Bug #7161

Perf fix: use symbols instead of strings for const/ivar access methods

Added by headius (Charles Nutter) over 7 years ago. Updated over 7 years ago.

Target version:
ruby -v:


From pull request:

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 (Uri Gorelik) 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.

Updated by mame (Yusuke Endoh) over 7 years ago

  • Status changed from Open to Assigned
  • Assignee set to shyouhei (Shyouhei Urabe)

The patch looks benign. I wonder how much is the performance improved, though.
Urabe-san, could you handle the pull request?

Yusuke Endoh

Updated by headius (Charles Nutter) over 7 years ago

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.

Updated by marcandre (Marc-Andre Lafortune) over 7 years ago

  • Category set to lib
  • Status changed from Assigned to Closed

Committed as r37688.

I'm sorry, I should have added 'patch by Charles Nutter' to the commit log but I forgot that although git can track authors, svn does not.

Updated by headius (Charles Nutter) over 7 years ago

I'll forgive you this time, Marc-Andre :)

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