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To: Terry Lambert <tlambert2@mindspring.com>
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Date: Wed, 02 Apr 2003 15:40:16 -0800
From: Peter Wemm <peter@wemm.org>
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cc: csujun@21cn.com
cc: current@FreeBSD.org
Subject: Re: libthr and 1:1 threading. 
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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.

Umm Terry.. we have zero infrastructure to support this.

Cheers,
-Peter
--
Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5