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From Peter Schuller <>
Subject Re: Performance tests using stress testing tool
Date Thu, 28 Apr 2011 17:21:37 GMT
> When I looked at the benchmark client machine, it was not under any stress
> in terms of disk or CPU.

Are you running with the python multiprocessor module available?
stress should print a warning if it's not. If it's not, you'd end up
with a threaded mode and due to Python's GIL you'd be bottlenecking on
CPU without actually using more than ~ 1 core on the machine.

> But test machines are connected through 10/100 mbps switch port (not
> gigabit). Can this be a bottleneck?

Maybe but seems not-so-likely unless you've turned up the column size.
Check if 'ifstat 1' if you're pushing lots of data.

Another possibility is that the writes are periodically blocking due
to compaction (and compaction is not yet parallel unless you're
running 0.8 betas). However this should show up in the stress client
by a period lack of progress; it shouldn't give you a smooth amount of
cpu usage over time.

/ Peter Schuller

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