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Date: Tue, 19 Sep 2006 16:11:12 +0400 (MSD)
From: Dmitry Morozovsky <marck@rinet.ru>
To: freebsd-hackers@freebsd.org, danny@cs.huji.ac.il
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Cc: 
Subject: Re: numbers don't lie ...
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On Thu, 14 Sep 2006, Oliver Fromme wrote:

OF> Because buildworld is I/O-bound on systems with sufficiently
OF> fast processors.
OF> 
OF> Try putting the contents of /usr/src into a RAM disk and
OF> repeat the benchmark.  The numbers might look a little
OF> different then.  Of course, you should have sufficient RAM
OF> in the machines -- If they're going to swap to the disks,
OF> your benchmark won't be happy.
OF> 
OF> I think putting /usr/obj onto a RAM disk is _not_ necessary
OF> because of soft-updates, so the processes shouldn't block
OF> on writes.

My experiments show that if you have enough memory to host radmdrive for 
/usr/src you'd better leave it for caching - there were no statistically
meaningful performance difference, at least on machines with 1G+ RAM.

Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru ***
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