Hi,
On Mon, 4 Jun 2012, Ants Aasma wrote:
> On Mon, Jun 4, 2012 at 7:44 PM, Merlin Moncure <mmoncure@gmail.com> wrote:
> I tried to keep it simple at first to find an answer to the question
> if it's even worth trying before expending large effort on it. If
> anyone with a multisocket machine would chip in, I'd love to know how
> this patch handles on larger machines. I think the most interesting
> workloads are read only loads with heavy buffer trashing but inside OS
> memory. Select only pgbench with 32MB shared_buffers was withín error
> margin, although slightly faster on my machine (Intel i2500K). The
> workload that I used to demonstrate gain was an aggregated index scan
> to minimise other overheads.
I've quickly tested your lockfree-getbuffer.patch patch with
the test case you provided and I barely see any improvement (2% at max)
https://docs.google.com/open?id=0B7koR68V2nM1QVBxWGpZdW4wd0U
tested with 24 core (48 ht cores, Xeon E7- 4807).
Although the tps vs number of threads looks weird....
Cheers, S
*****************************************************
Sergey E. Koposov, PhD, Research Associate
Institute of Astronomy, University of Cambridge
Madingley road, CB3 0HA, Cambridge, UK
Tel: +44-1223-337-551 Web: http://www.ast.cam.ac.uk/~koposov/