Re: [PATCH 2 of 4] Introduce i386 fibril scheduling

From: Linus Torvalds
Date: Tue Feb 06 2007 - 16:29:32 EST




On Tue, 6 Feb 2007, David Miller wrote:
>
> I really think that Evgeniy's kevent is a good event notification
> mechanism for anything, including AIO.
>
> Events are events, applications want a centralized way to receive and
> process them.

Don't be silly. AIO isn't an event. AIO is an *action*.

The event part is hopefully something that doesn't even *happen*.

Why do people ignore this? Look at a web server: I can pretty much
guarantee that 99% of all filesystem accesses are cached, and doing them
as "events" would be a total and utter waste of time.

You want to do them synchronously, as fast as possible, and you do NOT
want to see them as any kind of asynchronous events.

Yeah, in 1% of all cases it will block, and you'll want to wait for them.
Maybe the kevent queue works then, but if it needs any more setup than the
nonblocking case, that's a big no.

Linus
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