From owner-cvs-src@FreeBSD.ORG  Tue Apr  6 12:19:04 2004
Return-Path: <owner-cvs-src@FreeBSD.ORG>
Delivered-To: cvs-src@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id 75B4016A4CE; Tue,  6 Apr 2004 12:19:04 -0700 (PDT)
Received: from repoman.freebsd.org (repoman.freebsd.org [216.136.204.115])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 6F6D243D3F; Tue,  6 Apr 2004 12:19:04 -0700 (PDT)
	(envelope-from jhb@FreeBSD.org)
Received: from repoman.freebsd.org (localhost [127.0.0.1])
	by repoman.freebsd.org (8.12.10/8.12.10) with ESMTP id i36JHlGe036984;
	Tue, 6 Apr 2004 12:17:47 -0700 (PDT)
	(envelope-from jhb@repoman.freebsd.org)
Received: (from jhb@localhost)
	by repoman.freebsd.org (8.12.10/8.12.10/Submit) id i36JHlTU036983;
	Tue, 6 Apr 2004 12:17:47 -0700 (PDT)
	(envelope-from jhb)
Message-Id: <200404061917.i36JHlTU036983@repoman.freebsd.org>
From: John Baldwin <jhb@FreeBSD.org>
Date: Tue, 6 Apr 2004 12:17:47 -0700 (PDT)
To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org,
	cvs-all@FreeBSD.org
X-FreeBSD-CVS-Branch: HEAD
Subject: cvs commit: src/sys/kern kern_condvar.c src/sys/sys condvar.h
X-BeenThere: cvs-src@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: CVS commit messages for the src tree <cvs-src.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src>,
	<mailto:cvs-src-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/cvs-src>
List-Post: <mailto:cvs-src@freebsd.org>
List-Help: <mailto:cvs-src-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src>,
	<mailto:cvs-src-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 06 Apr 2004 19:19:04 -0000

jhb         2004/04/06 12:17:46 PDT

  FreeBSD src repository

  Modified files:
    sys/kern             kern_condvar.c 
    sys/sys              condvar.h 
  Log:
  Associate a simple count of waiters with each condition variable.  The
  count is protected by the mutex that protects the condition, so the count
  does not require any extra locking or atomic operations.  It serves as an
  optimization to avoid calling into the sleepqueue code at all if there are
  no waiters.
  
  Note that the count can get temporarily out of sync when threads sleeping
  on a condition variable time out or are aborted.  However, it doesn't hurt
  to call the sleepqueue code for either a signal or a broadcast when there
  are no waiters, and the count is never out of sync in the opposite
  direction unless we have more than INT_MAX sleeping threads.
  
  Revision  Changes    Path
  1.48      +13 -2     src/sys/kern/kern_condvar.c
  1.11      +5 -1      src/sys/sys/condvar.h