Xen users - Sep 2008 - 3.2.1+ HVM + HAP + NUMA - Poor Memory Performance

Hi Everyone,

 

I am running 3.2.1 on Centos 5.2 with HAP enabled, NUMA enabled, ACPI
enabled and the dom0 allocated 512Mb. I have setup a single core 1Gb VM
for performance testing under Windows 2008 Server. Most CPU results are
within a few percent of theoretical max but Memory performance is about
half what I expected.

I get 3.22Gb/Sec Sandra 2009 Memory performance for a single Opteron
8350 core on dual channel DDR2-667, a single Barcelona core should
manage about 6Gb/sec in this config AFAIK. Without pinning the VCPU
performance is an even worse 2.67GB/sec.

 

Is there likely something wrong with my NUMA config? Anyone have any
benchmark results to share on Barcelona with HAP enabled? Do I need to
pin Dom0 to a particular CPU?

 

HAP looks OK:

(XEN)     VCPU0: CPU4 [has=F] flags=1 upcall_pend = 00, upcall_mask = 00
dirty_cpus={4} cpu_affinity={4}

(XEN)     paging assistance: hap, 4 levels

 

NUMA looks OK:

nr_cpus                : 8

nr_nodes               : 2

cores_per_socket       : 4

threads_per_core       : 1

cpu_mhz                : 2000

 

Thanks in advance,

 

Rob


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