[mythtvnz] HDHomerun - VLC on Linux - Yes - well sort of!

[Steven Ellis]

On 28/03/2009, at 10:27 PM, Jean-Yves Avenard wrote:

> Hi
>
> 2009/3/28 Tortise <tortise at paradise.net.nz>:
>> If it is hyperthreading that's effectively splitting my CPU in  
>> half, wouldn't I be better to turn it off and make all of it
>> available?
>> When I get a chance to reboot I'll see if I can turn it off in the  
>> mBoard BIOS, unless you suggest otherwise?
>> {Ref http://ubuntuforums.org/showthread.php?p=895077 the ht=on is  
>> not found.}
>
> It's a matter of choice I guess. The reports are rather split on  
> that issue.
>
> Personally, I always turned off hyperthreading in the BIOS, as the
> gains aren't that great when it does make a difference and it can be
> detrimental in many cases.


HT can have some negative affects especially with code that needs a  
true CPU. The benefit really does depend on the core as with well  
behaved code you generally get 1.5 - 1.6 times a single core in  
performance. Occasionally with bad code (usually in my experience  
Java) you might get 90-95% of a core when it thrashes the CPU.

In the case of the VLC testing it won't make a lot of a difference,  
and might occasionally help. The HT code in a modern linux distro  
(read under 3 years old) is pretty good.

Steve


Steven Ellis - Technical Director
OpenMedia Limited
email   - steven at openmedia.co.nz
website - http://www.openmedia.co.nz

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