Date: Tue, 6 Mar 2001 12:11:37 -0700 (MST) From: Nate Williams <nate@yogotech.com> To: Daniel Eischen <eischen@vigrid.com> Cc: Nate Williams <nate@yogotech.com>, java@FreeBSD.ORG Subject: Re: Java and libc/libpthread Message-ID: <15013.13929.646718.255566@nomad.yogotech.com> In-Reply-To: <Pine.SUN.3.91.1010306134458.26948A-100000@pcnet1.pcnet.com> References: <15013.11891.57267.160163@nomad.yogotech.com> <Pine.SUN.3.91.1010306134458.26948A-100000@pcnet1.pcnet.com>
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> > > > > I'm currently working on an NxN libpthread implementation as
> > > > > an interim solution until we get KSEs. The goal is to get
> > > > > this done before 5.0.
> > > >
> > > > How is this different from the current implementation?
> > >
> > > File descriptors will not be made non-blocking like they are
> > > currently in libc_r. When a thread blocks on I/O, it _really_
> > > blocks -- no other threads will be scheduled within that
> > > [rfork_thread'd/cloned] process.
> >
> > So, reversing the logic ('not be made non-blocking'), file descriptors
> > will be made blocking?
>
> Right, err, well, they're whatever the application decides to set
> them to.
>
> > This doesn't seem like progress, but I may not
> > understand the implications.
>
> Some folks find that our libc_r doesn't scale very well for their
> applications and that linuxthreads (under Linux) perform much,
> much, better.
For file-descriptors that *must* block (ie; reading from stdin, or other
non-deterministic desciptors), LinuxThreads scales much better.
> libc_r will still be around for folks to use; this will be a separate
> library (libpthread).
Gotcha.
> Solaris 8 provides /usr/lib/lwp/libpthread that provides (by
> default) a library tailored for NxN. They (Sun) found that it
> performed better for Java threads.
Java doesn't give the author any control over the thread
creation/removal or scope, so the overhead of MxN model is useless for
Java.
> > So, you're going to create a system similar to Linux-threads, but with a
> > more BSD-like license?
>
> Right.
Wonderful!
Nate
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