| // Copyright 2019 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. |
| |
| #ifndef ABSL_STRINGS_CORDZ_FUNCTIONS_H_ |
| #define ABSL_STRINGS_CORDZ_FUNCTIONS_H_ |
| |
| #include <stdint.h> |
| |
| #include "absl/base/attributes.h" |
| #include "absl/base/config.h" |
| #include "absl/base/optimization.h" |
| |
| namespace absl { |
| ABSL_NAMESPACE_BEGIN |
| namespace cord_internal { |
| |
| // Returns the current sample rate. This represents the average interval |
| // between samples. |
| int32_t get_cordz_mean_interval(); |
| |
| // Sets the sample rate with the average interval between samples. |
| void set_cordz_mean_interval(int32_t mean_interval); |
| |
| // Enable cordz unless any of the following applies: |
| // - no thread local support |
| // - MSVC build |
| // - Android build |
| // - Apple build |
| // - DLL build |
| // Hashtablez is turned off completely in opensource builds. |
| // MSVC's static atomics are dynamically initialized in debug mode, which breaks |
| // sampling. |
| #if defined(ABSL_HAVE_THREAD_LOCAL) && !defined(_MSC_VER) && \ |
| !defined(ABSL_BUILD_DLL) && !defined(ABSL_CONSUME_DLL) && \ |
| !defined(__ANDROID__) && !defined(__APPLE__) |
| #define ABSL_INTERNAL_CORDZ_ENABLED 1 |
| #endif |
| |
| #ifdef ABSL_INTERNAL_CORDZ_ENABLED |
| |
| // cordz_next_sample is the number of events until the next sample event. If |
| // the value is 1 or less, the code will check on the next event if cordz is |
| // enabled, and if so, will sample the Cord. cordz is only enabled when we can |
| // use thread locals. |
| ABSL_CONST_INIT extern thread_local int64_t cordz_next_sample; |
| |
| // Determines if the next sample should be profiled. If it is, the value pointed |
| // at by next_sample will be set with the interval until the next sample. |
| bool cordz_should_profile_slow(); |
| |
| // Returns true if the next cord should be sampled. |
| inline bool cordz_should_profile() { |
| if (ABSL_PREDICT_TRUE(cordz_next_sample > 1)) { |
| cordz_next_sample--; |
| return false; |
| } |
| return cordz_should_profile_slow(); |
| } |
| |
| // Sets the interval until the next sample (for testing only) |
| void cordz_set_next_sample_for_testing(int64_t next_sample); |
| |
| #else // ABSL_INTERNAL_CORDZ_ENABLED |
| |
| inline bool cordz_should_profile() { return false; } |
| inline void cordz_set_next_sample_for_testing(int64_t) {} |
| |
| #endif // ABSL_INTERNAL_CORDZ_ENABLED |
| |
| } // namespace cord_internal |
| ABSL_NAMESPACE_END |
| } // namespace absl |
| |
| #endif // ABSL_STRINGS_CORDZ_FUNCTIONS_H_ |