Hi,
I suspect a CPU bottleneck in one of our PostgreSQL servers but not sure how to confirm the suspect.
It's a DELL Box running CentOS 5.4 with 64GB RAM and 16 XEON E7430 2.13 GHz processors. vmstat r column "run queue" usually indicates values higher than 2 and less than 5 but "Load Average" values from top, sar -q and other commands show always values less than 1.
Should not these values be higher than 16 on a box with 16 processors to confirm a CPU constraint?
Thank you in advance!
On Sat, Feb 09, 2013 at 04:24:19PM -0200, Carlos Henrique Reimer wrote:
processors. vmstat r column "run queue" usually indicates values higher than 2 and less than 5 but "Load Average" values from top, sar -q and other commands show always values less than 1.
Should not these values be higher than 16 on a box with 16 processors to confirm a CPU constraint?
If you have single-threaded processes then that process could chew up 100% of a single core but not be able to run any faster. The load average would only be 1.
Load average is a poor measure; look at %idle on each core. If you see one core with 0% idle then something is maxed out.
Hi,
All 16 core show always %idle greater than 95% (mpstat -P ALL).
So can I assume there is no CPU constraint in this box?
Thank you!
On Sat, Feb 9, 2013 at 4:37 PM, Stephen Harris lists@spuddy.org wrote:
On Sat, Feb 09, 2013 at 04:24:19PM -0200, Carlos Henrique Reimer wrote:
processors. vmstat r column "run queue" usually indicates values higher than 2 and less than 5 but "Load Average" values from top, sar -q and
other
commands show always values less than 1.
Should not these values be higher than 16 on a box with 16 processors to confirm a CPU constraint?
If you have single-threaded processes then that process could chew up 100% of a single core but not be able to run any faster. The load average would only be 1.
Load average is a poor measure; look at %idle on each core. If you see one core with 0% idle then something is maxed out.
--
rgds Stephen _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
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Carlos Henrique Reimer -
Stephen Harris