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Date:      Wed, 21 Feb 2001 10:44:42 -0800
From:      Peter Wemm <peter@netplex.com.au>
To:        Robin Cutshaw <robin@XFree86.Org>
Cc:        freebsd-hackers@FreeBSD.ORG
Subject:   Re: Build timings - FreeBSD 4.2 vs. Linux 
Message-ID:  <200102211844.f1LIigf26743@mobile.wemm.org>
In-Reply-To: <20010221090207.A11473@intercore.com> 

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Robin Cutshaw wrote:
> On Mon, Feb 19, 2001 at 12:21:26PM -0800, Peter Wemm wrote:
> > > 
> > > Any ideas as to why it would take almost three times longer to build
> > > on FreeBSD?
> > 
> > This is probably a silly question, but you did recompile the kernel for
> > SMP, right?
> > 
> 
> Actually, I was using the stock GENERIC UP kernel.  I wanted to get a
> baseline.

OK, but this would have been a good thing to tell us to start with. :-)

> > Have you tuned the FreeBSD kernel?  It still ships with a worst-case
> > configuration so that it runs optimally on i386 cpus. :-(  Copy GENERIC
> > to something else and remove all but 'cpu i686', rebuild and install.
> > Also, get rid of 'sl', and 'ppp' from the kernel config as that messes
> > up certain things (interrupt masks).  Ideally, do a proper cleanup and
> > configure it for your specific hardware (ie: remove all the other ethernet
> > drivers, etc).
> > 
> 
> There's a problem here.  I tried to configure an SMP kernel but when it
> booted the fxp0 (Compaq dual eepro100 adapter) got timeout errors and
> wouldn't work.  I went back and did the config/make on the GENERIC
> kernel and booted it.  Same thing.  The stock GENERIC kernel that came
> with the dist works just fine.  Any ideas?
> 
> One other problem I've seen with the Compaq 8500 system.  FreeBSD doesn't
> see the pci adapter on the secondary bus.  I had to move the ethernet
> adapter to the primary bus for it to work.

Perhaps the output of 'pciconf -l' and mptable(8) would be useful.
dmesg also, after a verbose boot (boot -v at the loader).

> > A couple of possibilities..  If you want to compare the two side by side,
> > try mounting the freebsd filesystems in async mode, just like linux does by
> > default.  In particular, make sure you get /tmp, /var/tmp and wherever your
> > build is.
> > 
> 
> OK, I set softupdates on the disk/partition that the build source/target
> is on.  It made no difference in timing.  I then created a memory disk,
> set softupdates on it, and mounted it as /tmp.  AMAZINGLY, the build
> went from 2:50 to 0:40, now much faster than the Linux system.  I'm
> going to do the ram disk thing on Linux and see if it makes a difference.

Are you using the gcc -pipe option for the build? You should.

Second, did you try a softupdates fs mounted on /tmp itself?  I've found
that it makes about the same difference as a ramdisk.  gcc's -pipe largely
makes that irrelevant though.

> Once I figure out the fxp0 problem from above, I'll do a parallel build
> and see what speedups occur.
> 
> Thanks!
> Robin
> -- 
> ----
> Robin Cutshaw         internet: robin@interlabs.com robin@intercore.com
> Internet Labs, Inc.   BellNet:  404-713-4000        robin@XFree86.Org
> XFree86 coreteam/board member
> 
>     "Time is just one damn thing after another" -- PBS/Nova
> ----
> --
> 

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


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