[HH] cores: AMD vs Intel

[Jerry Feldman]

On 03/18/2013 10:03 PM, Federico Lucifredi wrote:
> On Mar 13, 2013, at 1:47 PM, markw at mohawksoft.com wrote:
>
>> The intel chips are 4 cores with four hyper-threads. Hyper-threads are
>> extremely limited pseudo cores, they are basically a parasitic add on a
>> single processing core that shares the instruction processor and
>> instruction cache. Unless the OS does a good job scheduling,
>> hyper-threading will reduce processing performance.
> my assumption is that hyper-threading helps mitigate branch prediction failures, if your app can feed twice the threads, that is.
>
I have some experience with hyper-threading both enhancing performance 
and degrading performance. Our company's product is very CPU intensive 
that uses things like montecarlo simulations does not do well with 
hyperthreading, so we generally turn it off.  but it also can help in a 
non-cpu intensive situation. And, as Federico mentions, helps with 
branch prediction.

-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
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