Issue #7161 has been updated by headius (Charles Nutter).


The performance gain is not tremendous, but it does avoid a lot of intermediate string objects that could cumulatively impact performance through GC overhead.

In any case, it's a good cleanup patch, and there are certainly small perf gains.
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Bug #7161: Perf fix: use symbols instead of strings for const/ivar access methods
https://bugs.ruby-lang.org/issues/7161#change-32452

Author: headius (Charles Nutter)
Status: Assigned
Priority: Normal
Assignee: shyouhei (Shyouhei Urabe)
Category: 
Target version: 
ruby -v: 2.0.0


From pull request: https://github.com/ruby/ruby/pull/195

Fixes a number of places where literal, non-dynamic strings are used as the first argument for constant and instance variable get, set, and defined? methods. This reduces object overhead in all cases.

Notable fixes:

* Setting @original_filename and @content_type in read_multipart (cgi/core.rb). This is called for every multipart read.
* Setting @uri and @ref in DrbObject.new_with (drb/drb.rb). Called for every "with" instantiation of a DrbObject.
* Setting BINDING_QUEUE in IRB::Workspace#initialize (irb/workspace.rb). Called for every new IRB workspace.
* Getting @mon_mutex in ConditionVariable#wait (monitor.rb). Called for every #wait. This fix makes the method require zero object allocation (other than imposed by the runtime).

The other fixes are rarely called, but fixed for consistency.

make test-all passes the same with or without this patch.


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