intel vt versus amd-v?

[Robert P. J. Day]

  a friend wants to buy a server (probably dell) with HW virt support,
and is wondering if there are any current clear advantages of intel
over amd.  the only observation i had time to make was that, if one
checks out entry-level servers from dell (ballpark $1000 cdn), the amd
opteron systems appear to be somewhat less expensive than equivalent
intel-based systems.

  further thoughts?

rday
--

========================================================================
Robert P. J. Day                               Waterloo, Ontario, CANADA

        Linux Consulting, Training and Annoying Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Linked In:                             http://www.linkedin.com/in/rpjday
Twitter:                                       http://twitter.com/rpjday
========================================================================

[Richard W.M. Jones]

On Fri, Jun 05, 2009 at 11:57:14AM -0400, Robert P. J. Day wrote:
>    a friend wants to buy a server (probably dell) with HW virt
> support,
>  and is wondering if there are any current clear advantages of intel
>  over amd.  the only observation i had time to make was that, if one
>  checks out entry-level servers from dell (ballpark $1000 cdn), the amd
>  opteron systems appear to be somewhat less expensive than equivalent
>  intel-based systems.
>  
>    further thoughts? 
The more recent Intel and AMD parts have extra virtualization features
which make virtualization more efficient -- primarily Intel Extended
Page Tables (EPT) and AMD Nested Page Tables (NPT).  So your friend
should look at the chips which support that, basically Intel Nehalem
and the quad-core AMD Opterons (previously known as Barcelona).

If he wants to assign devices directly to guests, maybe look at Intel VT-d
/ AMD IOMMU.  Not used it myself.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
Read my programming blog: http://rwmj.wordpress.com
Fedora now supports 75 OCaml packages (the OPEN alternative to F#)
http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora

[Robert P. J. Day]

On Fri, 5 Jun 2009, Richard W.M. Jones wrote:

>  On Fri, Jun 05, 2009 at 11:57:14AM -0400, Robert P. J. Day wrote:
>  >   a friend wants to buy a server (probably dell) with HW virt support,
>  > and is wondering if there are any current clear advantages of intel
>  > over amd.  the only observation i had time to make was that, if one
>  > checks out entry-level servers from dell (ballpark $1000 cdn), the amd
>  > opteron systems appear to be somewhat less expensive than equivalent
>  > intel-based systems.
>  >
>  >   further thoughts?
>
>  The more recent Intel and AMD parts have extra virtualization
>  features which make virtualization more efficient -- primarily Intel
>  Extended Page Tables (EPT) and AMD Nested Page Tables (NPT).  So
>  your friend should look at the chips which support that, basically
>  Intel Nehalem and the quad-core AMD Opterons (previously known as
>  Barcelona). 
  NPT is what AMD is now calling "Rapid Virtualization Indexing", yes?

rday
--

========================================================================
Robert P. J. Day                               Waterloo, Ontario, CANADA

        Linux Consulting, Training and Annoying Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Linked In:                             http://www.linkedin.com/in/rpjday
Twitter:                                       http://twitter.com/rpjday
========================================================================

[Richard W.M. Jones]

On Fri, Jun 05, 2009 at 04:21:00PM -0400, Robert P. J. Day wrote:
>  On Fri, 5 Jun 2009, Richard W.M. Jones wrote:
>  > On Fri, Jun 05, 2009 at 11:57:14AM -0400, Robert P. J. Day wrote:
>  > >   a friend wants to buy a server (probably dell) with HW virt support,
>  > > and is wondering if there are any current clear advantages of intel
>  > > over amd.  the only observation i had time to make was that, if one
>  > > checks out entry-level servers from dell (ballpark $1000 cdn), the amd
>  > > opteron systems appear to be somewhat less expensive than equivalent
>  > > intel-based systems.
>  > >
>  > >   further thoughts?
>  >
>  > The more recent Intel and AMD parts have extra virtualization
>  > features which make virtualization more efficient -- primarily Intel
>  > Extended Page Tables (EPT) and AMD Nested Page Tables (NPT).  So
>  > your friend should look at the chips which support that, basically
>  > Intel Nehalem and the quad-core AMD Opterons (previously known as
>  > Barcelona).
>  
>    NPT is what AMD is now calling "Rapid Virtualization Indexing", yes? 
I haven't heard it called that til now, but it does look like
their marketing name for NPT, yes.

BTW(1) some AMD machines need to have virtualization enabled in
the BIOS.

BTW(2) to decode the /proc/cpuinfo flags, look here:
http://lxr.linux.no/linux+v2.6.29/arch/x86/include/asm/cpufeature.h
EPT is a flag, but NPT isn't (you have to look in the kernel messages
when loading the KVM module to see if NPT is supported).

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
Read my programming blog: http://rwmj.wordpress.com
Fedora now supports 75 OCaml packages (the OPEN alternative to F#)
http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora

[Ask Bjørn Hansen]

On Jun 5, 2009, at 13:41, Richard W.M. Jones wrote:

>  BTW(1) some AMD machines need to have virtualization enabled in
>  the BIOS. 
Our SuperMicro/Intel BIOS'es come with it disabled by default, too.

