Date: Tue, 04 Jun 1996 22:19:45 -0700 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@HeadCandy.com> To: Terry Lambert <terry@lambert.org> Cc: smp@freebsd.org Subject: Re: Unix/NT synchronization model (was: SMP progress?) Message-ID: <199606050519.WAA25284@MindBender.HeadCandy.com> In-Reply-To: Your message of Tue, 04 Jun 96 17:10:34 -0700. <199606050010.RAA27773@phaeton.artisoft.com>
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>> Early SMP versions of just about every SMP Unix OS I know of started out
>> being a single lock and became fine-grained in subsequant versions (in many
>> cases before the code was officially released).
>Yes. The simplest method of increasing granularity is to tier the
>locks as global mutexes (not fix that yet), and then "push down" the
>locks through th trap code into the system call layer.
What exactly do you mean by "push down the locks through the trap
code"?
>At that point, you are free to add locks to structures accessed as a
>result of an interrupt or exception (the only two ways, other than the
>trap, to get into the kernel), and then you can multithread the whole
>damn thing, one subsystem at a time.
Kind of how I had envisioned it...
>You break the trap lock into inferior locks, one per subsystem (ie: VFS),
>and then break that lock further to push down a call at a time in the
>given subsystem.
What exactly do you mean by breaking the lock down? Are you saying to
have a general lock cover a broad range of kernel access, then make a
more specific lock for a subset of that range and remove that subset
from the broader lock?
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Michael L. VanLoon michaelv@HeadCandy.com
--< Free your mind and your machine -- NetBSD free un*x >--
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