| 1 | //===- llvm/Support/ExponentialBackoff.h ------------------------*- C++ -*-===// |
|---|---|
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | #include "llvm/Support/ExponentialBackoff.h" |
| 10 | #include <thread> |
| 11 | |
| 12 | using namespace llvm; |
| 13 | |
| 14 | bool ExponentialBackoff::waitForNextAttempt() { |
| 15 | auto Now = std::chrono::steady_clock::now(); |
| 16 | if (Now >= EndTime) |
| 17 | return false; |
| 18 | |
| 19 | duration CurMaxWait = std::min(a: MinWait * CurrentMultiplier, b: MaxWait); |
| 20 | std::uniform_int_distribution<uint64_t> Dist(MinWait.count(), |
| 21 | CurMaxWait.count()); |
| 22 | // Use random_device directly instead of a PRNG as uniform_int_distribution |
| 23 | // often only takes a few samples anyway. |
| 24 | duration WaitDuration = std::min(a: duration(Dist(RandDev)), b: EndTime - Now); |
| 25 | if (CurMaxWait < MaxWait) |
| 26 | CurrentMultiplier *= 2; |
| 27 | std::this_thread::sleep_for(rtime: WaitDuration); |
| 28 | return true; |
| 29 | } |
| 30 |