dotnet/runtime

Reduce memory consumption of the JIT by eliminating padding etc

Open

#6,756 opened on Oct 3, 2016

View on GitHub
 (1 comment) (0 reactions) (0 assignees)C# (5,445 forks)batch import
JitThroughputarea-CodeGen-coreclrenhancementhelp wantedtenet-performance

Repository metrics

Stars
 (17,886 stars)
PR merge metrics
 (Avg merge 12d 11h) (661 merged PRs in 30d)

Description

The "struct GenTree_" family is the most obvious example of this, though other important JIT data structures should be checked as well - make sure there is no unnecessary padding (due to data member alignment), see if data members could be rearranged to reduce overall size, and specifically in the case of GenTree_ make sure the sizes of the "small" vs. "large" nodes (and which GenTree* flavors are marked as always having to be "large") are optimized.

category:throughput theme:jit-coding-style skill-level:intermediate cost:small impact:small

Contributor guide

Research direction
Inspect the definition of 'struct GenTree ' in the JIT source code, use compiler options (e.g., /d1reportAllClassLayout) to dump layout and identify padding, then rearrange members or apply padding optimizations to reduce memory footprint.
Tech stack
csharp
Domain
backend
Issue type
Refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
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.
Mostly clear
Prerequisites
C#JIT compiler internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55