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Date:      Tue, 4 Nov 1997 20:19:09 -0500 (EST)
From:      "John S. Dyson" <toor@dyson.iquest.net>
To:        garbanzo@hooked.net (Alex)
Cc:        toor@dyson.iquest.net, freebsd-current@FreeBSD.ORG
Subject:   Re: More on fast make world...
Message-ID:  <199711050119.UAA13860@dyson.iquest.net>
In-Reply-To: <Pine.BSF.3.96.971104171512.3158B-100000@zippy.dyn.ml.org> from Alex at "Nov 4, 97 05:16:17 pm"

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Alex said:
> 
> 
> On Tue, 4 Nov 1997, John S. Dyson wrote:
> 
> > > Silly question:  How do I do that?  Last I tried I ended in a panic...
> > > How large? Where to mount?  /tmp or /var/tmp?  I foreget ...
> > > 
> > > Without these improvements, we are at 102 minutes end-to-end.  Let's go for
> > > sub-hour make world!
> > > 
> > 
> > This is my fstab entry.  You'll also have to add the MFS option to the kernel.
> > The -s param should be smaller than your amount of swap.  To add -pipe, just
> > edit your /etc/make.conf file and add -pipe to your CFLAGS entry.
> > 
> > swap			/tmp		mfs	rw,-s=210000,-b=16384,-f=2048 0 0
> 
> Ok, this is probably a silly question, but here it goes.  What exactly is
> MFS?  Is it akin to a ramdisk?  Or is it just swap space that's emulating
> a drive slice?  If it's realy out of swap space, how would that actually
> improve performance?
> 
Think of it as a ramdisk, that is backed by swap if it is needed.  It
"soft-fails".  Our implementation isn't as efficient as it could be,
but there is almost no reason that a swap-backed ramdisk should be much
slower than a non-swap-backed ramdisk. 

-- 
John
dyson@freebsd.org
jdyson@nc.com



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