On 06/03/13 12:32, Daniel P. Berrange wrote:
On Tue, May 28, 2013 at 02:35:50PM +0200, Peter Krempa wrote:
The RPC limits for cpu maps didn't allow to use libvirt on ultra big boxes. This patch increases size of the limits to support a maximum of 4096 cpus on the host with the built-in maximum of 256 cpus per guest. The full cpu map of such a system takes 128 kilobytes and the map for vcpu pinning is 512 bytes long. --- src/remote/remote_protocol.x | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/src/remote/remote_protocol.x b/src/remote/remote_protocol.x index 1ebbce7..a94e0db 100644 --- a/src/remote/remote_protocol.x +++ b/src/remote/remote_protocol.x @@ -82,13 +82,13 @@ const REMOTE_DOMAIN_ID_LIST_MAX = 16384; const REMOTE_DOMAIN_NAME_LIST_MAX = 16384;
/* Upper limit on cpumap (bytes) passed to virDomainPinVcpu. */ -const REMOTE_CPUMAP_MAX = 256; +const REMOTE_CPUMAP_MAX = 512;
/* Upper limit on number of info fields returned by virDomainGetVcpus. */ -const REMOTE_VCPUINFO_MAX = 2048; +const REMOTE_VCPUINFO_MAX = 4096;
/* Upper limit on cpumaps (bytes) passed to virDomainGetVcpus. */ -const REMOTE_CPUMAPS_MAX = 16384; +const REMOTE_CPUMAPS_MAX = 131072;
/* Upper limit on migrate cookie. */ const REMOTE_MIGRATE_COOKIE_MAX = 16384;
4096 sounds large, but I can't help wondering if we should pre-empt the inevitable and go even bigger. In terms of RPC message size, we can afford to allow 16384 host CPUS and 4096 guest CPUS ?
We can do that. The cpu map for a 16384 host with 4096 guest cpus is 8 MiB large. The RPC message limit is almost 16MiB so we should be fine even with those (now seemingly insane) numbers. I'll send a v2 in a moment.
Daniel
Peter