Re: Linux 2.6.29

Kyle Moffett
2009-03-26T03:03:19Z

On Wed, Mar 25, 2009 at 10:51 PM, Jeff Garzik <jeff@garzik.org> wrote:
> Then you have just reinvented the transactional userspace API that people
> often want to replace POSIX API with.  Maybe one day they will succeed.
>
> But "POSIX API replacement" is an area never short of proposals... :)

Well, I think the goal is not to *replace* the POSIX API or even
provide "transactional" guarantees. The performance penalty for
atomic transactions is pretty high, and most programs (like GIT) don't
really give a damn, as they provide that on a higher level.

It's like the difference between a modern SMP system that supports
memory barriers and write snooping and one of the theoretical
"transactional memory" designs that have never caught on.

To be honest I think we could provide much better data consistency
guarantees and remove a lot of fsync() calls with just a basic
per-filesystem barrier() call.

Cheers,
Kyle Moffett