Re: [dpdk-dev] [PATCH 0/3] add new Double Word Key hash table

["Morten Brørup" <mb@smartsharesystems.com>]

> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Vladimir Medvedkin
> Sent: Monday, March 16, 2020 2:38 PM
> 
> Currently DPDK has a special implementation of a hash table for
> 4 byte keys which is called FBK hash. Unfortunately its main drawback
> is that it only supports 2 byte values.
> The new implementation called DWK (double word key) hash
> supports 8 byte values, which is enough to store a pointer.
> 
> It would also be nice to get feedback on whether to leave the old FBK
> and new DWK implementations, or whether to deprecate the old one?

<rant on>

Who comes up with these names?!?

FBK (Four Byte Key) and DWK (Double Word Key) is supposed to mean the same. Could you use 32 somewhere in the name instead, like in int32_t, instead of using a growing list of creative synonyms for the same thing? Pretty please, with a cherry on top!

And if the value size is fixed too, perhaps the name should also indicate the value size.

<rant off>

It's a shame we don't have C++ class templates available in DPDK...

In other news, Mellanox has sent an RFC for an "indexed memory pool" library [1] to conserve memory by using uintXX_t instead of pointers, so perhaps a variant of a 32 bit key hash library with 32 bit values (in addition to 16 bit values in FBK and 64 bit in DWK) would be nice combination with that library.

[1]: http://mails.dpdk.org/archives/dev/2019-October/147513.html


Med venlig hilsen / kind regards
- Morten Brørup