Necessary Maintenance #5281: Move to using make_shared() wherever possible and appropriate. - art - Fermilab Redmine

Necessary Maintenance #5281

Move to using make_shared() wherever possible and appropriate.

Added by Christopher Green over 6 years ago. Updated 10 months ago.

Status:

Closed

Priority:

Low

Assignee:

Category:

Infrastructure

Target version:

Start date:

01/28/2014

Due date:

% Done:

100%

Estimated time:

8.00 h

Scope:

Experiment:

SSI Package:

Duration:

Description

make_shared(), when used consistently in preference to shared_ptr<>(new ...), is significantly faster. Where it is straightforward to do, we should do this.

History

#1 Updated by Rob Kutschke over 6 years ago

Chris: maybe a short presentation at the stakeholders meeting would be a good idea? What's going on under the covers and where, in typical experimental code, is it important.

#2 Updated by Christopher Green over 6 years ago

Status changed from New to Accepted
Priority changed from Normal to Low
Estimated time set to 8.00 h

This is a, "low-hanging fruit" issue, making the code conform to current best practice and getting a performance improvement into the bargain. Basically the idea is to take advantage of the fact that make_shared allocates the memory for the reference counter contiguous with the saved object, and reducing the number of unnecessary shared_ptr copies by using references reduces the churn on the reference counter, thereby also improving performance. If experiments wish to do this in their own code there should be no issues with respect to whether or not art does the same thing (or vice versa).