Subject: Re: upcalls?
To: Noriyuki Soda <>
From: Jason Thorpe <>
List: tech-kern
Date: 12/09/1999 10:05:47
On Fri, 10 Dec 1999 02:55:35 +0900 (JST) 
 Noriyuki Soda <> wrote:

 > 	Scheduler Activation - Scheduler activations provide
 > 	additional kernel-scheduling support for multithreaded
 > 	applications.
 > Don't you believe Sun's white paper about Solaris 2.6?

I'd be willing to wager that what they actually did was enhance
their existing LWP-based thread package with the upcall mechanism
from Scheduler Activations.

I'd like to point out that Scheduler Activations is really another name
for LWP.  I.e. in the original SA paper, they describe "Scheduler Activations"
as an alternate scheduling primitive... and the original SA wasn't done on
UNIX -- it was done on a research OS called Topaz which already provided
a similar mechanism to LWPs.

I think we would be well-served to convert our kernel to use LWPs as
the scheduling primitive (like Solaris), and adding the upcall mechanism
documented in the SA paper.

This would also be a win for our Solaris emulation.  And it might not
actually be that hard to do.

        -- Jason R. Thorpe <>