From owner-freebsd-current  Sun Oct 13 17:46:39 1996
Return-Path: owner-current
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.5/8.7.3) id RAA14669
          for current-outgoing; Sun, 13 Oct 1996 17:46:39 -0700 (PDT)
Received: (from jmb@localhost)
          by freefall.freebsd.org (8.7.5/8.7.3) id RAA14663;
          Sun, 13 Oct 1996 17:46:38 -0700 (PDT)
From: "Jonathan M. Bresler" <jmb>
Message-Id: <199610140046.RAA14663@freefall.freebsd.org>
Subject: Re: make -j#
To: peter@spinner.DIALix.COM (Peter Wemm)
Date: Sun, 13 Oct 1996 17:46:37 -0700 (PDT)
Cc: freebsd-current@freebsd.org
In-Reply-To: <53s0at$358$1@haywire.DIALix.COM> from "Peter Wemm" at Oct 14, 96 00:09:01 am
X-Mailer: ELM [version 2.4 PL24]
Content-Type: text
Sender: owner-current@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

Peter Wemm wrote:
> 
> I find that using -pipe is a better overall option for a single-cpu compile.
> When I set in /etc/make.conf:
> CFLAGS= -O -pipe
> COPTFLAGS= -O -pipe
> ..  I find that a simple 'make' is faster than any setting of -j# ..
> 
> This is probably more dependent on the machine in question than anything,
> including things like cache speed, ram speed, disk speed and architecture
> (ie: scsi vs. ide etc).
> 
> I found that the job-complete polling was too chunky though, It seemed that
> make was taking up to half a second to start a new job after the last one
> had finished.  Dropping one of the select timeout parameters from 500000
> usec to 50000 usec made a lot of difference, but it still wasn't quite as
> quick as simply -pipe.
> 
> However, on the smp kernel it certainly is nice! :-)

Peter,
	how much faster is make work on an smp box than on the 
	same box running only one processor?   how much of a boost
	are we getting at this point?

	if i had a multiprocessor box, i would know without asking ;(
jmb