[dpdk-dev] eventdev DSW question

[Mattias Rönnblom]

On 2019-12-06 01:26, Venky Venkatesh wrote:
> I see that the provision in 18.11 eventdev DSW for maximum number of queues
> is
> 
> #define DSW_MAX_QUEUES (16)
> 
> 
> 
>     1. If the number of queues needed is to be increased to 7 bits (i.e.
>     128) is there any issue (correctness, scale, performance) other than
>     increased data structure size?

No.

>     2. I see that it is only used in the following structs:
>        - struct dsw_evdev: struct dsw_queue queues[DSW_MAX_QUEUES];
>        sizeof(struct dsw_queue) ~ DSW_MAX_FLOWS. So the total increase
>        contribution here is (128-16)*DSW_MAX_FLOWS from about 0.5MB to 4MB
>        - struct dsw_port: uint64_t queue_enqueued[DSW_MAX_QUEUES],
> queue_dequeued[DSW_MAX_QUEUES];
>        This increase is negligible (a few KB at most across all dsw_ports)

On x86_64, the size of the dsw_evdev-struct is increased by ~32 kB per 
queue added.

>     3. So is it enough if I changed the above define? (In other words I hope
>     there are no other hidden/implicit dependencies on the current value 16
>     elsewhere in the code). Also I suppose the only way is to directly change
>     this in the code, rite?
> 

Yes, and yes.

The original reason for having that define was that I thought 16 queues 
would be enough for anyone. As so many in the past that has utter such 
statements, I might well have been wrong.

/M