Issue #7429 has been reported by headius (Charles Nutter). ---------------------------------------- Bug #7429: Provide options for core collections to customize behavior https://bugs.ruby-lang.org/issues/7429 Author: headius (Charles Nutter) Status: Open Priority: Normal Assignee: Category: Target version: 2.0.0 ruby -v: 2.0.0 Many folks know that Matz is a fan of having a few classes that handle a wide range of behavior. For this reason, I think we're unlikely to get a set of parallelism-safe collections added to Ruby. I propose an alternative that would allow parallel-executing implementations to offer concurrency-friendly versions without impact to any code. I would like to see a way to pass in an options hash to the .new construction of at least Hash and Array. For example: # Create a hash that is concurrenct-safe, resizes when density is > 3 keys per bucket, # and sets initial bucket count to 60 hsh = Hash.new(concurrent: true, density: 3, size: 60) Similar for Array: ary = Array.new(concurrent: true, size: 100) Options like density and size map directly to current implementation details of Hash and Array that are sometimes not accessible (you can't change the load factor for Hash, for example). Options like concurrent could be noops on MRI but would allow other implementations to provide safe versions of the collections behind the scenes. I know it may be too late for 2.0.0, but we implementers of parallel-executing Rubies feel the pain of thread-unsafe core structures every day. I think the ability to get thread-safe collections in Ruby core would go a long way toward dispelling the myth that Ruby is bad for concurrent application programming.
on 2012-11-24 17:50
on 2012-11-25 13:54
Issue #7429 has been updated by matz (Yukihiro Matsumoto). Status changed from Open to Rejected Even though I prefer smaller set of built-in fundamental classes, I don't think 'concurrent' option is sufficient, since it requires totally different implementation. I think it's rather better for you to propose 'ParallelHash' etc. Matz. ---------------------------------------- Feature #7429: Provide options for core collections to customize behavior https://bugs.ruby-lang.org/issues/7429#change-33857 Author: headius (Charles Nutter) Status: Rejected Priority: Normal Assignee: Category: Target version: 2.0.0 Many folks know that Matz is a fan of having a few classes that handle a wide range of behavior. For this reason, I think we're unlikely to get a set of parallelism-safe collections added to Ruby. I propose an alternative that would allow parallel-executing implementations to offer concurrency-friendly versions without impact to any code. I would like to see a way to pass in an options hash to the .new construction of at least Hash and Array. For example: # Create a hash that is concurrenct-safe, resizes when density is > 3 keys per bucket, # and sets initial bucket count to 60 hsh = Hash.new(concurrent: true, density: 3, size: 60) Similar for Array: ary = Array.new(concurrent: true, size: 100) Options like density and size map directly to current implementation details of Hash and Array that are sometimes not accessible (you can't change the load factor for Hash, for example). Options like concurrent could be noops on MRI but would allow other implementations to provide safe versions of the collections behind the scenes. I know it may be too late for 2.0.0, but we implementers of parallel-executing Rubies feel the pain of thread-unsafe core structures every day. I think the ability to get thread-safe collections in Ruby core would go a long way toward dispelling the myth that Ruby is bad for concurrent application programming.
on 2012-11-25 15:20
Issue #7429 has been updated by trans (Thomas Sawyer).
=begin
I wonder if concurrency behavior can be designed as a mixin. As long as
the underlying class conforms to its interface then "ParallelWhatever"
becomes possible. ParallelHash would then not be needed as a built-in
class b/c it would be simple to define.
class MyParallelHash < Hash
include Concurrency
end
=end
----------------------------------------
Feature #7429: Provide options for core collections to customize
behavior
https://bugs.ruby-lang.org/issues/7429#change-33860
Author: headius (Charles Nutter)
Status: Rejected
Priority: Normal
Assignee:
Category:
Target version: 2.0.0
Many folks know that Matz is a fan of having a few classes that handle a
wide range of behavior. For this reason, I think we're unlikely to get a
set of parallelism-safe collections added to Ruby. I propose an
alternative that would allow parallel-executing implementations to offer
concurrency-friendly versions without impact to any code.
