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Date:      Tue, 13 Apr 2010 15:35:51 +1000
From:      Andrew Snow <als@modulus.org>
To:        Maho NAKATA <chat95@mac.com>
Cc:        freebsd-stable@freebsd.org
Subject:   Re: Only 70% of theoretical peak performance on FreeBSD 8/amd64, Corei7 920
Message-ID:  <4BC402B7.5000400@modulus.org>
In-Reply-To: <h2yca3526251004122230l909bc93ey916d7fe0dd24fd33@mail.gmail.com>
References:  <20100412.131213.4959786962516027.chat95@mac.com> <h2yca3526251004122230l909bc93ey916d7fe0dd24fd33@mail.gmail.com>

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The statements about the scheduler flipping between cores is also 
somewhat false, ULE does the right thing now for long-running 
computational threads.

Furthermore, I can't see how a Gflops benchmark which fits in the CPU 
cache has anything to do with the memory architecture of the operating 
system.

I assume to reach these results the benchmark was multi-threaded, and so 
I think I'd start by looking at the scheduler.

Before that I'd probably look at the libraries, how they were compiled, 
differences in the compiler etc.

- Andrew




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