google/benchmark

benchmark::MakeUnpredictable

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#341 opened on Feb 11, 2017

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 (13 comments) (0 reactions) (1 assignee)C++ (1,539 forks)batch import
enhancementhelp wantedincomplete

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Description

folly::benchmark includes makeUnpredictable function to hide a compile-time constant value of a variable from optimizer. This is a very useful feature, and google::benchmark should provide something similar.

Contributor guide

Research direction
Implement a function similar to folly::makeUnpredictable using compiler barriers or inline assembly to prevent constant propagation. Research compiler specific intrinsics like ` asm volatile` or ` builtin unpredictable`.
Tech stack
cpp
Domain
tooling
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65