[dpdk-dev] Number of memory channels per processor socket?

[Abhishek Verma]

Thanks Keunhong.

How do i get the motherboard spec on a virtual machine thats spawned on the
cloud, for example Amazon EC2?

Cheers, Abhishek

On Mon, Jun 29, 2015 at 4:53 AM, Keunhong Lee <dlrmsghd at gmail.com> wrote:

> See your motherboard spec.
> For example, I'm using Intel 5930K with ASUS X99 Delux Motherboard (x99
> chipset).
> This site https://www.asus.com/us/Motherboards/X99DELUXE/specifications/
> tells that
> "Quad Channel Memory Architecture "
> which means that "-n 4" is the correct configuration for me.
>
> To fully use quad channel memory, I have to use 4 separated DRAM,
> installed on different memory slots of my motherboard.
>
> -n option optimizes memory bank access pattern for datastructures.
> Since most motherboards support dual or quad memory channel,
> -n 4 will work for most systems. (Only few motherboards support
> tri-channel memory)
>
> I hope that this information is useful to you.
> Keunhong.
>
>
>
> 2015-06-28 18:54 GMT+09:00 Abhishek Verma <abhishekv.verma at gmail.com>:
>
>> Hi,
>>
>> I am new to DPDK and i tried searching the archives in case this had been
>> discussed but couldnt find any references and hence this email:
>>
>> What is the significance of " -n NUM: Number of memory channels per
>> processor socket" which is passed as an EAL option? I have a virtual
>> machine (VM) spawned using VirtualBox and i am trying to use DPDK to get
>> faster access to packets there. I did lscpu, but that didnt give me
>> anything interesting that i could use here:
>>
>> abhishekV at VirtualBox:~/dpdk/dpdk-2.0.0/x86_64-native-linuxapp-gcc/app$
>> sudo
>> lscpu
>> [sudo] password for abhishekV:
>>
>> Architecture:          x86_64
>> CPU op-mode(s):        32-bit, 64-bit
>> Byte Order:            Little Endian
>> CPU(s):                2
>> On-line CPU(s) list:   0,1
>> Thread(s) per core:    1
>> Core(s) per socket:    2
>> Socket(s):             1
>> NUMA node(s):          1
>> Vendor ID:             GenuineIntel
>> CPU family:            6
>> Model:                 58
>> Stepping:              9
>> CPU MHz:               2594.017
>> BogoMIPS:              5188.03
>> L1d cache:             32K
>> L1d cache:             32K
>> L2d cache:             6144K
>> NUMA node0 CPU(s):     0,1
>> abhishekV at VirtualBox:~/dpdk/dpdk-2.0.0/x86_64-native-linuxapp-gcc/app$
>>
>> I understand that i have two cores and hence should use -c 1 (since i have
>> cores 0 and 1). However, i dont understand what to give as the "-n"
>> option.
>> Is it always 4?
>>
>> Thanks, Abhishek
>>
>
>