[dpdk-dev] Why DPDK is not using compressed TRIE for LPM6?

[Bruce Richardson]

On Sat, May 27, 2017 at 12:34:57AM +0530, Atul Shree wrote:
> Hello All,
> 
> I was doing some experiments related to LPM6 look up and I have added 20K
> entries in the table. By looking at the rte_lpm6_lookup() code I found an
> opportunity to compress the TRIE and there is a significant improvement
> after compression.
> 

Although I'm maintainer for LPM library, I'm not the original author of
the LPM6 code. However, I'll give my thoughts here. Adding Cristian D. on
CC as he was involved in the original implementation, IIRC.

> Here are my questions:
> Q1: Why DPDK is not doing the compression?

It's probably not a deliberate omission, more likely that nobody has
done it.

> Q2. In the worst case the table will behave like an uncompressed TRIE and
> in other cases, there is a scope of improvement. Is it worth doing?
> 

If there is improvement in the normal case, with the worst-case perf
being no worse, it sounds like it may be worth doing. Feel free to
submit patches for evaluation on the list.

Regards,
/Bruce