From owner-freebsd-arch@FreeBSD.ORG  Mon Mar  6 19:39:13 2006
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Date: Mon, 6 Mar 2006 11:39:12 -0800 (PST)
From: Matthew Dillon <dillon@apollo.backplane.com>
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To: John Baldwin <jhb@freebsd.org>
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Cc: dima <_pppp@mail.ru>, arch@freebsd.org,
	Poul-Henning Kamp <phk@phk.freebsd.dk>,
	Robert Watson <rwatson@freebsd.org>, freebsd-arch@freebsd.org
Subject: Re: wakeup idea...
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X-List-Received-Date: Mon, 06 Mar 2006 19:39:14 -0000

    I've tried many variations of the idea of passing a real structure
    to sleep/wakeup and eventually gave up on trying to change the API.
    It is just too useful to be able to pass an arbitrary 'id' as a the
    rendezvous point.

    But, what I *did* do was implement scheduling primitives that 
    sleep/wakeup uses to do the actual descheduling and rescheduling of
    the kernel thread, and there are a number of mechanisms in DragonFly
    which use those primitives directly rather then using sleep/wakeup.
    In particular, the interrupt thread procedure, softclock thread,
    and DragonFly's LWKT messaging subsystem (e.g. lwkt_default_waitport()).

    So what I would recommend is that the sleep/wakeup API *NOT* be changed,
    but instead you simplify the lower level APIs that sleep/wakeup uses
    to the point where other high performance APIs in the system, such as
    lockmgr, can call them directly without making a mess.

						-Matt