[dpdk-dev] DPDK qos support for 40G port

Dumitrescu, Cristian cristian.dumitrescu at intel.com
Fri Aug 4 11:57:11 CEST 2017


Hi Kevin,

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Kevin Yan
> Sent: Friday, August 4, 2017 2:55 AM
> To: dev at dpdk.org
> Subject: [dpdk-dev] DPDK qos support for 40G port
> 
> Hi,
>                 I have  a question about dpdk qos feature, in rte_sched.h,

<snip>...

>                 rate is type of uint32_t, but if physical port rate is 40G bit/s, which is
> 5G byte/s, 5G already exceed the max value of uint32_t, so I doult that 40G is
> not supported by dpdk qos lib, or any error of my understanding?
> 

Yes, your understanding is correct, currently the port rate in bytes per second needs to be represented as 32-bit number.

So, we can currently do single port with 10GbE and 25GbE rate, but not single port of 40GbE or 100GbE. Please note that we can do 40GbE as 4 ports of 10GbE each, which is a very common configuration for 40GbE.

This limitation is not trivial to remove, i.e. more code is needed to remove this limitation than just changing the rate data type to uint64_t.

Thanks for your feedback. Good to know that we should upgrade this library to support 40GbE rates sooner rather than later.

>                 Thanks and waiting for your reply!
> 
> 
> BRs,
> Kevin
> 

Regards,
Cristian



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