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Date: Fri, 2 Mar 2007 14:08:21 +0300
From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
To: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Machek <pavel@ucw.cz>, Theodore Tso <tytso@mit.edu>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Ulrich Drepper <drepper@redhat.com>, linux-kernel@vger.kernel.org,
       Arjan van de Ven <arjan@infradead.org>,
       Christoph Hellwig <hch@infradead.org>, Andrew Morton <akpm@zip.com.au>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, Zach Brown <zach.brown@oracle.com>,
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       Davide Libenzi <davidel@xmailserver.org>,
       Jens Axboe <jens.axboe@oracle.com>,
       Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3
Message-ID: <20070302110820.GA25908@2ka.mipt.ru>
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On Fri, Mar 02, 2007 at 11:56:18AM +0100, Ingo Molnar (mingo@elte.hu) wrote:
> 
> * Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> 
> > Even if kevent has the same speed, it still allows to handle _any_ 
> > kind of events without any major surgery - a very tiny structure of 
> > lock and list head and you can process your own kernel event in 
> > userspace with timers, signals, io events, private userspace events 
> > and others without races and invention of differnet hacks for 
> > different types - _this_ is main point.
> 
> did it ever occur to you to ... extend epoll? To speed it up? To add a 
> new wait syscall to it? Instead of introducing a whole new parallel 
> framework?

Yes, I thought about its extension more than a year ago before started 
kevent, but epoll() is absolutely based on file structure and its 
file_operations with poll methodt, so it is quite impossible to work 
with sockets to implement network AIO. Eventually it had gathered a lot 
of other systems - do we really want to have per process signalfs, timerfs 
and so on - each simple structure must be bound to a file, which becomes 
too cost.

> 	Ingo

-- 
	Evgeniy Polyakov