Re: [dpdk-dev] [PATCH 0/3] New Thread Safe Hash Library

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 18 Sep 2014 11:34:28 +0100
Pablo de Lara <pablo.de.lara.guarch@intel.com> wrote:

> This is an alternative hash implementation to the existing hash library. 
> This patch set provides a thread safe hash implementation, it allows users 
> to use multiple readers/writers working on a same hash table.
> Main differences between the previous and the new implementation are:
> 
> - Multiple readers/writers can work on the same hash table, 
>   whereas in the previous implementation writers could not work 
>   on the table at the same time readers do.
> - Previous implementation returned an index to a table after a lookup. 
>   This implementation returns 8-byte integers or pointers to external data.
> - Maximum entries to be looked up in bursts is 64, instead of 16.
> - Maximum key length has being increased to 128, instead of a maximum of 64.
> 
> Basic implementation:
> 
> - A sparse table containing buckets (64-byte long) with hashes,
>   most of which are empty, and indexes to the second table.
> - A compact table containing keys for final matching, 
>   plus data associated to them.
> 
> 

There is already a cool resizeable hash table as part of userspace
RCU which is thread safe.