Re: [boost] [afio] Formal review of Boost.AFIO

Subject: Re: [boost] [afio] Formal review of Boost.AFIO
From: Thomas Heller (thom.heller_at_[hidden])
Date: 2015-08-31 10:50:26

On 08/31/2015 04:25 PM, Niall Douglas wrote:
> On 31 Aug 2015 at 1:38, Thomas Heller wrote:
> 
>> On 08/30/2015 10:06 PM, Niall Douglas wrote:
>>> 7. future.wait() very rarely blocks in your use scenario i.e. most if
>>> not nearly all the time the future is ready. If you are blocking, the
>>> cost of any thread sleep will always dwarf the cost of any future.
>>
>> Is this really an assumption that holds when dealing with operations 
>> that do file I/O? I have a hard time believing this is the general case.
> 
> Imagine the copying of a 10Mb file in 1Mb segments. You would create 
> a minimum of 11 future-promise pairs, and only wait on the very last 
> one.
> 
> My own benchmarking here suggested that (much) lighter weight futures 
> would let me implement a much more efficient ASIO reactor than ASIO's 
> and push all potential blocking to outside AFIO, perhaps right down 
> to the final end user layer. Perhaps thousands of future-promise 
> pairs might be created, continued from and destroyed between actual 
> thread blocks. This is why I believe - currently without real world 
> proof - this ought to be a big win.

How does this answer my question?

> 
> Niall
> 
> 
> 
> 
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-- 
Thomas Heller
Friedrich-Alexander-Universität Erlangen-Nürnberg
Department Informatik - Lehrstuhl Rechnerarchitektur
Martensstr. 3
91058 Erlangen
Tel.: [phone]
Fax:  [phone]
Email: thomas.heller_at_[hidden]