Subject: Re: So I'll bite. M:N w/o SA - how?
To: None <>
From: Bucky Katz <>
List: tech-kern
Date: 02/22/2007 10:42:51
Joerg Sonnenberger <> writes:

> On Wed, Feb 21, 2007 at 11:40:24AM -0800, Bucky Katz wrote:
>> Bill Studenmund <> writes:
>> > When a thread blocks in the kernel, you'd like to run something
>> > else on that thread, no?
>> Yes. This is why I don't believe you can accomplish this entirely
>> in userland.
> That's the point where I disagree. I do not think it is necessary to do
> that or even helpful. Let blocking events block the lwp.  When you took
> the time for a trap, the context switching overhead is reasonably small.

In the uniprocessor case M:N degenerates to N:1, in practice. If I let
the 1 lwp block, how do I get any of the other threads scheduled?