* Re: a question about the numa information on my machine
2011-06-22 6:13 ` a question about the numa information on my machine Chia-Hung Lin
@ 2011-06-22 13:13 ` Lee Schermerhorn
2011-06-22 15:17 ` Andi Kleen
2011-07-19 3:01 ` Chia-Hung Lin
2 siblings, 0 replies; 6+ messages in thread
From: Lee Schermerhorn @ 2011-06-22 13:13 UTC (permalink / raw)
To: Chia-Hung Lin; +Cc: linux-numa
On Wed, 2011-06-22 at 14:13 +0800, Chia-Hung Lin wrote:
> Hi,
>
> I don't know if this post is appropriately for this board. (If not,
> which forum should I post to?)
>
> I am wondering if my machine is configured right.
> My machine equipped with two Intel Xeon E5640 CPUs (each has 4 cores).
> The red hat version is Red Hat Enterprise 5.5 and linux kernel is
> 2.6.18-194.el5
> My question is when I check /sys/devices/system/node, there is only
> one node0 directory.
> The information displayed by "numactl --show" is
> policy: default
> preferred node: current
> physcpubind: 0 1 2 3 4 5 6 7
> cpubind: 0
> nodebind: 0
> membind: 0
>
> Why there is only one node instead of two? Is there any thing wrong
> with my machine?
> Also, I found a message in dmesg :
> No NUMA configuration found
> Faking a node at 0000000000000000-0000000318000000
>
> What should be a NUMA configuration look like?
> Another thing I think strange is the BIOS setting. Its default is SMP.
David: in SMP mode, the bios will interleave/stripe the memory of the 2
sockets [assuming you have memory on both sockets?] into a single "node"
and will [I think] omit the ACPI numa topology table [SRAT]. This is
consistent with the "No NUMA configuration found" message you're seeing.
> When I try to change it to NUMA, I can only see one CPU after re-booting.
> Is it normal? (the machine model is Dell T5500)
Don't know about that. Doesn't sound right. Do you still see "No NUMA
configuration..."? What does "numactl --hardware" show in this case?
You might try booting with 'debug' [instead of 'quiet' -- default in
RHEL 5.5] and see whether the console log or dmesg file give any clues.
> It will be very helpful if you can give me some direction.
>
> Thanks a lot.
Regards,
Lee
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: a question about the numa information on my machine
2011-06-22 6:13 ` a question about the numa information on my machine Chia-Hung Lin
2011-06-22 13:13 ` Lee Schermerhorn
@ 2011-06-22 15:17 ` Andi Kleen
2011-06-23 9:35 ` Chia-Hung Lin
2011-07-19 3:01 ` Chia-Hung Lin
2 siblings, 1 reply; 6+ messages in thread
From: Andi Kleen @ 2011-06-22 15:17 UTC (permalink / raw)
To: Chia-Hung Lin; +Cc: linux-numa
>
> Why there is only one node instead of two? Is there any thing wrong
> with my machine?
You have to disable "Node interleaving" (or similarly named) in the BIOS
to get NUMA support in the OS.
-Andi
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: a question about the numa information on my machine
2011-06-22 15:17 ` Andi Kleen
@ 2011-06-23 9:35 ` Chia-Hung Lin
0 siblings, 0 replies; 6+ messages in thread
From: Chia-Hung Lin @ 2011-06-23 9:35 UTC (permalink / raw)
To: Andi Kleen; +Cc: linux-numa
On Wed, Jun 22, 2011 at 11:17 PM, Andi Kleen <andi@firstfloor.org> wrote:
>>
>> Why there is only one node instead of two? Is there any thing wrong
>> with my machine?
>
> You have to disable "Node interleaving" (or similarly named) in the BIOS
> to get NUMA support in the OS.
>
> -Andi
>
There is a "Memory Node Interleaving" section in BIOS and two options
that I can choose :
SMP or NUMA
=> no disabled option
Either one will get "No NUMA configuration found" in dmesg
And I don't see any ACPI SRAT information during boot.
the boot command is "swiotlb=65536 ro root=LABEL=/ quiet numa=acpi"
Is it correct? (I have no right to change it to debug mode to see if
anything wrong)
David
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: a question about the numa information on my machine
2011-06-22 6:13 ` a question about the numa information on my machine Chia-Hung Lin
2011-06-22 13:13 ` Lee Schermerhorn
2011-06-22 15:17 ` Andi Kleen
@ 2011-07-19 3:01 ` Chia-Hung Lin
2011-07-19 4:05 ` Andi Kleen
2 siblings, 1 reply; 6+ messages in thread
From: Chia-Hung Lin @ 2011-07-19 3:01 UTC (permalink / raw)
To: linux-numa
Hi, all,
I just identified the problem.
I use Intel VTune Amplifier for profiling and it asks me to disable
C-States to avoid system hanging.
Today, I popped up the idea to try to enable it and checked the
numa information again.
It is o.k.! So, C-States is critical for NUMA in Nehalem Architecture?
I don't know if it is always the case or just the case on my model.
David
On Wed, Jun 22, 2011 at 2:13 PM, Chia-Hung Lin <ch1028.lin@gmail.com> wrote:
> Hi,
>
> I don't know if this post is appropriately for this board. (If not,
> which forum should I post to?)
>
> I am wondering if my machine is configured right.
> My machine equipped with two Intel Xeon E5640 CPUs (each has 4 cores).
> The red hat version is Red Hat Enterprise 5.5 and linux kernel is
> 2.6.18-194.el5
> My question is when I check /sys/devices/system/node, there is only
> one node0 directory.
> The information displayed by "numactl --show" is
> policy: default
> preferred node: current
> physcpubind: 0 1 2 3 4 5 6 7
> cpubind: 0
> nodebind: 0
> membind: 0
>
> Why there is only one node instead of two? Is there any thing wrong
> with my machine?
> Also, I found a message in dmesg :
> No NUMA configuration found
> Faking a node at 0000000000000000-0000000318000000
>
> What should be a NUMA configuration look like?
> Another thing I think strange is the BIOS setting. Its default is SMP.
> When I try to change it to NUMA, I can only see one CPU after re-booting.
> Is it normal? (the machine model is Dell T5500)
> It will be very helpful if you can give me some direction.
>
> Thanks a lot.
>
> David Lin
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: a question about the numa information on my machine
2011-07-19 3:01 ` Chia-Hung Lin
@ 2011-07-19 4:05 ` Andi Kleen
0 siblings, 0 replies; 6+ messages in thread
From: Andi Kleen @ 2011-07-19 4:05 UTC (permalink / raw)
To: Chia-Hung Lin; +Cc: linux-numa
On Tue, Jul 19, 2011 at 11:01:08AM +0800, Chia-Hung Lin wrote:
> Hi, all,
>
> I just identified the problem.
> I use Intel VTune Amplifier for profiling and it asks me to disable
> C-States to avoid system hanging.
> Today, I popped up the idea to try to enable it and checked the
> numa information again.
> It is o.k.! So, C-States is critical for NUMA in Nehalem Architecture?
No, C-states are orthogonal to NUMA.
-Andi
^ permalink raw reply [flat|nested] 6+ messages in thread