libthr and 1:1 threading.

[Jeff Roberson]

On Wed, 2 Apr 2003, Terry Lambert wrote:

> Peter Wemm wrote:
> > No.  It gives the ability for a thread to block on a syscall without
> > stalling the entire system.  Just try using mysqld on a system using libc_r
> > and heavy disk IO.  You can't select() on a read() from disk.  Thats the
> > ultimate reason to do it.  The SMP parallelism is a bonus.
>
> Bug in FreeBSD's NBIO implementation.  A read() that would result
> in page-in needs to queue the request, but return EAGAIN to user
> space to indicate the request cannot be satisfied.  Making select()
> come true for disk I/O after the fault is satisfied is a seperate
> issue.  Probably need to pass the fd all the way down.
>

Please quote the standard that defines this behavior.  This is entirely
counter to everything that I have ever read on the subject.