hyperthreading and CPU resource measurement

Cochise · Post by **Cochise** » Tue May 23, 2006 10:33 am

Just wondering about CPU load measurement with HT enabled. Do values displayed by task manager represent the half of the real load for single core CPUs?

[ This Message was edited by: Cochise on 2006-05-23 11:34 ]

Cochise · Post by **Cochise** » Wed May 24, 2006 5:14 am

Maybe dumb question.

However, I made some try.
Using HT a CPU load of more than 51% is displayed for tasks requiring 100% of resources with HT disabled.

[ This Message was edited by: Cochise on 2006-05-24 06:16 ]

valis · Post by **valis** » Wed May 24, 2006 5:21 am

Cpu load will distribute evenly across processors when an app isn't threaded by the programmer so that it has cpu affinity. This means that a 51% load across 'both cpus' is 102%. HT is integer only so imo you're not going to see truly massive performance increases, although specific benchmarks by certain sites and companies may make it seem so.

Cochise · Post by **Cochise** » Wed May 24, 2006 5:32 am

I havent't done thorough tests, but it seems CPU require a bit more power with HT enabled. Its temperature looks more than 1°C higher (>51% load)

[ This Message was edited by: Cochise on 2006-05-24 06:34 ]

Cochise · Post by **Cochise** » Wed May 24, 2006 9:12 am

Repeated the test.
NO effective temperature difference noticed.

However in HT mode CPU load can reach peaks up to 74%

:?

valis · Post by **valis** » Thu May 25, 2006 5:46 am

Is it spiking?

bronYaur · Post by **bronYaur** » Thu May 25, 2006 7:38 am

hyperthreading is only cache and register enance of cpu the OS look the register of cpu like dual processor

[ This Message was edited by: bronYaur on 2006-05-25 08:39 ]

Cochise · Post by **Cochise** » Fri May 26, 2006 4:08 am

Spiking? Sorry, I can't exactly understand what you mean.
I can sometimes read that value on a very short lapse...