Yeah, I'm sure binding each process to a CPU would be a significant
help. Something I've always wanted to quantify but haven't made time for...
Mark
Luke Lonergan wrote:
One of our customers noticed that there were a high number of NUMA cache
misses on a quad core opteron system running Bizgres MPP resulting in about
a 15% performance hit. We use a process-based parallelization approach and
we can guess that there's context switching due to the high degree of
pipeline parallelism in our executions plans. Each context switch likely
switches a process away from the CPU with local memory, resulting in the
NUMA cache misses.
The answer for us is to bind each process to a CPU. Might that help in
running DBT-2?
- Luke
On 10/10/06 9:40 AM, "Mark Wong" <[EMAIL PROTECTED]> wrote:
Luke Lonergan wrote:
+1
Mark, can you quantify the impact of not running with IRQ balancing enabled?
Whoops, look like performance was due more to enabling the
--enable-thread-safe flag.
IRQ balancing on : 7086.75
http://dbt.osdl.org/dbt/dbt2dev/results/dev4-015/158/
IRQ balancing off: 7057.90
http://dbt.osdl.org/dbt/dbt2dev/results/dev4-015/163/
The interrupt charts look completely different. There's too much stuff
on the chart to determine what interrupts are from what though. :( It
needs to be redone per processor (as opposed to per interrupt per
processor) to be more useful in determining if one processor is
overloaded due to interrupts.
http://dbt.osdl.org/dbt/dbt2dev/results/dev4-015/158/report/sar/sar-intr.png
http://dbt.osdl.org/dbt/dbt2dev/results/dev4-015/163/report/sar/sar-intr.png
But the sum of all the interrupts handled are close between tests so it
seems clear no single processor was overloaded:
http://dbt.osdl.org/dbt/dbt2dev/results/dev4-015/158/report/sar/sar-intr_s.png
http://dbt.osdl.org/dbt/dbt2dev/results/dev4-015/163/report/sar/sar-intr_s.png
Mark
---------------------------(end of broadcast)---------------------------
TIP 6: explain analyze is your friend
