Abseil Common Libraries (C++) (grcp 依赖)
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85 lines
2.8 KiB
85 lines
2.8 KiB
// Copyright 2019 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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#ifndef ABSL_STRINGS_CORDZ_FUNCTIONS_H_ |
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#define ABSL_STRINGS_CORDZ_FUNCTIONS_H_ |
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#include <stdint.h> |
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#include "absl/base/attributes.h" |
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#include "absl/base/config.h" |
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#include "absl/base/optimization.h" |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace cord_internal { |
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// Returns the current sample rate. This represents the average interval |
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// between samples. |
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int32_t get_cordz_mean_interval(); |
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// Sets the sample rate with the average interval between samples. |
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void set_cordz_mean_interval(int32_t mean_interval); |
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// Enable cordz unless any of the following applies: |
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// - no thread local support |
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// - MSVC build |
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// - Android build |
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// - Apple build |
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// - DLL build |
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// Hashtablez is turned off completely in opensource builds. |
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// MSVC's static atomics are dynamically initialized in debug mode, which breaks |
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// sampling. |
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#if defined(ABSL_HAVE_THREAD_LOCAL) && !defined(_MSC_VER) && \ |
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!defined(ABSL_BUILD_DLL) && !defined(ABSL_CONSUME_DLL) && \ |
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!defined(__ANDROID__) && !defined(__APPLE__) |
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#define ABSL_INTERNAL_CORDZ_ENABLED 1 |
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#endif |
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#ifdef ABSL_INTERNAL_CORDZ_ENABLED |
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// cordz_next_sample is the number of events until the next sample event. If |
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// the value is 1 or less, the code will check on the next event if cordz is |
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// enabled, and if so, will sample the Cord. cordz is only enabled when we can |
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// use thread locals. |
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ABSL_CONST_INIT extern thread_local int64_t cordz_next_sample; |
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// Determines if the next sample should be profiled. If it is, the value pointed |
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// at by next_sample will be set with the interval until the next sample. |
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bool cordz_should_profile_slow(); |
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// Returns true if the next cord should be sampled. |
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inline bool cordz_should_profile() { |
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if (ABSL_PREDICT_TRUE(cordz_next_sample > 1)) { |
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cordz_next_sample--; |
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return false; |
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} |
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return cordz_should_profile_slow(); |
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} |
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// Sets the interval until the next sample (for testing only) |
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void cordz_set_next_sample_for_testing(int64_t next_sample); |
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#else // ABSL_INTERNAL_CORDZ_ENABLED |
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inline bool cordz_should_profile() { return false; } |
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inline void cordz_set_next_sample_for_testing(int64_t) {} |
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#endif // ABSL_INTERNAL_CORDZ_ENABLED |
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} // namespace cord_internal |
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ABSL_NAMESPACE_END |
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} // namespace absl |
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#endif // ABSL_STRINGS_CORDZ_FUNCTIONS_H_
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