Hi All, We have recently hit some performance issues with nova-network. It turns out the root cause of this was we do roughly 20 rootwrapped shell commands, many inside of global locks. (https://bugs.launchpad.net/oslo/+bug/1199433)
It turns out starting python itself, has a fairly significant overhead when compared to the run time of many of the binary commands we execute. For example: $ time python -c "print 'test'" test real 0m0.023s user 0m0.016s sys 0m0.004s $ time ip a <...> real 0m0.003s user 0m0.000s sys 0m0.000s While we have removed the extra overhead of using entry points, we are now hitting the overhead of just shelling out to python. While there are many possible ways to reduce this issue, such as reducing the number of rootwrapped calls and making locks finer grain, I think its worth exploring alternates to the current rootwrap model. Any ideas? I am sending this email out to get the discussion started. best, Joe Gordon
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