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Date:      Fri, 23 Apr 1999 12:58:44 -0400
From:      Andrew Heybey <ath@niksun.com>
To:        Amancio Hasty <hasty@rah.star-gate.com>
Cc:        Alex Zepeda <garbanzo@hooked.net>, Chris Piazza <cpiazza@home.net>, freebsd-hackers@FreeBSD.ORG
Subject:   Re: SMP nerd toy report 
Message-ID:  <199904231658.MAA13662@stiegl.niksun.com>
In-Reply-To: Your message of Thu, 22 Apr 1999 19:05:05 -0700. <199904230205.TAA00556@rah.star-gate.com> 

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  hasty> I suspect that buildworld is mostly memory bound and not
  hasty> necessarily disk i/o bound unless you have a slow disk.

  >> On Thu, 22 Apr 1999, Chris Piazza wrote:
  >> 
  >> > Understood, I use a single 5400 RPM UDMA Ide disk with the new
  >> ATA drivers - > /usr/obj and /usr/src are on the same partition.
  >> I'm *extremely* pleased with > this system as my P166 took over 4
  >> hours(!).  I'd be interested in seeing what > a difference SCSI
  >> over IDE has in a buildworld.
  >> 
  >> I doubt that the question is SCSI v. IDE.  I know with my P166, I
  >> had horribly cheap "fast" narrow Quantum drives (3.2gb and 640mb)
  >> hooked to an aic7880, and with the PII/450, I've got a 13gb IDE
  >> (UDMA2)drive.  rm -rf of /usr/obj runs much quicker with the UDMA
  >> drive...
  >> 
  >> Sure top-of-the-line SCSI drives probably max out at faster
  >> speeds than the top-of-the-line IDE drives, but I imagine with
  >> softupdates and separate IDE busses, one could create a non
  >> diskbound PII (under buildworld conditions).
  >> 
  >> - alex
  >> 
  >> 
  >> 
  >> To Unsubscribe: send mail to majordomo@FreeBSD.org with
  >> "unsubscribe freebsd-hackers" in the body of the message

Well, I tried a couple of "make buildworld" on a single-processor P-II 
450, 256MB ram, /usr/src and /usr/obj on separate 10000RPM IBM scsi
disks, softupdates.  This is a build with an empty /usr/obj.  No
changes to /etc/make.conf except CFLAGS="-O -pipe".  The OS
is 3.1-STABLE as of 03/21/1999.

Took about 1:15 (tried one with -j4 and one with -j8--no difference).
This is about the same as my dual celeron 300A (at 300MHz/66MHz FSB)
with a *single* IDE drive and 64MB of memory.  I expected it to be
faster presuming that the build is IO or memory bound (faster disks
(or at least two spindles) and faster memory).  This system is
building 3.1-RELEASE if that makes a difference.

It is noticably slower than my dual celery at 450 MHz/100MHz FSB
(about 0:55), which seems to say that CPU does have something to do
with it.

So what conclusions can I draw?  Softupdates schedules the disk so
well as to negate the effect of an extra spindle?  buildworld is at
least partially CPU bound?  3.1-RELEASE takes less to build than
3.1-STABLE (as of 03/21/1999)?  (I didn't think there were any major
new chunks added but I could be wrong.)

andrew











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