Re: numa_alloc_onnode does not allocate on node passed as argument

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Hi Andres

I will poke around this on the weekend on my NUMA machine.
Can you also attach your kernel config please?

Thank you.

On Wed, Oct 22, 2014 at 12:40 PM, Andres Nötzli <noetzli@xxxxxxxxxxxx> wrote:
> Hi Elena,
>
> Thank you very much for your quick reply! numa_set_strict(1) and numa_set_strict(0) both result in the wrong output. I did not change the default policy.
>
> numa_get_membind returns 1 for all nodes before and after numa_run_on_node.
> numa_get_interleave_mask returns 0 for all nodes.
> numa_get_run_node_mask is all 1s before and 0010 after numa_run_on_node.
>
> The machine config (the CPUs are all Intel(R) Xeon(R) CPU E5-4657L v2 @ 2.40GHz):
>
> $ numactl --hardware
> available: 4 nodes (0-3)
> node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 48 49 50 51 52 53 54 55 56 57 58 59
> node 0 size: 262093 MB
> node 0 free: 966 MB
> node 1 cpus: 12 13 14 15 16 17 18 19 20 21 22 23 60 61 62 63 64 65 66 67 68 69 70 71
> node 1 size: 262144 MB
> node 1 free: 82 MB
> node 2 cpus: 24 25 26 27 28 29 30 31 32 33 34 35 72 73 74 75 76 77 78 79 80 81 82 83
> node 2 size: 262144 MB
> node 2 free: 102 MB
> node 3 cpus: 36 37 38 39 40 41 42 43 44 45 46 47 84 85 86 87 88 89 90 91 92 93 94 95
> node 3 size: 262144 MB
> node 3 free: 113 MB
> node distances:
> node   0   1   2   3
>   0:  10  20  30  20
>   1:  20  10  20  30
>   2:  30  20  10  20
>   3:  20  30  20  10
>
> Thanks again,
> Andres
>
>> On 22 Oct 2014, at 06:12, Elena Ufimtseva <ufimtseva@xxxxxxxxx> wrote:
>>
>> On Tue, Oct 21, 2014 at 11:47 PM, Andres Nötzli <noetzli@xxxxxxxxxxxx> wrote:
>>> Hi everyone,
>>>
>>> I am experiencing a weird problem. When using numa_alloc_onnode repeatedly to allocate memory, it does not allocate memory on the node passed as an argument.
>>>
>>> Sample code:
>>> #include <numa.h>
>>> #include <numaif.h>
>>> #include <iostream>
>>> using namespace std;
>>>
>>> void find_memory_node_for_addr(void* ptr) {
>>>   int numa_node = -1;
>>>   if(get_mempolicy(&numa_node, NULL, 0, ptr, MPOL_F_NODE | MPOL_F_ADDR) < 0)
>>>      cout << "WARNING: get_mempolicy failed" << endl;
>>>   cout << numa_node << endl;
>>> }
>>>
>>> int main() {
>>>   int64_t* x;
>>>   int64_t n = 5000;
>>>   //numa_set_preferred(1);
>>>
>>>   numa_run_on_node(2);
>>>   for(int i = 0; i < 20; i++) {
>>>      size_t s = n * sizeof(int64_t);
>>>      x = (int64_t*)numa_alloc_onnode(s, 1);
>>>      for(int j = 0; j < n; j++)
>>>         x[j] = j + i;
>>>      find_memory_node_for_addr(x);
>>>   }
>>>
>>>   return 0;
>>> }
>>>
>>> Output:
>>> 1
>>> 1
>>> 1
>>> 2
>>> 1
>>> 2
>>> 1
>>> 2
>>> 1
>>> 2
>>> 1
>>> 2
>>> 1
>>> 2
>>> 1
>>> 2
>>> 1
>>> 2
>>> 1
>>> 2
>>>
>>> When uncommenting the line "numa_set_preferred(1);”, the output is all 1s as expected. Am I doing something wrong? Have you seen similar issues?
>>>
>>> I am running Ubuntu 12.04.5 LTS:
>>> $ cat /proc/version
>>> Linux version 3.2.0-29-generic (buildd@allspice) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012
>>>
>>> I am using libnuma 2.0.10 but I’ve had the same problem with 2.0.8~rc3-1.
>>>
>>> Thank you very much,
>>> Andres
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>>
>> Hi Andres
>>
>> Can you try to use strict policy by calling numa_set_strict?
>>
>> If you comment out setting the preferred node, the default policy is
>> in action (I assume you did no change it, not for the process, not
>> system wide) which is preferred also.
>> But here you set preferred to a specific node and manual says, the
>> default for process is to allocate on the node it runs.
>> So I wonder what is the cpu affinity for this process looks like...
>> Also maybe just to confirm you can check the policy from within your
>> running code?
>>
>> Can you also post the machine NUMA config?
>>
>> --
>> Elena
>
>



-- 
Elena
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