sparklemotion/nokogiri

investigate #1970 - string optimization

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#1986 opened on Feb 3, 2020

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help wantedneeds/researchtopic/performance

Description

Background

PR #1970 was opened by @ashmaroli to attempt to reduce the number of allocated empty strings created by Nokogiri.

This PR was merged and released in v1.11.0.rc1.

@ashmaroli repeated his profiling (I think using the memory_profiler gem) and commented that it didn't seem to have an effect.

Actions

  1. reproduce the original memory profliling scenario - @ashmaroli please help with this
  2. determine whether the patch can be tweaked to reduce the number of allocated strings or no
  3. make a recommendation - revert or re-patch

Retrospecting

I should have asked for more details from @ashmaroli when he submitted the PR to reproduce his results, and demonstrate improvement, before merging. This would have allowed me to ask questions at a more appropriate time.

Contributor guide

Tech stack
None
Domain
performance
Issue type
research
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Rubymemory profiler gemnokogiri codebaseC extensions
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Reproduce the memory profiling scenario using the memory profiler gem as described in PR #1970. Review the patch in that PR and determine if it can be tweaked to reduce string allocations. The recommendation should be based on profiling results, either to revert or re patch. See comments from @ashmaroli in the PR for details.