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Date: Tue, 20 Apr 2004 11:53:22 +0300
From: Rumen Telbizov <altares@e-card.bg>
To: Kris Kennaway <kris@obsecurity.org>
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cc: stable@freebsd.org
Subject: Re: HTT and SMP question
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> > Would you please point out some cases when HTT with machdep.hlt_logical_cpus=0
> > causes worse performance than machdep.hlt_logical_cpus=1?
> > I am using an HTT Xeon since recently and in my tests it showed that
> > machdep.hlt_logical_cpus=0 is better!
> > A simple ubench (spawning 2 processes) gives better results in 0 mode!
> 
> My parallel package builds are slower on build machines with HTT.
> It's not a magic bullet.
> 
> Kris

Hmm ... interesting. My simple/stupid synthetic tests
showed just the opposite. Anyway. Unfortunatelly I didn't
try to buildworld/kernel with -j2 (say). Shame on me!

Would you point to a case where machdep.hlt_logical_cpus=0 does
show better performance results? httpd ?

Is it not that exactly _parallel processing_ should be faster with HTT
than whithout ?

Thank you for your reply.

Rumen Telbizov