Messages in this thread | | | Date | Mon, 7 Dec 2009 10:06:09 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: timer interrupt stucks using tickless kernel |
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On Mon, 7 Dec 2009, Ioannis Kyriakopoulos wrote:
> I have configured my kernel (2.6.31.6) so that I get periodic ticks from > the timer interrupt (i.e. tickless is not configured) with a rate determined > by the HZ value. I've also checked the "high resolution timer support" > and also SMP support. The posblem is that the timer is getting incremented > very slowly (way slower than the HZ value), just like it would be if the > kernel was tickless. Is there an explanation for that? How can I get > periodic > timer ticks?
This is what platform? Embedded? Timer is referring to the system time running slow? kernel boot log would be useful.
> AFAI understand, the HPET timer is used through the IO-APIC controller to > trigger the processors (N.B. if the "High Resolution Timer Support" option > wasn't checked, the timer used would be PIT, right?) and each processor's > LAPIC timer is used for time keeping. Please correct me if I am wrong. > > Another question is how the LAPIC timner's rate is determined? In my case, > it seams that an interurpt by LAPIC timer is generated very appoximately > 0.25 sec (that is HZ which is 1000 * 4) but I can't understand why.
You could have 4 processors that each need a timer interrupt at 1000 HZ?
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