jdk and NUMA

[David Dabbs]

Thank you ramki, for the reply.

What "issues" should might one expect after adding +UseNUMA?




-----Original Message-----
From: Y. S. Ramakrishna [mailto: @oracle.com] 
Sent: Thursday, September 09, 2010 5:31 PM
To: David Dabbs
Subject: Re: jdk and NUMA

Yes, just use +UseNUMA to begin with, and let us know if there are
any issues.

-- ramki

On 09/09/10 12:04, David Dabbs wrote:
> My apologies if this is not the correct place for this question.
> 
> I have a shiny new NUMA-capable Xeon server and want to ensure that my
Java
> app(s) make full use of the hardware.
> So, I ran java (jdk 6u21) -XX:+PrintFlagsFinal and (naively) expected to
see
> UseNUMA := true but did not.
> 
> I found this post
> 
> http://blogs.sun.com/jonthecollector/entry/help_for_the_numa_weary
> 
> If its simply a matter of turning it on that's what I'll do. Any
guidelines
> about use of mumactl or the jdks NUMA "knobs"?
> 
> 
> uname -a
> Linux 2.6.18-128.7.1.el5 #1 SMP Mon Aug 24 08:21:56 EDT 2009 x86_64 x86_64
> x86_64 GNU/Linux
> 
> Linux, CentOS 5
> 
> 
> cat /proc/cpuinfo
> 
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 6
> model           : 26
> model name      : Intel(R) Xeon(R) CPU           E5530  @ 2.40GHz
> stepping        : 5
> cpu MHz         : 2394.112
> cache size      : 8192 KB
> physical id     : 1
> siblings        : 8
> core id         : 0
> cpu cores       : 4
> apicid          : 16
> fpu             : yes
> fpu_exception   : yes
> cpuid level     : 11
> wp              : yes
> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
> cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx
rdtscp
> lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr
> popcnt lahf_lm
> bogomips        : 4791.64
> clflush size    : 64
> cache_alignment : 64
> address sizes   : 40 bits physical, 48 bits virtual
> power management: [8]        
> 
> This repeats for processors 1-15.
> 
> Two physical ids, 0,1.
> 
> 
> 

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