  - ask


-- 
Ask Bjørn Hansen, Develooper LLC
http://www.develooper.com/

[Richard W.M. Jones]

On Fri, Jun 05, 2009 at 01:55:26PM -0700, Ask Bjørn Hansen wrote:
>  On Jun 5, 2009, at 13:41, Richard W.M. Jones wrote:
>
> > BTW(1) some AMD machines need to have virtualization enabled in
> > the BIOS.
>
>  Our SuperMicro/Intel BIOS'es come with it disabled by default, too. 
Yeah I got that the wrong way round.  Virtualization can be
disabled on Intel machines, but _not_ on AMD machines.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://et.redhat.com/~rjones/virt-top

[Robert L Cochran]

On 06/05/2009 01:47 PM, Richard W.M. Jones wrote:
>  On Fri, Jun 05, 2009 at 11:57:14AM -0400, Robert P. J. Day wrote:
>     
> >    a friend wants to buy a server (probably dell) with HW virt support,
> > and is wondering if there are any current clear advantages of intel
> > over amd.  the only observation i had time to make was that, if one
> > checks out entry-level servers from dell (ballpark $1000 cdn), the amd
> > opteron systems appear to be somewhat less expensive than equivalent
> > intel-based systems.
> >
> >    further thoughts?
> >      
>
>  The more recent Intel and AMD parts have extra virtualization features
>  which make virtualization more efficient -- primarily Intel Extended
>  Page Tables (EPT) and AMD Nested Page Tables (NPT).  So your friend
>  should look at the chips which support that, basically Intel Nehalem
>  and the quad-core AMD Opterons (previously known as Barcelona).
>
>  If he wants to assign devices directly to guests, maybe look at Intel VT-d
>  / AMD IOMMU.  Not used it myself.
>
>  Rich.
>
>      
What a shame...I don't have a Nehalem processor in my Dell Latitude 
E6400...I wonder if I can just buy the mobile version of a Nehalem chip 
and replace my P9500 with it...

[root@deafeng3 ~]# exit
logout
[rlc@deafeng3 ~]$ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : Intel(R) Core(TM)2 Duo CPU P9500 @ 2.53GHz
stepping : 6
cpu MHz : 800.000
cache size : 6144 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat 
pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm 
constant_tsc arch_perfmon pebs bts rep_good pni dtes64 monitor ds_cpl 
vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 lahf_lm tpr_shadow vnmi 
flexpriority
bogomips : 5054.28
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
....
[processor 1 info duplicates above]
....


Bob

[Don Dutile]

Robert L Cochran wrote:
>  
>  
>  On 06/05/2009 01:47 PM, Richard W.M. Jones wrote:
> > On Fri, Jun 05, 2009 at 11:57:14AM -0400, Robert P. J. Day wrote:
> >   
> >>    a friend wants to buy a server (probably dell) with HW virt support,
> >> and is wondering if there are any current clear advantages of intel
> >> over amd.  the only observation i had time to make was that, if one
> >> checks out entry-level servers from dell (ballpark $1000 cdn), the amd
> >> opteron systems appear to be somewhat less expensive than equivalent
> >> intel-based systems.
> >>
> >>    further thoughts?
> >>      
> >
> > The more recent Intel and AMD parts have extra virtualization features
> > which make virtualization more efficient -- primarily Intel Extended
> > Page Tables (EPT) and AMD Nested Page Tables (NPT).  So your friend
> > should look at the chips which support that, basically Intel Nehalem
> > and the quad-core AMD Opterons (previously known as Barcelona).
> >
> > If he wants to assign devices directly to guests, maybe look at Intel
> > VT-d
> > / AMD IOMMU.  Not used it myself.
> >
> > Rich.
> >
> >    
>  What a shame...I don't have a Nehalem processor in my Dell Latitude
>  E6400...I wonder if I can just buy the mobile version of a Nehalem chip
>  and replace my P9500 with it...
>   
If you have a Dell E6400, your laptop has Intel EPT & Intel VT-d
(as does the E6500).
Make sure virtualization is turned on in the bios
(I think there's two virtualization switches -- one for CPU virtualization,
and one for IO (vt-d/iommu) virtualization).

- Don (happy owner of E6500... and the above reasons why I choose it.)

>  [root@deafeng3 ~]# exit
>  logout
>  [rlc@deafeng3 ~]$ cat /proc/cpuinfo
>  processor : 0
>  vendor_id : GenuineIntel
>  cpu family : 6
>  model : 23
>  model name : Intel(R) Core(TM)2 Duo CPU P9500 @ 2.53GHz
>  stepping : 6
>  cpu MHz : 800.000
>  cache size : 6144 KB
>  physical id : 0
>  siblings : 2
>  core id : 0
>  cpu cores : 2
>  apicid : 0
>  initial apicid : 0
>  fpu : yes
>  fpu_exception : yes
>  cpuid level : 10
>  wp : yes
>  flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat
>  pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm
>  constant_tsc arch_perfmon pebs bts rep_good pni dtes64 monitor ds_cpl
>  vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 lahf_lm tpr_shadow vnmi
>  flexpriority
>  bogomips : 5054.28
>  clflush size : 64
>  cache_alignment : 64
>  address sizes : 36 bits physical, 48 bits virtual
>  power management:
>  ....
>  [processor 1 info duplicates above]
>  ....
>  
>  
>  Bob
>  
>  
>  
>  
>  ------------------------------------------------------------------------
>  
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