Bill,
In order to manifest the context switch problem you will definitely
require clients to be set to more than one in pgbench. It only occurs
when 2 or more backends need access to shared memory.
If you want help backpatching Gavin's patch I'll be glad to do it for
you, but you do need a
On Tue, Oct 05, 2004 at 09:47:36AM -0700, Josh Berkus wrote:
As long as you're on x86, scaling outward is the way to go. If you want to
continue to scale upwards, ask Andrew Sullivan about his experiences running
PostgreSQL on big IBM boxes. But if you consider an quad-Opteron server
Alan Stange wrote:
Here's a few numbers from the Opteron 250. If I get some time I'll
post a more comprehensive comparison including some other systems.
The system is a Sun v20z. Dual Opteron 250, 2.4Ghz, Linux 2.6, 8 GB
memory. I did a compile and install of pg 8.0 beta 3. I created a
On Thu, Oct 07, 2004 at 11:48:41AM -0400, Bill Montgomery wrote:
Alan Stange wrote:
The same test on a Dell PowerEdge 1750, Dual Xeon 3.2 GHz, 512k cache,
HT on, Linux 2.4.21-20.ELsmp (RHEL 3), 4GB memory, pg 7.4.5:
Far less performance that the Dual Opterons with a low number of
Bill Montgomery wrote:
Alan Stange wrote:
Here's a few numbers from the Opteron 250. If I get some time I'll
post a more comprehensive comparison including some other systems.
The system is a Sun v20z. Dual Opteron 250, 2.4Ghz, Linux 2.6, 8 GB
memory. I did a compile and install of pg 8.0
Michael Adler wrote:
On Thu, Oct 07, 2004 at 11:48:41AM -0400, Bill Montgomery wrote:
Alan Stange wrote:
The same test on a Dell PowerEdge 1750, Dual Xeon 3.2 GHz, 512k cache,
HT on, Linux 2.4.21-20.ELsmp (RHEL 3), 4GB memory, pg 7.4.5:
Far less performance that the Dual Opterons with a low
Greg Stark wrote:
Alan Stange [EMAIL PROTECTED] writes:
A few quick random observations on the Xeon v. Opteron comparison:
- running a dual Xeon with hyperthreading turned on really isn't the same as
having a quad cpu system. I haven't seen postgresql specific benchmarks, but
the general case
Josh Berkus wrote:
I'd be thrilled to test it too, if for no other reason that to determine
whether what I'm experiencing really is the CS problem.
Hmmm ... Gavin's patch is built against 8.0, and any version of the patch
would require linux 2.6, probably 2.6.7 minimum. Can you test on
Hmmm...
I may be mistaken (I think last time I read about optimization params was in
7.3 docs), but doesn't RPC 1 mean that random read is faster than
sequential read? In your case, do you really think reading randomly is 4x
faster than reading sequentially? Doesn't seem to make sense, even with
Alan Stange wrote:
A few quick random observations on the Xeon v. Opteron comparison:
[SNIP]
I don't care to go into the whole debate of Xeon v. Opteron here. We
also have a lot of dual Xeon systems. In every comparison I've done with
our codes, the dual Opteron clearly outperforms the dual
Here's a few numbers from the Opteron 250. If I get some time I'll post
a more comprehensive comparison including some other systems.
The system is a Sun v20z. Dual Opteron 250, 2.4Ghz, Linux 2.6, 8 GB
memory. I did a compile and install of pg 8.0 beta 3. I created a
data base on a tmpfs
Bill,
I realize the excessive-context-switching-on-xeon issue has been
discussed at length in the past, but I wanted to follow up and verify my
conclusion from those discussions:
First off, the good news: Gavin Sherry and OSDL may have made some progress
on this. We'll be testing as soon
Thanks for the helpful response.
Josh Berkus wrote:
First off, the good news: Gavin Sherry and OSDL may have made some
progress
on this. We'll be testing as soon as OSDL gets the Scalable Test Platform
running again. If you have the CS problem (which I don't think you do, see
below) and a
Bill Montgomery wrote:
All,
I realize the excessive-context-switching-on-xeon issue has been
discussed at length in the past, but I wanted to follow up and verify my
conclusion from those discussions:
On a 2-way or 4-way Xeon box, there is no way to avoid excessive
(30,000-60,000 per second)
Bill,
I'd be thrilled to test it too, if for no other reason that to determine
whether what I'm experiencing really is the CS problem.
Hmmm ... Gavin's patch is built against 8.0, and any version of the patch
would require linux 2.6, probably 2.6.7 minimum. Can you test on that linux
A few quick random observations on the Xeon v. Opteron comparison:
- running a dual Xeon with hyperthreading turned on really isn't the
same as having a quad cpu system. I haven't seen postgresql specific
benchmarks, but the general case has been that HT is a benefit in a few
particular work
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