Re: CVS commit: src/sys

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

On 30.07.2011 19:01, Christos Zoulas wrote:
> Module Name:  src
> Committed By: christos
> Date:         Sat Jul 30 17:01:05 UTC 2011
> 
> Modified Files:
>       src/sys/conf: files
>       src/sys/kern: init_main.c kern_lwp.c kern_synch.c
> Added Files:
>       src/sys/kern: subr_pserialize.c
>       src/sys/sys: pserialize.h
> 
> Log Message:
> Add an implementation of passive serialization as described in expired
> US patent 4809168. This is a reader / writer synchronization mechanism,
> designed for lock-less read operations.

Interesting! What would be the direct consumers of such an
implementation? For example, can pserialize be a drop-in replacement for
everything that is rwlock(9) based, or are they limitations?

(I am aware that passive serialization is not equivalent to RCU).

I remember reading articles mentioning how "wonderful" lockless
algorithms are, except in situation where the additional bus
locking/atomic ops involved did not really improve the situation in
highly concurrent systems (and could even make it worse).

-- 
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost