[GSoC Proposal draft] High-Level Networking

[Jose Armando Garcia]

Mind you that Async IO is different from Non-blocking IO (which is
what most literature talks about). I am not an expert with Async IO
but it has serious limitations in Windows like the kernel thread that
starts the IO must complete it. Not very familiar with the state of
AIO in Linux.

Good luck.

On Fri, Apr 1, 2011 at 10:51 PM, Jose Armando Garcia <jsancio at gmail.com> wrote:
> That all sounds good. I would add Flash to your investigation:
> http://www.cs.princeton.edu/~vivek/flash/. There is a must read
> research paper for any distributed system person at:
> http://www.cs.princeton.edu/~vivek/flash_usenix_99/
>
> On Fri, Apr 1, 2011 at 8:17 PM, Max Klyga <max.klyga at gmail.com> wrote:
>> Since my proposal theme shifted a little towards asyncronicity, I've been
>> eagerly consuming information that might help me with this.
>>
>> I would be glad to know if I am moving in to the right direction. Comments
>> are welcome.
>>
>> So far, here is the status report:
>> I looked at approaches to asyncronicity in Ruby's NeverBlock, C#, Qt,
>> Boost.ASIO
>>
>> NeverBlock uses Fibers for managing asyncronous operations. One fiber acts
>> as a scheduler, polling async operations for complition and resuming other
>> fibers as needed.
>>
>> C# uses several approaches to asyn operations. There are three common
>> patterns now:
>> - Split async functon in two (BeginFoo, EndFoo). Begin... function returns
>> IAsyncResult object and shedules operation in process-default thread pool.
>> End... function takes IAsyncResult object that we got earlier and, if
>> operation was complited, returns computation results or blocks until the
>> operation is completed. All exceptions thrown in asyncronous operation are
>> stored and rethrown when user calls End... function.
>>  Any function can be called asyncronously using built in wrapper.
>> - Some classes provide the following interface for time consuming
>> operations:
>>   class Foo {
>>       bar(...); // blocking operation
>>       asyncBar(...); // asyncronous operation
>>
>>       cancelAsync();
>>
>>       barCompleted;
>>
>>       barResult;
>>   }
>> - Task-based asyncronicity, similar to std.parallelism. Async operations
>> (BeginFoo, EndFoo) can be wrapped as a task and scheduled to be executed on
>> user controlled task pools.
>>
>> Qt uses it's signal/slot mechanism for asyncronous operations. It's somewhat
>> similar to C# events, or arrays of D delegates.
>>
>> Boost.ASIO is based on callbacks/delegates. It's implementation is based on
>> proactor design pattern and doesn't use Fibers or Threads.
>>
>>
>> I've also spent some time digging up info on event-based servers.
>> This is my to-read list on this weekend:
>>        [1] Ous96 John Ousterhout. Why threads are a bad idea (for most
>> purposes). In USENIX Technical Conference (Invited Talk), Austin, TX,
>> January 1996.
>>        [2] Rob von Behren, Jeremy Condit, and Eric Brewer. 2003. Why events
>> are a bad idea (for high-concurrency servers). In Proceedings of the 9th
>> conference on Hot Topics in Operating Systems - Volume 9 (HOTOS'03), Vol. 9.
>> USENIX Association, Berkeley, CA, USA, 4-4.
>>        [3] Atul Adya , Jon Howell , Marvin Theimer , William J. Bolosky ,
>> John R. Douceur, Cooperative Task Management Without Manual Stack
>> Management, Proceedings of the General Track: 2002 USENIX Annual Technical
>> Conference, p.289-302, June 10-15, 2002 (related presentation:
>> http://www.cs.nyu.edu/rgrimm/teaching/fa03-web/091603.pdf)
>>        [4] http://www.kegel.com/c10k.html
>>        [5] http://tomasp.net/blog/csharp-fsharp-async-intro.aspx (I should
>> look at how F# handles asyncronicity)
>>
>>
>