Message-Id: <200502201036.j1KAagE04722@blake.inputplus.co.uk>
To: Andrea Arcangeli <andrea@suse.de>, linux-kernel@vger.kernel.org,
       darcs-users@darcs.net
Subject: Re: [darcs-users] Re: [BK] upgrade will be needed 
In-Reply-To: <20050219171457.GA20285@abridgegame.org> 
Date: Sun, 20 Feb 2005 10:36:42 +0000
From: Ralph Corderoy <ralph@inputplus.co.uk>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1489
Lines: 37


Hi,

David Roundy, creator of darcs, wrote:
> On Sat, Feb 19, 2005 at 05:42:13PM +0100, Andrea Arcangeli wrote:
> > I read in the webpage of the darcs kernel repository that they had
> > to add RAM serveral times to avoid running out of memory. They
> > needed more than 1G IIRC, and that was enough for me to lose
> > interest into it.  You're right I blamed the functional approach and
> > so I felt it was going to be a mess to fix the ram utilization, but
> > as someone else pointed out, perhaps it's darcs to blame and not
> > haskell. I don't know.
> 
> Darcs' RAM use has indeed already improved somewhat... I'm not exactly
> sure how much.  I'm not quite sure how to measure peak virtual memory
> usage, and most of the time darcs' memory use while doing the linux
> kernel conversion is under a couple of hundred megabytes.

Wouldn't calling sbrk(0) help?  I don't know if the Haskell run-time
ever shrinks the data segment, if not, it could just be called at the
end.  Or a `strace -e trace=brk darcs ...' might do.  But I guess darcs
has other VM usage that doesn't show in this figure?  Does /proc/$$/maps
if running under Linux help?

A consistent way to measure would be handy for observing changes over
time.

Cheers,


Ralph.

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