[lttng-dev] [RFC] Planning a release of the RCU lock-free hash table

[Stephen Hemminger]

On Fri, 17 Feb 2012 10:56:18 -0500
Mathieu Desnoyers <mathieu.desnoyers at efficios.com> wrote:

> Hello!
> 
> I wanted to ask around if the general feeling is that the API of the RCU
> lock-free hash table is stable enough to be pulled into the master
> branch of userspace rcu ? Are there any further changes to the API any
> of you would envision ?
> 
> Link to the current API:
> http://git.lttng.org/?p=userspace-rcu.git;a=blob;f=urcu/rculfhash.h;h=96dc5a023aa6d4958b24bf316269463ed114b62a;hb=refs/heads/urcu/ht-shrink
> 
> My personal thought is that after the restructuring, cleanup and fixes
> from Lai, and review from Paul and Stephen, things have been quiet for a
> few months, so it might be a good time to plan for a release.
> 
> Pointer to the rcu lock-free hash table branch:
> git://git.lttng.org/userspace-rcu.git branch: urcu/ht-shrink
> 
> It will be a _very_ nice addition to the userspace RCU library, as the
> uses of this lock-free hash table are many (think of routing, dns,
> parallel answer to network queries "pinned" to worker threads, etc..).
> This hash table is, IMHO, better than the Java lock-free hash table,
> mainly because the RCU lock-free hash table offers ordering guarantees
> over the modifications operations vs lookups and iteration.
> 

We have been using without problems for a couple months now.
Granted we haven't stressed it to extreme with lots of entries
in production (yet).