* KVM_MAX_VCPUS
@ 2012-10-13 22:29 Chegu Vinod
2012-10-14 2:32 ` KVM_MAX_VCPUS Sasha Levin
0 siblings, 1 reply; 6+ messages in thread
From: Chegu Vinod @ 2012-10-13 22:29 UTC (permalink / raw)
To: KVM
Hello,
Wanted to get a clarification about KVM_MAX_VCPUS(currently set to 254)
in kvm_host.h file. The kvm_vcpu *vcpus array is sized based on KVM_MAX_VCPUS.
(i.e. a max of 254 elements in the array).
An 8bit APIC id should allow for 256 ID's. Reserving one for Broadcast should
leave 255 ID's. Is there one more ID reserved for some other purpose ? (hence
leading to KVM_MAX_VCPUS being set to 254 and not 255).
Thanks!
Vinod
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KVM_MAX_VCPUS
2012-10-13 22:29 KVM_MAX_VCPUS Chegu Vinod
@ 2012-10-14 2:32 ` Sasha Levin
2012-10-14 9:08 ` KVM_MAX_VCPUS Gleb Natapov
0 siblings, 1 reply; 6+ messages in thread
From: Sasha Levin @ 2012-10-14 2:32 UTC (permalink / raw)
To: Chegu Vinod; +Cc: KVM
On 10/13/2012 06:29 PM, Chegu Vinod wrote:
> Hello,
>
> Wanted to get a clarification about KVM_MAX_VCPUS(currently set to 254)
> in kvm_host.h file. The kvm_vcpu *vcpus array is sized based on KVM_MAX_VCPUS.
> (i.e. a max of 254 elements in the array).
>
> An 8bit APIC id should allow for 256 ID's. Reserving one for Broadcast should
> leave 255 ID's. Is there one more ID reserved for some other purpose ? (hence
> leading to KVM_MAX_VCPUS being set to 254 and not 255).
Another ID goes to the IO-APIC.
Thanks,
Sasha
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KVM_MAX_VCPUS
2012-10-14 2:32 ` KVM_MAX_VCPUS Sasha Levin
@ 2012-10-14 9:08 ` Gleb Natapov
2012-10-14 13:42 ` KVM_MAX_VCPUS Chegu Vinod
0 siblings, 1 reply; 6+ messages in thread
From: Gleb Natapov @ 2012-10-14 9:08 UTC (permalink / raw)
To: Sasha Levin; +Cc: Chegu Vinod, KVM
On Sat, Oct 13, 2012 at 10:32:13PM -0400, Sasha Levin wrote:
> On 10/13/2012 06:29 PM, Chegu Vinod wrote:
> > Hello,
> >
> > Wanted to get a clarification about KVM_MAX_VCPUS(currently set to 254)
> > in kvm_host.h file. The kvm_vcpu *vcpus array is sized based on KVM_MAX_VCPUS.
> > (i.e. a max of 254 elements in the array).
> >
> > An 8bit APIC id should allow for 256 ID's. Reserving one for Broadcast should
> > leave 255 ID's. Is there one more ID reserved for some other purpose ? (hence
> > leading to KVM_MAX_VCPUS being set to 254 and not 255).
>
> Another ID goes to the IO-APIC.
>
This is not really needed on KVM. We can enlarge KVM_MAX_VCPUS to 255.
--
Gleb.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KVM_MAX_VCPUS
2012-10-14 9:08 ` KVM_MAX_VCPUS Gleb Natapov
@ 2012-10-14 13:42 ` Chegu Vinod
2012-10-17 2:57 ` KVM_MAX_VCPUS Wei, Bing (WeiBing, MCXS-SH)
0 siblings, 1 reply; 6+ messages in thread
From: Chegu Vinod @ 2012-10-14 13:42 UTC (permalink / raw)
To: Gleb Natapov; +Cc: Sasha Levin, KVM
On 10/14/2012 2:08 AM, Gleb Natapov wrote:
> On Sat, Oct 13, 2012 at 10:32:13PM -0400, Sasha Levin wrote:
>> On 10/13/2012 06:29 PM, Chegu Vinod wrote:
>>> Hello,
>>>
>>> Wanted to get a clarification about KVM_MAX_VCPUS(currently set to 254)
>>> in kvm_host.h file. The kvm_vcpu *vcpus array is sized based on KVM_MAX_VCPUS.
>>> (i.e. a max of 254 elements in the array).
>>>
>>> An 8bit APIC id should allow for 256 ID's. Reserving one for Broadcast should
>>> leave 255 ID's. Is there one more ID reserved for some other purpose ? (hence
>>> leading to KVM_MAX_VCPUS being set to 254 and not 255).
>> Another ID goes to the IO-APIC.
>>
> This is not really needed on KVM. We can enlarge KVM_MAX_VCPUS to 255.
Thanks for clarification! ( We did suspect the IO-APIC...but weren't
quite sure).
Vinod
>
> --
> Gleb.
