I have dual core ARM v7 ve system. I am trying to run xen on it. From a conceptual level if I have to run 2 os (VM) on xen, then in effect there would 3 VMs running 2 guest os''s for my purpose and the dom0. How would 3 VM''s run on two cores ? Is it possible to affine cores in xen ? =Thanks
On 10/27/2013 09:17 AM, Mj Embd wrote:> I have dual core ARM v7 ve system. I am trying to run xen on it. > From a conceptual level if I have to run 2 os (VM) on xen, then in > effect there would 3 VMs running > 2 guest os''s for my purpose and the dom0. > > How would 3 VM''s run on two cores ? > Is it possible to affine cores in xen ?If it is anything like x86, then you can overbook cores - Xen will manage what gets to run fairly. You can also specify how many cores you want dom0 to use and pin them, as well as specifying how many and which cores domU should run on. Gordan
In my use case VM;s don''t have any physical device, all are owned by dom0. [keyboard, network] I am planning vnc to view the ubuntu''s running in VM''s So I have to pin 1st core for dom0 and on second core my actual VM''s would run ? Would you think it would be a feasible solution in terms of latency ? On Sun, Oct 27, 2013 at 3:03 PM, Gordan Bobic <gordan@bobich.net> wrote:> On 10/27/2013 09:17 AM, Mj Embd wrote: >> >> I have dual core ARM v7 ve system. I am trying to run xen on it. >> From a conceptual level if I have to run 2 os (VM) on xen, then in >> effect there would 3 VMs running >> 2 guest os''s for my purpose and the dom0. >> >> How would 3 VM''s run on two cores ? >> Is it possible to affine cores in xen ? > > > If it is anything like x86, then you can overbook cores - Xen will manage > what gets to run fairly. You can also specify how many cores you want dom0 > to use and pin them, as well as specifying how many and which cores domU > should run on. > > Gordan >-- -mj
It doesn''t matter - any VM can run on any CPU core and none require a dedicated CPU core. If your application is such that you are concerned about latency, the chances are that no virtualization solution is going to be good enough. Otherwise don''t worry about it. Gordan On 10/27/2013 10:40 AM, Mj Embd wrote:> In my use case VM;s don''t have any physical device, all are owned by dom0. > [keyboard, network] I am planning vnc to view the ubuntu''s running in VM''s > So I have to pin 1st core for dom0 and on second core my actual VM''s > would run ? > Would you think it would be a feasible solution in terms of latency ? > > > On Sun, Oct 27, 2013 at 3:03 PM, Gordan Bobic <gordan@bobich.net> wrote: >> On 10/27/2013 09:17 AM, Mj Embd wrote: >>> >>> I have dual core ARM v7 ve system. I am trying to run xen on it. >>> From a conceptual level if I have to run 2 os (VM) on xen, then in >>> effect there would 3 VMs running >>> 2 guest os''s for my purpose and the dom0. >>> >>> How would 3 VM''s run on two cores ? >>> Is it possible to affine cores in xen ? >> >> >> If it is anything like x86, then you can overbook cores - Xen will manage >> what gets to run fairly. You can also specify how many cores you want dom0 >> to use and pin them, as well as specifying how many and which cores domU >> should run on. >> >> Gordan >> > > >
On Sun, 2013-10-27 at 19:27 +0000, Gordan Bobic wrote:> It doesn''t matter - any VM can run on any CPU core and none require a > dedicated CPU core. If your application is such that you are concerned > about latency, the chances are that no virtualization solution is going > to be good enough. Otherwise don''t worry about it.Actually, given the presence of sEDF and the arinc653 schedulers (both of which have RT properties) and the simplicity of the ARM interrupt injection path I think Xen on ARM is probably not in too bad a shape for a soft-ish RT system, at least as a starting point for testing/measuring/improving etc. It depends on the specific requirements of course. Also remember that through cpupools you can split the physical CPUs into RT and non-RT pools, each with their own scheduler and assign domains to the appropriate pool. Ian.