Virtual Threads: A Short Note about Naming

Cay Horstmann cay.horstmann at
Fri Nov 22 21:28:14 UTC 2019

Il 21/11/19 20:09, Brian Goetz ha scritto:
>> I agree that naming is important. Not sure "virtual" is a winner 
>> because it has connotations of increased cost.
> ... though those costs are precisely analogous to the costs incurred by 
> virtual threads.  Mounting a virtual thread on, or dismounting from, a 
> real thread requires work to copy stack frames, for example.  These are 
> a precise analog of building and tearing down page tables.

It's certainly a fair point to remind programmers that "fibers"/"virtual 
threads" are not cost free.

When I talked to people about Loom, I didn't think they had a good frame 
of reference when "fibers" would be beneficial. They tended to follow 
"fiber = better thread", which didn't seem useful. I don't think 
"virtual thread" would save that.

Perhaps a better angle would be to use a name that indicates why this 
cost is worth incurring? You wouldn't want to pay for lots of OS threads 
that are mostly blocking. But a "fiber" is parked when it executes a 
blocking call, and we are happy to pay the price of copying stack frames 
in return. Have you considered "BlockingTask" or "Blockable" or 
"Parkable" or some such thing?



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