[MESOS-4566] Avoid unnecessary temporary `std::string` constructions and copies in `jsonify`.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.24.2, 0.25.1, 0.26.1, 0.27.1, 0.28.0
• Component/s: stout
• Labels: mesosphere
• Target Version/s: 0.28.0
• Epic Link: json-perf
• Sprint: Mesosphere Sprint 27
• Story Points: 1
• Assignee: Michael Park
• Reporter: Michael Park
• Shepherd: Joris Van Remoortere
• Created: 31/Jan/16 00:05
• Updated: 26/Nov/18 12:22
• Resolved: 26/Nov/18 12:22

Description

A few of the critical code paths in jsonify involve unnecessary temporary string construction and copies (inherited from the JSON::*). For example, strings::trim is used to remove trailing 0s from printing double. We print double a lot, and therefore constructing a temporary std::string on printing of every double is extremely costly. This ticket captures the work involved in avoiding them.