Date: Tue, 23 Dec 2008 10:05:08 -0500 From: Mike Tancsa <mike@sentex.net> To: Pieter de Goeje <pieter@degoeje.nl>, freebsd-performance@freebsd.org Cc: Ivan Voras <ivoras@freebsd.org> Subject: Re: intel i7 and Hyperthreading Message-ID: <200812231505.mBNF50Bu030894@lava.sentex.ca> In-Reply-To: <200812231122.02892.pieter@degoeje.nl> References: <200812192214.mBJMEj2Q009511@lava.sentex.ca> <giqce6$69o$1@ger.gmane.org> <200812231122.02892.pieter@degoeje.nl>
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At 05:22 AM 12/23/2008, Pieter de Goeje wrote:
>On Tuesday 23 December 2008, Ivan Voras wrote:
> > Mike Tancsa wrote:
> > > Just got our first board to play around with and unlike in the past,
> > > having hyperthreading enabled seems to help performance.... At least in
> > > buildworld tests.
> > >
> > > doing a make -j4 vs -j6 make -j8 vs -j10 gives
> > >
> > > -j buildworld time % improvement over -j4
> > > 4 13:57
> > > 6 12:11 13%
> > > 8 11:32 18%
> > > 10 11:43 17%
> >
> > Thanks for posting this!
>
>What's missing is build times with hyperthreading disabled.
>make buildworld -j10 could easily be faster than -j4 even when hyperthreading
>is disabled, because of increased disk I/O concurrency.
>
>11:43 to build world is very fast indeed :-)
With HT disabled in the BIOS
make -j4, 13:48
make -j8, 12:35
so -j4 is about the same, but -j8 does show a bit of an improvement
with HT enabled ( ~9%) ...
---Mike
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