I would like to see a way to pass in an options hash to the .new
construction of at least Hash and Array. For example:
# Create a hash that is concurrenct-safe, resizes when density is > 3
keys per bucket,
# and sets initial bucket count to 60
hsh = Hash.new(concurrent: true, density: 3, size: 60)
Similar for Array:
ary = Array.new(concurrent: true, size: 100)
Options like density and size map directly to current implementation
details of Hash and Array that are sometimes not accessible (you can't
change the load factor for Hash, for example). Options like concurrent
could be noops on MRI but would allow other implementations to provide
safe versions of the collections behind the scenes.
I know it may be too late for 2.0.0, but we implementers of
parallel-executing Rubies feel the pain of thread-unsafe core structures
every day. I think the ability to get thread-safe collections in Ruby
core would go a long way toward dispelling the myth that Ruby is bad for
concurrent application programming.
on 2012-11-25 19:23
Issue #7429 has been updated by headius (Charles Nutter). matz (Yukihiro Matsumoto) wrote: > Even though I prefer smaller set of built-in fundamental classes, I don't think 'concurrent' option is sufficient, > since it requires totally different implementation. I think it's rather better for you to propose 'ParallelHash' etc. That was indeed my intention; concurrent: true would allow using a completely different implementation under the covers, allowing for an efficient concurrent hash/array (rather than one that simply locks on all accesses). I will repropose as new collection types. Is there any chance of getting them into 2.0.0? ---------------------------------------- Feature #7429: Provide options for core collections to customize behavior https://bugs.ruby-lang.org/issues/7429#change-33865 Author: headius (Charles Nutter) Status: Rejected Priority: Normal Assignee: Category: Target version: 2.0.0 Many folks know that Matz is a fan of having a few classes that handle a wide range of behavior. For this reason, I think we're unlikely to get a set of parallelism-safe collections added to Ruby. I propose an alternative that would allow parallel-executing implementations to offer concurrency-friendly versions without impact to any code. I would like to see a way to pass in an options hash to the .new construction of at least Hash and Array. For example: # Create a hash that is concurrenct-safe, resizes when density is > 3 keys per bucket, # and sets initial bucket count to 60 hsh = Hash.new(concurrent: true, density: 3, size: 60) Similar for Array: ary = Array.new(concurrent: true, size: 100) Options like density and size map directly to current implementation details of Hash and Array that are sometimes not accessible (you can't change the load factor for Hash, for example). Options like concurrent could be noops on MRI but would allow other implementations to provide safe versions of the collections behind the scenes. I know it may be too late for 2.0.0, but we implementers of parallel-executing Rubies feel the pain of thread-unsafe core structures every day. I think the ability to get thread-safe collections in Ruby core would go a long way toward dispelling the myth that Ruby is bad for concurrent application programming.
on 2012-11-25 19:26
Issue #7429 has been updated by headius (Charles Nutter). trans (Thomas Sawyer) wrote: > I wonder if concurrency behavior can be designed as a mixin. As long as the underlying class conforms to its interface then "ParallelWhatever" becomes possible. ParallelHash would then not be needed as a built-in class b/c it would be simple to define. > > class MyParallelHash < Hash > include Concurrency > end Actually, JRuby already provides this as JRuby::Synchronized: class MyParallelHash < Hash include JRuby::Synchronized end It's rather hacky though for a few reasons: * In JRuby, the JRuby::Synchronized module inserts itself into the method lookup process, returning all methods wrapped with synchronization against the target object. * The synchronization is very coarse-grained and much slower than other implementations of a concurrent data structure that would use fewer (or no) locks. * It is not common to have the inclusion of a module change the nature of every method in the host class. It would be better if we had some fast, always-concurrent data structures built in. ---------------------------------------- Feature #7429: Provide options for core collections to customize behavior https://bugs.ruby-lang.org/issues/7429#change-33866 Author: headius (Charles Nutter) Status: Rejected Priority: Normal Assignee: Category: Target version: 2.0.0 Many folks know that Matz is a fan of having a few classes that handle a wide range of behavior. For this reason, I think we're unlikely to get a set of parallelism-safe collections added to Ruby. I propose an alternative that would allow parallel-executing implementations to offer concurrency-friendly versions without impact to any code. I would like to see a way to pass in an options hash to the .new construction of at least Hash and Array. For example: # Create a hash that is concurrenct-safe, resizes when density is > 3 keys per bucket, # and sets initial bucket count to 60 hsh = Hash.new(concurrent: true, density: 3, size: 60) Similar for Array: ary = Array.new(concurrent: true, size: 100) Options like density and size map directly to current implementation details of Hash and Array that are sometimes not accessible (you can't change the load factor for Hash, for example). Options like concurrent could be noops on MRI but would allow other implementations to provide safe versions of the collections behind the scenes. I know it may be too late for 2.0.0, but we implementers of parallel-executing Rubies feel the pain of thread-unsafe core structures every day. I think the ability to get thread-safe collections in Ruby core would go a long way toward dispelling the myth that Ruby is bad for concurrent application programming.
on 2012-11-25 19:45
Issue #7429 has been updated by trans (Thomas Sawyer). That is interesting. I suspect part of the problem is the design of the Hash class itself --something I addressed before in #6442. If Hash had a core set of non-reducible methods which all the others depended, then those should be the only methods that would need to be targeted. Also, #prepend might be handy here, rather than "inserts itself into the method lookup process". Speed isn't everything. I think good design is at least, if not more, important. ---------------------------------------- Feature #7429: Provide options for core collections to customize behavior https://bugs.ruby-lang.org/issues/7429#change-33867 Author: headius (Charles Nutter) Status: Rejected Priority: Normal Assignee: Category: Target version: 2.0.0 Many folks know that Matz is a fan of having a few classes that handle a wide range of behavior. For this reason, I think we're unlikely to get a set of parallelism-safe collections added to Ruby. I propose an alternative that would allow parallel-executing implementations to offer concurrency-friendly versions without impact to any code. I would like to see a way to pass in an options hash to the .new construction of at least Hash and Array. For example: # Create a hash that is concurrenct-safe, resizes when density is > 3 keys per bucket, # and sets initial bucket count to 60 hsh = Hash.new(concurrent: true, density: 3, size: 60) Similar for Array: ary = Array.new(concurrent: true, size: 100) Options like density and size map directly to current implementation details of Hash and Array that are sometimes not accessible (you can't change the load factor for Hash, for example). Options like concurrent could be noops on MRI but would allow other implementations to provide safe versions of the collections behind the scenes. I know it may be too late for 2.0.0, but we implementers of parallel-executing Rubies feel the pain of thread-unsafe core structures every day. I think the ability to get thread-safe collections in Ruby core would go a long way toward dispelling the myth that Ruby is bad for concurrent application programming.
on 2012-11-25 19:57
Issue #7429 has been updated by headius (Charles Nutter). Speed isn't everything...until it becomes everything. Ruby should not be wasteful unnecessarily. There are also immutable truths about data structure implementation, like the fact that adding thread-safety to most data structures comes at a cost...which is why in JRuby we decided not to make Hash and Array thread-safe by default. There are also a limited set of data structures that make unsynchronized reads concurrent with writes safe. You usually have to have a data structure that's designed to do both safely or they both have to be synchronized. For Hash at least, I think something like a CTrie (concurrent hash array mapped trie) would be a nice choice. It's not O(1) but it's pretty good. ---------------------------------------- Feature #7429: Provide options for core collections to customize behavior https://bugs.ruby-lang.org/issues/7429#change-33868 Author: headius (Charles Nutter) Status: Rejected Priority: Normal Assignee: Category: Target version: 2.0.0 Many folks know that Matz is a fan of having a few classes that handle a wide range of behavior. For this reason, I think we're unlikely to get a set of parallelism-safe collections added to Ruby. I propose an alternative that would allow parallel-executing implementations to offer concurrency-friendly versions without impact to any code. I would like to see a way to pass in an options hash to the .new construction of at least Hash and Array. For example: # Create a hash that is concurrenct-safe, resizes when density is > 3 keys per bucket, # and sets initial bucket count to 60 hsh = Hash.new(concurrent: true, density: 3, size: 60) Similar for Array: ary = Array.new(concurrent: true, size: 100) Options like density and size map directly to current implementation details of Hash and Array that are sometimes not accessible (you can't change the load factor for Hash, for example). Options like concurrent could be noops on MRI but would allow other implementations to provide safe versions of the collections behind the scenes. I know it may be too late for 2.0.0, but we implementers of parallel-executing Rubies feel the pain of thread-unsafe core structures every day. I think the ability to get thread-safe collections in Ruby core would go a long way toward dispelling the myth that Ruby is bad for concurrent application programming.
on 2012-11-25 23:41
Issue #7429 has been updated by matz (Yukihiro Matsumoto). @headius I am afraid it's not going to 2.0, for some reasons: * it's too late to add new classes to 2.0 * and it will take more time to prepare parallel collection implementation for other Ruby (in this case mainly CRuby). * the future CRuby will lean toward non threading way, e.g, Actors. Matz. ---------------------------------------- Feature #7429: Provide options for core collections to customize behavior https://bugs.ruby-lang.org/issues/7429#change-33879 Author: headius (Charles Nutter) Status: Rejected Priority: Normal Assignee: Category: Target version: 2.0.0 Many folks know that Matz is a fan of having a few classes that handle a wide range of behavior. For this reason, I think we're unlikely to get a set of parallelism-safe collections added to Ruby. I propose an alternative that would allow parallel-executing implementations to offer concurrency-friendly versions without impact to any code. I would like to see a way to pass in an options hash to the .new construction of at least Hash and Array. For example: # Create a hash that is concurrenct-safe, resizes when density is > 3 keys per bucket, # and sets initial bucket count to 60 hsh = Hash.new(concurrent: true, density: 3, size: 60) Similar for Array: ary = Array.new(concurrent: true, size: 100) Options like density and size map directly to current implementation details of Hash and Array that are sometimes not accessible (you can't change the load factor for Hash, for example). Options like concurrent could be noops on MRI but would allow other implementations to provide safe versions of the collections behind the scenes. I know it may be too late for 2.0.0, but we implementers of parallel-executing Rubies feel the pain of thread-unsafe core structures every day. I think the ability to get thread-safe collections in Ruby core would go a long way toward dispelling the myth that Ruby is bad for concurrent application programming.
on 2012-11-26 16:28
Issue #7429 has been updated by headius (Charles Nutter). matz (Yukihiro Matsumoto) wrote: > @headius I am afraid it's not going to 2.0, for some reasons: > > * it's too late to add new classes to 2.0 > * and it will take more time to prepare parallel collection implementation for other Ruby (in this case mainly CRuby). In CRuby, with the GIL, you can pretend the existing ones are parallel-safe, can't you? > * the future CRuby will lean toward non threading way, e.g, Actors. If those actors are going to run in parallel, you'll still need to have parallel-safe collections to pass between them...or an explicit mechanism for preventing users from passing mutable state between actors. ---------------------------------------- Feature #7429: Provide options for core collections to customize behavior https://bugs.ruby-lang.org/issues/7429#change-33962 Author: headius (Charles Nutter) Status: Rejected Priority: Normal Assignee: Category: Target version: 2.0.0 Many folks know that Matz is a fan of having a few classes that handle a wide range of behavior. For this reason, I think we're unlikely to get a set of parallelism-safe collections added to Ruby. I propose an alternative that would allow parallel-executing implementations to offer concurrency-friendly versions without impact to any code. I would like to see a way to pass in an options hash to the .new construction of at least Hash and Array. For example: # Create a hash that is concurrenct-safe, resizes when density is > 3 keys per bucket, # and sets initial bucket count to 60 hsh = Hash.new(concurrent: true, density: 3, size: 60) Similar for Array: ary = Array.new(concurrent: true, size: 100) Options like density and size map directly to current implementation details of Hash and Array that are sometimes not accessible (you can't change the load factor for Hash, for example). Options like concurrent could be noops on MRI but would allow other implementations to provide safe versions of the collections behind the scenes. I know it may be too late for 2.0.0, but we implementers of parallel-executing Rubies feel the pain of thread-unsafe core structures every day. I think the ability to get thread-safe collections in Ruby core would go a long way toward dispelling the myth that Ruby is bad for concurrent application programming.
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