Feature #8263

Support discovering yield state of individual Fibers

Added by Tim Carey-Smith about 3 years ago. Updated about 3 years ago.



Related to #8215, when debugging a multi-Fiber application or library it is useful to be able to look at the stack for the (({Thread})) which is possible right now.
Currently it is not possible to discover where the Fiber was yielded.

Is this something that could be added?



#1 [ruby-core:54456] Updated by Tim Carey-Smith about 3 years ago

Should this be in common-ruby?
Could someone move it?

#2 Updated by Aman Gupta about 3 years ago

  • Project changed from Ruby trunk to CommonRuby

#3 [ruby-core:54461] Updated by Tim Carey-Smith about 3 years ago

There was some confusion about what I am proposing.
I realised I didn't even explain this!

I would like to be able to see the backtrace of individual Fibers.
This would allow our Celluloid.stack_dump to show each point at which the Fibers are waiting.

#4 [ruby-core:54479] Updated by Tim Carey-Smith about 3 years ago

I have implemented Fiber#backtrace in Rubinius and have a demo of what I wanted to achieve.

This depends on another change, Thread#root_fiber, which returns the root_fiber of the specified Thread.

#5 [ruby-core:54635] Updated by Koichi Sasada about 3 years ago

  • Assignee set to Koichi Sasada

Sorry, I can't understand what is your proposal.

At first example,
there is only "thread.backtrace". However, we have already Thread#backtrace.

p Thread.current.backtrace
ruby 2.1.0dev (2013-03-18 trunk 39808) [i386-mswin32_100]
["t.rb:2:in backtrace'", "t.rb:2:in'"]

BTW, please add more specific description.

For example, Rdoc style description for proposed methods
is very welcome because we can understand your proposal
and we (especially I, who is not good English writer)
can copy this document to implemented source code!

#6 [ruby-core:54651] Updated by Tim Carey-Smith about 3 years ago

When you have many Fibers inside a Thread.
You cannot find where the FIbers are currently suspended.

I propose adding a method to Fiber to return this information.

Calling Fiber.current.backtrace would be equivalent to Thread.current.backtrace due to the nature of Fibers.

Does this help with understanding?

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