Is hyperthreading necessary at all?
I heard if you turn it off, applications will use the processor as a whole. And not parts of it.
Is that true?
Full Version: Hyperthreading
I have a question..
Is hyperthreading necessary at all?
I heard if you turn it off, applications will use the processor as a whole. And not parts of it.
Is that true?
Is hyperthreading necessary at all?
I heard if you turn it off, applications will use the processor as a whole. And not parts of it.
Is that true?
Hyperthreading merely just take the unused CPU resources to run another task. As for the benefits, it all depends on how much resources is available.
If you run multiple threaded applications, you may benefit from hyperthreading otherwise there is no benefit.
Check out http://en.wikipedia.org/wiki/Hyper-threading
If you run multiple threaded applications, you may benefit from hyperthreading otherwise there is no benefit.
Check out http://en.wikipedia.org/wiki/Hyper-threading
Easily said, hyperthreading allows two busses to communicate with the CPU (so instead of a single 400MHz bus, you'd get two 400MHz busses!). Intel claims 30% speed improvements.
In a server environment, you WILL get speed improvements by using multi-threading, as you're always dealing with multiple processes and threads.
Necessary? Not quite. But it can be an improvement.
In a server environment, you WILL get speed improvements by using multi-threading, as you're always dealing with multiple processes and threads.
Necessary? Not quite. But it can be an improvement.
> Easily said, hyperthreading allows two busses to communicate with the CPU (so instead of a single 400MHz bus, you'd get two 400MHz busses!).
Are you sure about that
Are you sure about that
I heard disabling the hyperthreading lets one process use the entire processor?
QUOTE (paulius @ Jan 23 2007, 04:26 AM) 
Easily said, hyperthreading allows two busses to communicate with the CPU (so instead of a single 400MHz bus, you'd get two 400MHz busses!). Intel claims 30% speed improvements.
Pretty sure that is NOT correct. On a single core chip you only have a single bus, the HT just lets you use more of that bus.
Alot of times on servers there is very little to no improvement or even a decrease in performance from it.
> I heard disabling the hyperthreading lets one process use the entire processor?
Only one thread is typically ever active on the processor even though the entire processor isn't active at once. Hyperthreading attempts to allow two threads using non-competing resources to run on various parts of the processor simultaneously maximizing usage of the CPU by presenting the illusion of two separate processors.
However certain architectural choices in the pentium chip cause one thread that is waiting on some external condition before it can execute, to go into a loop until it is available (in certain circumstances dictated by the structure of that specific application). It wastes power and ties up the processor doing things that are essentially null operations. Generally HT results in an improvement, but certain applications may be adversely affected. Not being a CPU engineer, I admit I don't really understand it fully. But I can pretend
Only one thread is typically ever active on the processor even though the entire processor isn't active at once. Hyperthreading attempts to allow two threads using non-competing resources to run on various parts of the processor simultaneously maximizing usage of the CPU by presenting the illusion of two separate processors.
However certain architectural choices in the pentium chip cause one thread that is waiting on some external condition before it can execute, to go into a loop until it is available (in certain circumstances dictated by the structure of that specific application). It wastes power and ties up the processor doing things that are essentially null operations. Generally HT results in an improvement, but certain applications may be adversely affected. Not being a CPU engineer, I admit I don't really understand it fully. But I can pretend
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