Re: First set of OSDL Shared Mem scalability results, some wierdness

Gaetano Mendola <mendola@bigfoot.com>

From: Gaetano Mendola <mendola@bigfoot.com>
To: Josh Berkus <josh@agliodbs.com>
Date: 2004-10-10T09:25:23Z
Lists: pgsql-hackers, pgsql-performance
Josh Berkus wrote:
> Folks,
> 
> I'm hoping that some of you can shed some light on this.
> 
> I've been trying to peg the "sweet spot" for shared memory using OSDL's 
> equipment.   With Jan's new ARC patch, I was expecting that the desired 
> amount of shared_buffers to be greatly increased.  This has not turned out to 
> be the case.
> 
> The first test series was using OSDL's DBT2 (OLTP) test, with 150 
> "warehouses".   All tests were run on a 4-way Pentium III 700mhz 3.8GB RAM 
> system hooked up to a rather high-end storage device (14 spindles).    Tests 
> were on PostgreSQL 8.0b3, Linux 2.6.7.

I'd like to see these tests running using the cpu affinity capability in order
to oblige a backend to not change CPU during his life, this could drastically
increase the cache hit.


Regards
Gaetano Mendola