Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 20 Dec 2008 15:53:06 -0500
From:      michael <michael.copeland@gmail.com>
To:        Brett Glass <brett@lariat.net>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: Status of hyperthreading in FreeBSD
Message-ID:  <494D5B32.50806@gmail.com>
In-Reply-To: <200812202039.NAA10290@lariat.net>
References:  <200812202039.NAA10290@lariat.net>

next in thread | previous in thread | raw e-mail | index | archive | help


Brett Glass wrote:
> "Netbooks" based on Intel's "Atom" microprocessor are turning into big 
> hits this Christmas season. The Atom, a super-low-power x86 processor, 
> is an "in-order" machine, which means that except for a few special 
> cases it can spend a lot of time waiting for data to arrive when it 
> encounters a cache miss. So, hyperthreading may make sense on this 
> kind of processor as compared to one with out-of-order execution.
>
> Which raises a question: What's the status of FreeBSD's support for 
> hyperthreading? As far as I know, after it was revealed that some 
> processes on a machine with hyperthreading could "spy" on others, and 
> also that hyperthreading didn't always improve performance on high end 
> processors, the feature was turned off by default. But on single-user 
> machines, or on servers where the CPU was likely to be shared by two 
> processes that were both privileged anyway, it might make sense to 
> re-enable it. But has this feature of the scheduler been maintained 
> well enough for this to be a good idea? If not, would it worth looking 
> into updating it so that FreeBSD runs well on the Atom?
>
> --Brett Glass
>
as far as i know, just enabling smp will allow ht to function. also, i 
don't know if intel changed ht in the new atom processor, they could have.
> _______________________________________________
> freebsd-questions@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to 
> "freebsd-questions-unsubscribe@freebsd.org"



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?494D5B32.50806>