Re: [PATCH RFC v2 0/7] xen: vNUMA introduction

[George Dunlap <george.dunlap@eu.citrix.com>]

On 13/09/13 09:49, Elena Ufimtseva wrote:
> This series of patches introduces vNUMA topology awareness and
> provides interfaces and data structures to enable vNUMA for
> PV domU guests.
>
> vNUMA topology support should be supported by PV guest kernel.
> Corresponging patches should be applied.
>
> Introduction
> -------------
>
> vNUMA topology is exposed to the PV guest to improve performance when running
> workloads on NUMA machines.
> XEN vNUMA implementation provides a way to create vNUMA-enabled guests on NUMA/UMA
> and map vNUMA topology to physical NUMA in a optimal way.
>
> XEN vNUMA support
>
> Current set of patches introduces subop hypercall that is available for enlightened
> PV guests with vNUMA patches applied.
>
> Domain structure was modified to reflect per-domain vNUMA topology for use in other
> vNUMA-aware subsystems (e.g. ballooning).
>
> libxc
>
> libxc provides interfaces to build PV guests with vNUMA support and in case of NUMA
> machines provides initial memory allocation on physical NUMA nodes. This implemented by
> utilizing nodemap formed by automatic NUMA placement. Details are in patch #3.
>
> libxl
>
> libxl provides a way to predefine in VM config vNUMA topology - number of vnodes,
> memory arrangement, vcpus to vnodes assignment, distance map.
>
> PV guest
>
> As of now, only PV guest can take advantage of vNUMA functionality. vNUMA Linux patches
> should be applied and NUMA support should be compiled in kernel.
>
> Example of booting vNUMA enabled pv domU:
>
> NUMA machine:
> cpu_topology           :
> cpu:    core    socket     node
>    0:       0        0        0
>    1:       1        0        0
>    2:       2        0        0
>    3:       3        0        0
>    4:       0        1        1
>    5:       1        1        1
>    6:       2        1        1
>    7:       3        1        1
> numa_info              :
> node:    memsize    memfree    distances
>     0:     17664      12243      10,20
>     1:     16384      11929      20,10
>
> VM config:
>
> memory = 16384
> vcpus = 8
> name = "rcbig"
> vnodes = 8
> vnumamem = "2g, 2g, 2g, 2g, 2g, 2g, 2g, 2g"
> vcpu_to_vnode ="5 6 7 4 3 2 1 0"

This was a bit confusing for me as the table above and the config below 
don't seem to be the same.

> Patchset applies to latest Xen tree
> commit e008e9119d03852020b93e1d4da9a80ec1af9c75
> Available at http://git.gitorious.org/xenvnuma/xenvnuma.git

Thanks for the git repo.  It's probably a good idea in the future to 
make a branch for each series of patches you post -- e.g., vnuma-v2 or 
something like that -- so that even if you do more updates / development 
people can still have access to the old set of patches. (Or have access 
to the old set while you are preparing the new set.)

  -George