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Diffstat (limited to 'absl/container/sample_element_size_test.cc')
-rw-r--r-- | absl/container/sample_element_size_test.cc | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/absl/container/sample_element_size_test.cc b/absl/container/sample_element_size_test.cc new file mode 100644 index 00000000..b23626b4 --- /dev/null +++ b/absl/container/sample_element_size_test.cc @@ -0,0 +1,114 @@ +// Copyright 2018 The Abseil Authors. +// +// 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 +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// 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 "gmock/gmock.h" +#include "gtest/gtest.h" +#include "absl/container/flat_hash_map.h" +#include "absl/container/flat_hash_set.h" +#include "absl/container/node_hash_map.h" +#include "absl/container/node_hash_set.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace container_internal { +namespace { + +#if defined(ABSL_INTERNAL_HASHTABLEZ_SAMPLE) +// Create some tables of type `Table`, then look at all the new +// `HashtablezInfo`s to make sure that the `inline_element_size == +// expected_element_size`. The `inline_element_size` is the amount of memory +// allocated for each slot of a hash table, that is `sizeof(slot_type)`. Add +// the new `HashtablezInfo`s to `preexisting_info`. Store all the new tables +// into `tables`. +template <class Table> +void TestInlineElementSize( + HashtablezSampler& sampler, + // clang-tidy gives a false positive on this declaration. This unordered + // set cannot be flat_hash_set, however, since that would introduce a mutex + // deadlock. + std::unordered_set<const HashtablezInfo*>& preexisting_info, // NOLINT + std::vector<Table>& tables, const typename Table::value_type& elt, + size_t expected_element_size) { + for (int i = 0; i < 10; ++i) { + // We create a new table and must store it somewhere so that when we store + // a pointer to the resulting `HashtablezInfo` into `preexisting_info` + // that we aren't storing a dangling pointer. + tables.emplace_back(); + // We must insert an element to get a hashtablez to instantiate. + tables.back().insert(elt); + } + size_t new_count = 0; + sampler.Iterate([&](const HashtablezInfo& info) { + if (preexisting_info.insert(&info).second) { + EXPECT_EQ(info.inline_element_size, expected_element_size); + ++new_count; + } + }); + // Make sure we actually did get a new hashtablez. + EXPECT_GT(new_count, 0); +} + +struct bigstruct { + char a[1000]; + friend bool operator==(const bigstruct& x, const bigstruct& y) { + return memcmp(x.a, y.a, sizeof(x.a)) == 0; + } + template <typename H> + friend H AbslHashValue(H h, const bigstruct& c) { + return H::combine_contiguous(std::move(h), c.a, sizeof(c.a)); + } +}; +#endif + +TEST(FlatHashMap, SampleElementSize) { +#if defined(ABSL_INTERNAL_HASHTABLEZ_SAMPLE) + // Enable sampling even if the prod default is off. + SetHashtablezEnabled(true); + SetHashtablezSampleParameter(1); + + auto& sampler = GlobalHashtablezSampler(); + std::vector<flat_hash_map<int, bigstruct>> flat_map_tables; + std::vector<flat_hash_set<bigstruct>> flat_set_tables; + std::vector<node_hash_map<int, bigstruct>> node_map_tables; + std::vector<node_hash_set<bigstruct>> node_set_tables; + + // It takes thousands of new tables after changing the sampling parameters + // before you actually get some instrumentation. And if you must actually + // put something into those tables. + for (int i = 0; i < 10000; ++i) { + flat_map_tables.emplace_back(); + flat_map_tables.back()[i] = bigstruct{}; + } + + // clang-tidy gives a false positive on this declaration. This unordered set + // cannot be a flat_hash_set, however, since that would introduce a mutex + // deadlock. + std::unordered_set<const HashtablezInfo*> preexisting_info; // NOLINT + sampler.Iterate( + [&](const HashtablezInfo& info) { preexisting_info.insert(&info); }); + TestInlineElementSize(sampler, preexisting_info, flat_map_tables, + {0, bigstruct{}}, sizeof(int) + sizeof(bigstruct)); + TestInlineElementSize(sampler, preexisting_info, node_map_tables, + {0, bigstruct{}}, sizeof(void*)); + TestInlineElementSize(sampler, preexisting_info, flat_set_tables, // + bigstruct{}, sizeof(bigstruct)); + TestInlineElementSize(sampler, preexisting_info, node_set_tables, // + bigstruct{}, sizeof(void*)); +#endif +} + +} // namespace +} // namespace container_internal +ABSL_NAMESPACE_END +} // namespace absl |