Re: [Boost-users] [ASIO] directory monitor ASIO extension

Subject: Re: [Boost-users] [ASIO] directory monitor ASIO extension
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2014-08-05 20:54:20

On 6 Aug 2014 at 0:17, Bjorn Reese wrote:

> On 08/05/2014 03:36 PM, Szymon Gatner wrote:
> 
> > I am going through code of directory monitor ASIO extension by Boris
> 
> You may also be interested in AFIO (F for file.) It has an experimental
> directory monitor living in some branch whose name I do not know.
> 
>    https://github.com/BoostGSoC/boost.afio.git

Ah yes. The directory monitor isn't ready for production use. By 
production use I mean:

* Can cope with 1m entry directories easily as the rest of AFIO can.

* Can handle 50,000 entries changing every second in a 1m entry 
directory without losing change deltas and without racing on 
individual stats on a 2Ghz single core, with approximate linear 
scaling with additional cores i.e. four cores can monitor four 1m 
entry directories seeing 5% change.

* Works as expected on remotely mounted filing systems like NFS.

* Uses native OS features to avoid polling when possible.

* Works reliably on Microsoft Windows (hard), Linux (slightly 
easier), BSD and OS X (easiest by far of the lot).

Paul Kirth presented on this at C++ Now 2014. It is a surprisingly 
tough engineering problem, and requires a design approaching ideal 
for it to work at all.

tl;dr; it'll be a while longer. Paul is still kicking at it.

Niall

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