Re: better atomics - v0.5

Andres Freund <andres@anarazel.de>

From: andres@anarazel.de (Andres Freund)
To: Josh Berkus <josh@agliodbs.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Peter Geoghegan <pg@heroku.com>, Pg Hackers <pgsql-hackers@postgresql.org>, Ants Aasma <ants@cybertec.at>
Date: 2014-06-25T17:45:31Z
Lists: pgsql-hackers
On 2014-06-25 10:39:53 -0700, Josh Berkus wrote:
> On 06/25/2014 10:14 AM, Andres Freund wrote:
> > Hi,
> > 
> > [sorry for the second copy Robert]
> > 
> > Attached is a new version of the atomic operations patch. Lots has
> > changed since the last post:
> 
> Is this at a state where we can performance-test it yet?

Well, this patch itself won't have a performance impact at all. It's
about proving the infrastructure to use atomic operations in further
patches in a compiler and platform independent way.
I'll repost a new version of the lwlocks patch (still fighting an issue
I introduced while rebasing ntop of Heikki's xlog scalability/lwlock
merger) soon. Addressing the review comments Amit has made since.

Greetings,

Andres Freund

-- 
 Andres Freund	                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


Commits

  1. Avoid the use of a separate spinlock to protect a LWLock's wait queue.

  2. Improve LWLock scalability.

  3. Reduce the number of semaphores used under --disable-spinlocks.

  4. Alter the configure script to fail immediately if the C compiler does not