Date: Fri, 23 Apr 1999 11:08:10 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: Andrew Heybey <ath@niksun.com> Cc: Amancio Hasty <hasty@rah.star-gate.com>, Alex Zepeda <garbanzo@hooked.net>, Chris Piazza <cpiazza@home.net>, freebsd-hackers@FreeBSD.ORG Subject: Re: SMP nerd toy report Message-ID: <199904231808.LAA23991@apollo.backplane.com> References: <199904231658.MAA13662@stiegl.niksun.com>
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: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
Also, buildworld doesn't parallelize as well as it could. There are
so many small programs that one processor is often idle while the
otherone is doing a link. I only get 150% cpu utilization even with the
entire contents of the disk cached.
The 1:15 makes sense verses 50 minutes for my duel-PIII/450. 150% of
50 is 50+25 = 1:15.
-Matt
Matthew Dillon
<dillon@backplane.com>
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