lapic timer question
Posted: Sun Sep 05, 2010 12:36 pm
hi i have been working on booting multiple cores and using apic timer to display different threads on each core.
I initialize the lapic timer based on code from http://forum.osdev.org/viewtopic.php?t=10686
If i initialize the timer before the 2nd core is started I get a result of 100Mhz once a second core is started i get a result of 200Mhz (bios also displays this)
I was wondering if anyone new the reason why this happens. It might have to do with the cores speed as windows reports from 800Mhz (cpu speed) and goes upto 2800Mhz adjusted for processor load.
Just a note this happens on real hardware (qemu works fine)
Hardware.
AMD Phenom II 1055T x6
I initialize the lapic timer based on code from http://forum.osdev.org/viewtopic.php?t=10686
If i initialize the timer before the 2nd core is started I get a result of 100Mhz once a second core is started i get a result of 200Mhz (bios also displays this)
I was wondering if anyone new the reason why this happens. It might have to do with the cores speed as windows reports from 800Mhz (cpu speed) and goes upto 2800Mhz adjusted for processor load.
Just a note this happens on real hardware (qemu works fine)
Hardware.
AMD Phenom II 1055T x6