpu100[100];
const bool have_stop = hwy::platform::HaveTimerStop(cpu100);
const uint64_t t0 = timer::Start();
PerfCounters counters;
const uint64_t t1 = have_stop ? timer::Stop() : timer::Start();
const double elapsed_ns =
static_cast<double>(t1 - t0) * 1E9 / platform::InvariantTicksPerSecond();
fprintf(stderr, "r: %d, any valid %d extrapolate %f, overhead %.1f ns\n",
static_cast<int>(r), counters.AnyValid(), counters.MaxExtrapolate(),
elapsed_ns);
if (counters.AnyValid()) {
HWY_ASSERT(counters.MaxExtrapolate() >= 1.0);
}
counters.Foreach([&counters, values](double val, PerfCounters::Counter c) {
HWY_ASSERT(counters.IsValid(c));
fprintf(stderr, "%-20s: %.3E\n", PerfCounters::Name(c), val);
values[static_cast<size_t>(c)] = val;
});
PerfCounters::StopAllAndReset();
}
// Ensures a memory-intensive workload has high memory-related counters.
TEST(PerfCountersTest, TestMem) {
RandomState rng;
if (!PerfCounters::Init() || !PerfCounters::StartAll()) {
HWY_WARN("Perf counters unavailable, skipping test\n");
return;
}
// Force L3 cache misses (loads).
std::vector<uint64_t> big_array(128 * 1024 * 1024);
for (uint64_t& x : big_array) {
x = rng() & static_cast<uint64_t>(hwy::Unpredictable1());
}
const uint64_t r = big_array[rng() & 0xFFFF];
double values[64] = {0.0};
ReadAndPrint(r, values);
// Note that counters might not be available, and values differ considerably
// for debug/sanitizer builds.
HWY_ASSERT(values[PerfCounters::kRefCycles] == 0.0 ||
values[PerfCounters::kRefCycles] > 1E8); // 470M..9B
HWY_ASSERT(values[PerfCounters::kInstructions] == 0.0 ||
values[PerfCounters::kInstructions] > 1E5); // 1.5M..10B
HWY_ASSERT(values[PerfCounters::kPageFaults] == 0.0 ||
values[PerfCounters::kPageFaults] > 1); // 4..500K
HWY_ASSERT(values[PerfCounters::kBranches] == 0.0 ||
values[PerfCounters::kBranches] > 1E5); // > 900K
HWY_ASSERT(values[PerfCounters::kBranchMispredicts] < 1E9); // 273K..400M
HWY_ASSERT(values[PerfCounters::kL3Loads] == 0.0 ||
values[PerfCounters::kL3Loads] > 10.0); // ~90K, 50 with L4
HWY_ASSERT(values[PerfCounters::kL3Stores] == 0.0 ||
values[PerfCounters::kL3Stores] > 10.0); // 9K..5M
HWY_ASSERT(values[PerfCounters::kCacheRefs] == 0.0 ||
values[PerfCounters::kCacheRefs] > 1E4); // 75K..66M
HWY_ASSERT(values[PerfCounters::kCacheMisses] == 0.0 ||
values[PerfCounters::kCacheMisses] > 1.0); // 10..51M
HWY_ASSERT(values[PerfCounters::kBusCycles] == 0.0 ||
values[PerfCounters::kBusCycles] > 1E6); // 8M
}
// Ensures a branch-heavy workload has high branch-related counters and not
// too high memory-related counters.
TEST(PerfCountersTest, RunBranches) {
RandomState rng;
if (!PerfCounters::Init() || !PerfCounters::StartAll()) {
HWY_WARN("Perf counters unavailable, skipping test\n");
return;
}
// Branch-heavy, non-constexpr calculation so we see changes to counters.
const size_t iters =
static_cast<size_t>(hwy::Unpredictable1()) * 100000 + (rng() & 1);
uint64_t r = rng();
for (size_t i = 0; i < iters; ++i) {
if (PopCount(rng()) < 36) {
r += rng() & 0xFF;
} else {
// Entirely different operation to ensure there is a branch.
r >>= 1;
}
// Ensure test runs long enough for counter multiplexing to happen.
NanoSleep(100 * 1000);
}
double values[64] = {0.0};
ReadAndPrint(r, values);
// Note that counters might not be available, and values differ considerably
// for debug/sanitizer builds.
HWY_ASSERT(values[PerfCounters::kRefCycles] == 0.0 ||
values[PerfCounters::kRefCycles] > 1E3); // 13K..18M
HWY_ASSERT(values[PerfCounters::kInstructions] == 0.0 ||
values[PerfCounters::kInstructions] > 100.0); // 900..2M
HWY_ASSERT(values[PerfCounters::kBranches] == 0.0 ||
values[PerfCounters::kBranches] > 100.0); // 1K..273K
HWY_ASSERT(values[PerfCounters::kBranchMispredicts] == 0 ||
values[PerfCounters::kBranchMispredicts] > 10.0); // 65..5K
HWY_ASSERT(values[PerfCounters::kL3Loads] < 1E8); // 174K..12M
HWY_ASSERT(values[PerfCounters::kL3Stores] < 1E7); // 44K..1.8M
HWY_ASSERT(values[PerfCounters::kCacheRefs] < 1E9); // 5M..104M
HWY_ASSERT(values[PerfCounters::kCacheMisses] < 1E8); // 500K..10M
HWY_ASSERT(values[PerfCounters::kBusCycles] < 1E11); // 1M..10B
HWY_ASSERT(values[PerfCounters::kPageFaults] < 1E4); // 0..1.1K (in SDE)
}
} // namespace
} // namespace hwy
HWY_TEST_MAIN();