Issue #6865 has been reported by Eregon (Benoit Daloze).

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Bug #6865: GC::Profiler.report might create a huge String and invoke a few GC cycles
https://bugs.ruby-lang.org/issues/6865

Author: Eregon (Benoit Daloze)
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 
ruby -v: ruby 2.0.0dev (2012-08-10 trunk 36676) [x86_64-darwin10.8.0]


Hi,

In my use-case, GC::Profiler.report adds a few GC cycles to actually create the report, ending with these lines:

 9317              26.279               185760               701760                17544         0.33300000000124896360
 9318              26.282               185760               701760                17544         0.32800000000321460902
# start of GC::Profiler.report
 9319              26.285               393400               701760                17544         0.82300000000046225068
 9320              26.288               700480               718080                17952         1.43599999999821648089
 9321              26.294              1254800              1272960                31824         2.69300000000072259354
...
 9331              26.907             43836160             43917120              1097928        81.77799999999990632205

This is likely expected with GC::Profiler.result, but I think it could be partly avoided by printing line by line in GC::Profiler.report. Maybe gc_profile_result() could accepts a String or IO as an argument and call #<< or similar ?

I might have a try to solve this, but I'd be happy as well if someone solves it before me.
The GC::Profiler class documentation should probably be updated to use GC::Profiler.report if it proves to be more efficient.


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