From owner-freebsd-hackers  Mon May 11 20:36:17 1998
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Received: (from majordom@localhost)
          by hub.freebsd.org (8.8.8/8.8.8) id UAA20479
          for freebsd-hackers-outgoing; Mon, 11 May 1998 20:36:17 -0700 (PDT)
          (envelope-from owner-freebsd-hackers@FreeBSD.ORG)
Received: from flamingo.McKusick.COM (root@flamingo.mckusick.com [205.217.47.105])
          by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id UAA20353;
          Mon, 11 May 1998 20:35:59 -0700 (PDT)
          (envelope-from mckusick@flamingo.McKusick.COM)
Received: from flamingo.McKusick.COM (mckusick@localhost [127.0.0.1])
	by flamingo.McKusick.COM (8.8.5/8.8.5) with ESMTP id SAA29353;
	Mon, 11 May 1998 18:58:57 -0700 (PDT)
Message-Id: <199805120158.SAA29353@flamingo.McKusick.COM>
To: Jason Thorpe <thorpej@nas.nasa.gov>
Subject: Re: more queue.h brokenness 
cc: Julian Assange <proff@iq.org>, "Justin T. Gibbs" <gibbs@plutotech.com>,
        gibbs@FreeBSD.ORG, hackers@FreeBSD.ORG, dyson@FreeBSD.ORG,
        mrg@eterna.com.au
In-reply-to: Your message of "Mon, 11 May 1998 18:37:29 PDT."
             <199805120137.SAA02585@lestat.nas.nasa.gov> 
Date: Mon, 11 May 1998 18:58:50 -0700
From: Kirk McKusick <mckusick@McKusick.COM>
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

TAILQ macros run about 20% faster than CIRCLEQ macros on typical
insertion, deletion, and lookup ratios due to fewer tests, and
testing terminaion against NULL rather than a computed value.
CIRCLEQ's win when your are predominently traversing them in the
reverse direction. Frankly, if I had figured out how to traverse
TAILQ's backwards when I wrote the queue macros, I would not have
put CIRCLEQ's into the macro set at all.

	Kirk McKusick

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message