KVM_MAX_VCPUS
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
Quoted 9 lines · Chegu Vinod
Hello,
Wanted to get a clarification about
KVM_MAX_VCPUS(currently set to 254)
inkvm_host.hfile. Thekvm_vcpu*vcpus array is sized based onKVM_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_VCPUSbeing set to 254 and not 255).
Another ID goes to the IO-APIC.
Thanks,
Sasha
Quoted 7 lines · Sasha Levin
Quoted 6 lines · Chegu Vinod
Hello,
Wanted to get a clarification about
KVM_MAX_VCPUS(currently set to 254)
inkvm_host.hfile. Thekvm_vcpu*vcpus array is sized based onKVM_MAX_VCPUS.
(i.e. a max of 254 elements in the array).
Quoted 6 lines
Quoted 3 lines
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_VCPUSbeing 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.
Quoted 8 lines · Gleb Natapov
Quoted 7 lines · Sasha Levin
Quoted 6 lines · Chegu Vinod
Hello,
Wanted to get a clarification about
KVM_MAX_VCPUS(currently set to 254)
inkvm_host.hfile. Thekvm_vcpu*vcpus array is sized based onKVM_MAX_VCPUS.
(i.e. a max of 254 elements in the array).
Quoted 6 lines
Quoted 5 lines
Quoted 3 lines
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_VCPUSbeing 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_VCPUSto 255.
Thanks for clarification! ( We did suspect the IO-APIC...but weren't quite sure).
Vinod
Quoted 5 lines
--
Gleb.
.
For pCPU/core and VCPUS/logical cpu mapping, It should be 8 multiple. 254 is reasonable. Or something I miss?
-----Original Message-----
From: [email protected] [mailto:[email protected]] 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
Quoted 8 lines · Gleb Natapov
Quoted 7 lines · Sasha Levin
Quoted 6 lines · Chegu Vinod
Hello,
Wanted to get a clarification about
KVM_MAX_VCPUS(currently set to 254)
inkvm_host.hfile. Thekvm_vcpu*vcpus array is sized based onKVM_MAX_VCPUS.
(i.e. a max of 254 elements in the array).
Quoted 6 lines
Quoted 5 lines
Quoted 3 lines
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_VCPUSbeing 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_VCPUSto 255.
Thanks for clarification! ( We did suspect the IO-APIC...but weren't quite sure).
Vinod
Quoted 5 lines
--
Gleb.
.
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More majordomo info at http://vger.kernel.org/majordomo-info.html
Quoted 2 lines · MCXS-SH)
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?
Quoted 33 lines
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Vinod, Chegu
Sent: Sunday, October 14, 2012 9:43 PM
To: Gleb Natapov
Cc: Sasha Levin; KVM
Subject: Re:KVM_MAX_VCPUSQuoted 8 lines · Gleb Natapov
Quoted 7 lines · Sasha Levin
Quoted 6 lines · Chegu Vinod
Hello,
Wanted to get a clarification about
KVM_MAX_VCPUS(currently set to 254)
inkvm_host.hfile. Thekvm_vcpu*vcpus array is sized based onKVM_MAX_VCPUS.
(i.e. a max of 254 elements in the array).Quoted 6 lines
Quoted 5 lines
Quoted 3 lines
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_VCPUSbeing 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_VCPUSto 255.Thanks for clarification! ( We did suspect the IO-APIC...but weren't quite sure).
Vinod
Quoted 5 lines
--
Gleb.
.
Quoted 4 lines
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More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Gleb.