Subject: Re: Importing kqueue's from FreeBSD...
To: Jonathan Lemon <>
From: Jason R Thorpe <>
List: tech-kern
Date: 03/15/2001 16:02:05
On Thu, Mar 15, 2001 at 03:40:49PM -0600, Jonathan Lemon wrote:

 > I'll admit the performance section of the paper is sadly lacking; I'm
 > working on that at the moment.
 > If there is no knote attached to the structure being monitored, then
 > the overhead is just a single if() statement.  Otherwise, the overhead
 > is roughly O(N), where N is the number of knotes attached to the structure. 

Yah, seems to me roughly like the overhead of selwakeup(), except not
nearly as pathological when multiple things are looking at a particular
e.g. socket.

I have no beef with kqueue other than the lack of really really really
generic event type stuff.

For example, luke said EVFILT_DEVICE -- ok, so, the problem is that you
get notified that an EVFILT_DEVICE event occurred... was it an insert or
a removal?  How do you tell?  Unless I missed something, there doesn't
seem to be any way of passing down ancillary data with the event.

        -- Jason R. Thorpe <>