Date:	Thu, 2 Mar 2000 11:18:36 +0200 (IST)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender:	eliz AT is
To:	Kalum Somaratna aka Grendel <kalum AT crosswinds DOT net>
cc:	djgpp AT delorie DOT com
Subject:	Re: rhide compile..
In-Reply-To:	<Pine.LNX.4.10.10003011856320.679-100000@darkstar.grendel.net>
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On Wed, 1 Mar 2000, Kalum Somaratna aka Grendel wrote:

> > SmartDrv flushes its buffers when a program exits, so it is slower
> > than a RAM disk.  
> 
> This is the default behaviour of smatrdrv and is there for people who are
> afraid that they might loose data because of write caching etc.
> But if you add the /N option IIRC this will tell smartdrv not to flush the
> write cache when the program exits. 

See my followups, they explain why /N is not what you think it is.

> > > And there will be more efficient memory usage as there is no need to
> > > allocate memory as in a ramdisk for the whole tool chain, for how many of
> > > the tools do we actually use?
> > 
> > If you have enough memory installed, this is not an issue.
> 
> Actually how much should "enough" be?

If you have 64MB or more installed, I don't think you should have
problems with having a large SmartDrv cache and a fairly large RAM
disk.

> GCC itself hogs up a large amount of
> memory and allocationg too much memory for a ramdisk will be
> counterproductive as GCC will start paging to the hard disk.

I have a 10MB cache and a 4MB RAM disk on a 64MB machine, and I have
yet to see GCC paging, even though I mostly invoke it from Emacs,
which itself gobbles upwards of 10MB of memory on a bright day.

Of course, one can come up with a source which would cause GCC to page
with *any* amount of memory.  (Just a few days ago someone reported on
the GCC mailing list that a certain code line caused GCC to allocate
500MB of memory.)  The question is, how frequently do these
pathological cases happen to warrant changes in system configuration.
Punishing 99.99% of compiles because of the naughty 0.01% is not wise,
IMHO.

> FWIW I find that a 8mb smartdrv with write caching enabled and the /N
> switch works marvels and is far easier to setup than a RAMDISK.

Try adding a 2MB RAM disk on top of that, point TMPDIR to it, and see
the effect.

Setup problem?  What setup problems?  There are no setup problems ;-).

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