> .
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: KVM_MAX_VCPUS
2012-10-14 13:42 ` KVM_MAX_VCPUS Chegu Vinod
@ 2012-10-17 2:57 ` Wei, Bing (WeiBing, MCXS-SH)
2012-10-17 7:21 ` KVM_MAX_VCPUS Gleb Natapov
0 siblings, 1 reply; 6+ messages in thread
From: Wei, Bing (WeiBing, MCXS-SH) @ 2012-10-17 2:57 UTC (permalink / raw)
To: Vinod, Chegu, Gleb Natapov; +Cc: Sasha Levin, KVM
For pCPU/core and VCPUS/logical cpu mapping, It should be 8 multiple. 254 is reasonable. Or something I miss?
-----Original Message-----
From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On Behalf Of Vinod, Chegu
Sent: Sunday, October 14, 2012 9:43 PM
To: Gleb Natapov
Cc: Sasha Levin; KVM
Subject: Re: KVM_MAX_VCPUS
On 10/14/2012 2:08 AM, Gleb Natapov wrote:
> On Sat, Oct 13, 2012 at 10:32:13PM -0400, Sasha Levin wrote:
>> On 10/13/2012 06:29 PM, Chegu Vinod wrote:
>>> Hello,
>>>
>>> Wanted to get a clarification about KVM_MAX_VCPUS(currently set to 254)
>>> in kvm_host.h file. The kvm_vcpu *vcpus array is sized based on KVM_MAX_VCPUS.
>>> (i.e. a max of 254 elements in the array).
>>>
>>> An 8bit APIC id should allow for 256 ID's. Reserving one for Broadcast should
>>> leave 255 ID's. Is there one more ID reserved for some other purpose ? (hence
>>> leading to KVM_MAX_VCPUS being set to 254 and not 255).
>> Another ID goes to the IO-APIC.
>>
> This is not really needed on KVM. We can enlarge KVM_MAX_VCPUS to 255.
Thanks for clarification! ( We did suspect the IO-APIC...but weren't
quite sure).
Vinod
>
> --
> Gleb.
> .
>
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KVM_MAX_VCPUS
2012-10-17 2:57 ` KVM_MAX_VCPUS Wei, Bing (WeiBing, MCXS-SH)
@ 2012-10-17 7:21 ` Gleb Natapov
0 siblings, 0 replies; 6+ messages in thread
From: Gleb Natapov @ 2012-10-17 7:21 UTC (permalink / raw)
To: Wei, Bing (WeiBing, MCXS-SH); +Cc: Vinod, Chegu, Sasha Levin, KVM
On Wed, Oct 17, 2012 at 02:57:15AM +0000, Wei, Bing (WeiBing, MCXS-SH) wrote:
> For pCPU/core and VCPUS/logical cpu mapping, It should be 8 multiple. 254 is reasonable. Or something I miss?
>
I am not sure what do you mean. Can you clarify?
> -----Original Message-----
> From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On Behalf Of Vinod, Chegu
> Sent: Sunday, October 14, 2012 9:43 PM
> To: Gleb Natapov
> Cc: Sasha Levin; KVM
> Subject: Re: KVM_MAX_VCPUS
>
> On 10/14/2012 2:08 AM, Gleb Natapov wrote:
> > On Sat, Oct 13, 2012 at 10:32:13PM -0400, Sasha Levin wrote:
> >> On 10/13/2012 06:29 PM, Chegu Vinod wrote:
> >>> Hello,
> >>>
> >>> Wanted to get a clarification about KVM_MAX_VCPUS(currently set to 254)
> >>> in kvm_host.h file. The kvm_vcpu *vcpus array is sized based on KVM_MAX_VCPUS.
> >>> (i.e. a max of 254 elements in the array).
> >>>
> >>> An 8bit APIC id should allow for 256 ID's. Reserving one for Broadcast should
> >>> leave 255 ID's. Is there one more ID reserved for some other purpose ? (hence
> >>> leading to KVM_MAX_VCPUS being set to 254 and not 255).
> >> Another ID goes to the IO-APIC.
> >>
> > This is not really needed on KVM. We can enlarge KVM_MAX_VCPUS to 255.
>
> Thanks for clarification! ( We did suspect the IO-APIC...but weren't
> quite sure).
>
> Vinod
> >
> > --
> > Gleb.
> > .
> >
>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Gleb.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-10-17 7:21 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-10-13 22:29 KVM_MAX_VCPUS Chegu Vinod
2012-10-14 2:32 ` KVM_MAX_VCPUS Sasha Levin
2012-10-14 9:08 ` KVM_MAX_VCPUS Gleb Natapov
2012-10-14 13:42 ` KVM_MAX_VCPUS Chegu Vinod
2012-10-17 2:57 ` KVM_MAX_VCPUS Wei, Bing (WeiBing, MCXS-SH)
2012-10-17 7:21 ` KVM_MAX_VCPUS Gleb Natapov
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.