rocksdb/third-party/folly/folly/ConstexprMath.h
Peter Dillinger 68626249c3 Refactor/consolidate legacy Bloom implementation details (#5784)
Summary:
Refactoring to consolidate implementation details of legacy
Bloom filters. This helps to organize and document some related,
obscure code.

Also added make/cpp var TEST_CACHE_LINE_SIZE so that it's easy to
compile and run unit tests for non-native cache line size. (Fixed a
related test failure in db_properties_test.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5784

Test Plan:
make check, including Recently added Bloom schema unit tests
(in ./plain_table_db_test && ./bloom_test), and including with
TEST_CACHE_LINE_SIZE=128U and TEST_CACHE_LINE_SIZE=256U. Tested the
schema tests with temporary fault injection into new implementations.

Some performance testing with modified unit tests suggest a small to moderate
improvement in speed.

Differential Revision: D17381384

Pulled By: pdillinger

fbshipit-source-id: ee42586da996798910fc45ac0b6289147f16d8df
2019-09-16 16:17:09 -07:00

46 lines
1.1 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
namespace folly {
template <typename T>
constexpr T constexpr_max(T a) {
return a;
}
template <typename T, typename... Ts>
constexpr T constexpr_max(T a, T b, Ts... ts) {
return b < a ? constexpr_max(a, ts...) : constexpr_max(b, ts...);
}
namespace detail {
template <typename T>
constexpr T constexpr_log2_(T a, T e) {
return e == T(1) ? a : constexpr_log2_(a + T(1), e / T(2));
}
template <typename T>
constexpr T constexpr_log2_ceil_(T l2, T t) {
return l2 + T(T(1) << l2 < t ? 1 : 0);
}
template <typename T>
constexpr T constexpr_square_(T t) {
return t * t;
}
} // namespace detail
template <typename T>
constexpr T constexpr_log2(T t) {
return detail::constexpr_log2_(T(0), t);
}
template <typename T>
constexpr T constexpr_log2_ceil(T t) {
return detail::constexpr_log2_ceil_(constexpr_log2(t), t);
}
} // namespace folly