libkse -> libpthread

[Daniel Eischen]

On Tue, 22 Apr 2003, Igor Sysoev wrote:

> On Mon, 21 Apr 2003, Daniel Eischen wrote:
> > Libpthread can be made to behave the same as libthr just
> > by forcing every thread to be scope system.  Currently,
> > the implementation for scope system threads does have
> > a small amount of overhead in that they still get upcalls
> > after the thread blocks in the kernel (in this case
> > the KSE just reenters the kernel with kse_release()
> > and waits for the thread to become unblocked).  These
> > KSEs also require a small stack separate from the
> > thread's stack.  The code is in place (in the UTS) to
> > not require a separate stack and not get any upcalls
> > for these threads, but we just need a bit more
> > kernel work to optimize this overhead away.
> 
> But why is not it implemented via setting kse_mailbox.km_curthread to NULL ?
> As I understand it's way to disable upcalls when UTS is preempted
> by the kernel (the time slice ended, the page in operation, etc.)
> i.e. UTS should always run as 1:1 thread.
> Had it been changed ?  How is UTS protected now ?

We can't use this method yet for 1:1 because we don't
have a way to redirect a signal to a thread running
like this.  We need kse_thr_interrupt() to have a signal
argument and for the kernel to install the signal frame
on the stack of the target thread (or keep it pending
on the thread if masked).

-- 
Dan Eischen