Date: Sun, 25 Jun 2000 20:07:44 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Julian Elischer <julian@elischer.org> Cc: Jason Evans <jasone@canonware.com>, smp@FreeBSD.ORG Subject: Re: SMP meeting summary Message-ID: <13298.961956464@critter.freebsd.dk> In-Reply-To: Your message of "Sun, 25 Jun 2000 10:41:57 PDT." <39564465.794BDF32@elischer.org>
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In message <39564465.794BDF32@elischer.org>, Julian Elischer writes: >Jason Evans wrote: > >> - Netgraph poses locking performance problems, since locks have to be >> released at multiple potential transfer points, regardless of whether >> Netgraph is in use. This problem also exists with System V STREAMS. >> During the meeting we didn't come to a clear consensus on how much of >> a problem this really is. >> > > >I think this is a mis-stated issue. >There is no REQUIREMENT that locks be released >or held at every transfer between modules. > >While it is the case that some modules may require >locking operations, it cannot be said that there is a 1:1 >correspondence between locks and modules. >A packet could wuite easily travel thought quite >a number of modules without any additional locking work. >Many modules would have no resources worth protecting.. >(at least in the common case) The "cisco" module being a very good example. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD coreteam member | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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