With iperf 2 you may be able to estimate this. Use -b <value> to set the
network load and -P to set the number of traffic threads. The assumption
is one traffic thread per core.
Bob
On Wed, Jul 11, 2018 at 12:02 PM, Kaushal Shriyan <kaushalshri...@gmail.com>
wrote:
>
>
> On Thu, Jul 5, 2018 at 8:01 PM Kaushal Shriyan <kaushalshri...@gmail.com>
> wrote:
>
>>
>>
>> On Thu, Jul 5, 2018 at 7:18 PM Jeffrey Lane <j...@canonical.com> wrote:
>>
>>> On Thu, Jul 5, 2018 at 5:07 AM, Sandro Bureca <sbur...@gmail.com> wrote:
>>> > For linux the following command can be used:
>>> >
>>> > cat /sys/class/net/eth0/statistics/rx_packets
>>> > cat /sys/class/net/eth0/statistics/tx_packets
>>>
>>> Or you could just do this:
>>>
>>> watch -n1 netstat -ni
>>>
>>> Also, if you're looking to see what cores are being hammered during
>>> processing:
>>>
>>> cat /proc/interrupts and look for lines matching your device (if
>>> present):
>>>
>>> 139: 37 0 0 0 0
>>> 0 4605821 0 IR-PCI-MSI 1048576-edge enp2s0
>>> 140: 0 2328 0 0 42268740
>>> 0 0 0 IR-PCI-MSI 1048577-edge enp2s0-TxRx-0
>>> 141: 0 0 243 0 0
>>> 0 0 1650980 IR-PCI-MSI 1048578-edge enp2s0-tx-1
>>> 142: 0 0 0 8748551 0
>>> 0 0 0 IR-PCI-MSI 1048579-edge enp2s0-tx-2
>>> 143: 0 0 0 0 189
>>> 1341058 0 0 IR-PCI-MSI 1048580-edge
>>> enp2s0-tx-3
>>>
>>> That's for an 8 core Skylake CPU on my desktop.
>>>
>>> Something like this will let you see it in 1 second intervals to see
>>> which core is getting the interrupts during network stuff:
>>>
>>> watch -n1 "cat /proc/interrupts | grep enp2s0"
>>>
>>> YMMV and all that.
>>>
>>
>>
>> Thanks Jeff and Sandro Bureca for the reply.
>>
>> [ec2-user@ip-172-31-11-0 ~]$ cat /sys/class/net/eth0/
>> statistics/rx_packets
>> 1520936 -> Does it mean 1520936 packets? if it reports 1 does it mean 1
>> packet?
>> [ec2-user@ip-172-31-11-0 ~]$ cat /sys/class/net/eth0/
>> statistics/tx_packets
>> 1135781 -> Does it mean 1135781 packets? if it reports 1 does it mean 1
>> packet?
>> [ec2-user@ip-172-31-11-0 ~]$
>>
>>
>> watch -n1 netstat -ni
>>
>> Every 1.0s: netstat -ni
>>
>> Thu Jul 5 14:26:03 2018
>>
>> Kernel Interface table
>> Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR
>> Flg
>> eth0 9001 1520859 0 0 0 1135669 0 0 0 BMRU
>> lo 65536 2898393 0 0 0 2898393 0 0 0 LRU
>>
>> watch -n1 "cat /proc/interrupts | grep eth0"
>> Every 1.0s: cat /proc/interrupts | grep eth0
>>
>> Thu Jul 5 14:25:29 2018
>>
>> 97: 161 0 0 0 1885854 0
>> 0 0 xen-pirq-msi-x eth0-TxRx-0
>> 98: 201 0 0 0 0 1613325
>> 0 0 xen-pirq-msi-x eth0-TxRx-1
>> 99: 54 0 0 0 0 0
>> 0 0 xen-pirq-msi-x eth0
>>
>> I look forward to hearing from you. How do i decide how many CPU cores i
>> need? Is there a thumb rule or any calculation to select AWS Instance for
>> example. Currently i have selected AWS t2.large instance type as per
>> https://aws.amazon.com/ec2/instance-types/ to set up Openswan IPsec VPN
>> tunnel without any basis. Correct me if i am wrong?
>>
>> I look forward to hearing from you
>>
>> Best Regards,
>>
>>
> Hi ,
>
> I will appreciate if someone can pitch in related to my earlier command
> output. Basically i am setting up AWS cloud instance viz how many CPU Cores
> to be selected to handle the network traffic. Is there a calculation to
> know how many cpu cores are needed for a specific network bandwidth?
>
> Best Regards,
>
> Kaushal
>
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