Date: Sun, 12 Dec 1999 16:48:41 -0500 From: "Daniel M. Eischen" <eischen@vigrid.com> To: Julian Elischer <julian@whistle.com> Cc: Arun Sharma <adsharma@sharmas.dhs.org>, arch@freebsd.org Subject: Re: Recent face to face threads talks. Message-ID: <38541839.2C2BDF2F@vigrid.com> References: <Pine.BSF.4.10.9912121101200.26823-100000@current1.whistle.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Julian Elischer wrote:
> Yes we agreed that "kernel threads' would hopefully belong to a "Q" that
> was hung off proc0 and which would have 'realtime' scheduling
> characteristics. This brings up something that was mentionned but that I
> dont remember an explicit agreement to, though I think averyone agreed..
>
> There is a syscall that jumpstarts the threading support. It supplies the
> kernel with the information needed to do upcalls. Until this call is made
> there can be no upcalls and the process is effectively unthreaded. This
> call is repeated for each 'thread class', and in fact we call it foreach
each 'Q'?
> CPU as well. each time you call it you define another 'virtual cpu', and
> supply it with upcal information. Each virtual CPU has therefore a
> different UTS instantiation (read stack) (they can be small). It can
> therefore be stated that each "Q" structure effectively corresponds to an
> UTS instance.
There will probably have to be more than "UTS instantion" (UTS stack).
During a preemption notification, the UTS might have to resume a preempted
thread before dealing with stuff on the UTS stack. Therefore the
kernel doesn't know if the UTS stack is still in use. I think it
better to have the UTS provide a set of stacks to use for upcall
notifications as described in the SA papers. These can be cached and
returned to the kernel in bulk.
Dan Eischen
eischen@vigrid.com
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-arch" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?38541839.2C2BDF2F>