two different threads polls the same port, different queues, why the throughput is the same

two different threads polls the same port, different queues, why the throughput is the same

[张伟]

Hi all, 


I have two threads process the packets with different ways. thread A (core 0) is very heavy, thread B (core 1) is very light.   If I just run each of them, their throughput is huge different with small packet. Thread A polls queue 0 of port 0, thread B polls queue 1 of port 0. If I run them at the same time, why thread A and thread B get same throughput. This makes me very confused. Does anyone have the same experience or know some possible reasons?  


Thanks, 
wei

Re: two different threads polls the same port, different queues, why the throughput is the same

[Kyle Larose]

On Mon, Nov 14, 2016 at 2:28 PM, 张伟 <zhangwqh@126.com> wrote:
> Hi all,
>
>
> I have two threads process the packets with different ways. thread A (core 0) is very heavy, thread B (core 1) is very light.   If I just run each of them, their throughput is huge different with small packet. Thread A polls queue 0 of port 0, thread B polls queue 1 of port 0. If I run them at the same time, why thread A and thread B get same throughput. This makes me very confused. Does anyone have the same experience or know some possible reasons?
>

Can you give some examples with numbers? My first thought is that
maybe the two threads are contending for the same physical core. You
don't have any locking/critical sections, do you?
>
> Thanks,
> wei

Re: two different threads polls the same port, different queues, why the throughput is the same

[张伟]

I do not have any lock/critical sections in my code. 
I have logs to print out the core id, src port, dst port and queue id.  worker 0 runs on core 1,  run macswap very light, the throughput is 4.5Mpps. worker 1 runs on core2, is a load balancer heavy, the throughput is also 4.5Mpps. This does not make sense at all. 

***thread core_id=1, src_port=0, dst_port=0, rx_queue_id=0, tx_queue_id=0

***thread core_id=2, src_port=0, dst_port=0, rx_queue_id=1, tx_queue_id=1

Core 0: Running stat thread

worker_id=0, core_id=1, pkt_rate=4418972

worker_id=1, core_id=2, pkt_rate=4419808

worker_id=0, core_id=1, pkt_rate=4631684

worker_id=1, core_id=2, pkt_rate=4632928
 







At 2016-11-14 14:13:25, "Kyle Larose" <eomereadig@gmail.com> wrote:
>On Mon, Nov 14, 2016 at 2:28 PM, 张伟 <zhangwqh@126.com> wrote:
>> Hi all,
>>
>>
>> I have two threads process the packets with different ways. thread A (core 0) is very heavy, thread B (core 1) is very light.   If I just run each of them, their throughput is huge different with small packet. Thread A polls queue 0 of port 0, thread B polls queue 1 of port 0. If I run them at the same time, why thread A and thread B get same throughput. This makes me very confused. Does anyone have the same experience or know some possible reasons?
>>
>
>Can you give some examples with numbers? My first thought is that
>maybe the two threads are contending for the same physical core. You
>don't have any locking/critical sections, do you?
>>
>> Thanks,
>> wei