Re: Is contiguous hugepages memory still required in latest DPDKs?

[Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>]

On 23/03/2017 16:24, Ruslan Bilovol wrote:
> On 03/22/2017 02:08 PM, Ruslan Bilovol wrote:
>> On 03/21/2017 04:41 PM, Sergio Gonzalez Monroy wrote:
>>> The DPDK will still try to allocate contiguous hugepages.
>>> Since DPDK v16.07 the mempool library is able to create a mempool 
>>> with multiple chunks of memory.
>>> You would still have the contig memory restriction for any other 
>>> DPDK library or app.
>
> Another question: are there any improvements in contiguous hugepages 
> requirements in latest DPDK (v17.02)?
>

Not that I can think of.

Sergio

> Thanks,
> Ruslan
>
>
>>>
>>> Are you pre-allocating hugepages on boot (kernel cmdline) or runtime?
>> I tried both cases, and there is no much difference between them.
>> (I used debug prints in kernel to see physical address of 
>> preallocated hugepages
>>
>> Main issue is that linux kernel memory allocation algorithm was changed
>> with "fair zone allocator policy" commits, and in my case need to
>> pre-allocate 2x or even 3x more hugepages now.
>>
>> Regards,
>> Ruslan
>>
>>>
>>> Sergio
>>>
>>> On 21/03/2017 14:20, Ruslan Bilovol wrote:
>>>> Hi,
>>>>
>>>> Recently after moving to 4.4 Linux kernel we found that DPDK v16.07
>>>> can't find physically contiguous chunk of hugepages memory.
>>>>
>>>> I've tracked this down to kernel commits
>>>>  81c0a2bb515f ("mm: page_alloc: fair zone allocator policy")
>>>>  fff4068cba48 ("mm: page_alloc: revert NUMA aspect of fair 
>>>> allocation policy")
>>>>  4ffeaf3560a5 ("mm: page_alloc: reduce cost of the fair zone 
>>>> allocation policy")
>>>>
>>>> These commits changed default page allocator behavior so it now 
>>>> allocates
>>>> memory proportionally from preferred and lower zones. Hugepages
>>>> are scattered proportionally among few memory zones, so possibility
>>>> to find big physically contiguous chunk of hugepages memory is much 
>>>> lower.
>>>>
>>>> I see that there were some attempts to move from contiguous hugepages
>>>> approach, like http://dpdk.org/ml/archives/dev/2016-March/035201.html
>>>> Also some discussion here: 
>>>> http://dpdk.org/ml/archives/users/2016-October/001050.html
>>>>
>>>> The question: is contiguous hugepages memory still required in 
>>>> latest DPDKs,
>>>> and if not, since which version?
>>>>
>>>> Thanks,
>>>> Ruslan
>>>>
>>>
>>
>