| /* |
| * Copyright 2019 Google LLC |
| * |
| * Licensed under both the 3-Clause BSD License and the GPLv2, found in the |
| * LICENSE and LICENSE.GPL-2.0 files, respectively, in the root directory. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
| */ |
| |
| #ifndef DEMOS_ASM_MEASUREREADLATENCY_H_ |
| #define DEMOS_ASM_MEASUREREADLATENCY_H_ |
| |
| #include <cstdint> |
| |
| // Reads a byte from *address and returns a measure of how long it took by |
| // sampling a platform timer before and after the read. |
| // |
| // The measurement may include the time it took to execute some other |
| // instructions, but implementations go to some trouble to ensure all |
| // *variability* across measurements is due to the latency of the memory read. |
| // |
| // See README.md and platform-specific implementations for more discussion. |
| // |
| // Will return spuriously high results if e.g. the thread is preempted while |
| // measuring the read. |
| extern "C" uint64_t MeasureReadLatency(const void* address); |
| |
| #endif // DEMOS_ASM_MEASUREREADLATENCY_H_ |
