Open Stack

On Mon, 2014-01-06 at 11:17 -0800, Joe Gordon wrote:
> 
> 
> 
> On Mon, Jan 6, 2014 at 10:35 AM, Jay Pipes <jaypipes at gmail.com> wrote:
>         On Mon, 2014-01-06 at 09:56 -0800, Joe Gordon wrote:
>         
>         > What about it? Also those numbers are pretty old at this
>         point. I was
>         > thinking disable rootwrap and run full parallel tempest
>         against it.
>         
>         
>         I think that is a little overkill for what we're trying to do
>         here. We
>         are specifically talking about combining many utils.execute()
>         calls into
>         a single one. I think it's pretty obvious that the latter will
>         be better
>         performing than the first, unless you think that rootwrap has
>         no
>         performance overhead at all?
> 
> 
> mocking out rootwrap with straight sudo, is a very quick way to
> approximate the performance benefit of combining many utlils.execute()
> calls together (at least rootwrap wise).  Also  it would tell us how
> much of the problem is rootwrap induced and how much is other.

Yes, I understand that, which is what the article I linked earlier
showed?

% time sudo ip link >/dev/null
sudo ip link > /dev/null  0.00s user 0.00s system 43% cpu 0.009 total
% sudo time quantum-rootwrap /etc/quantum/rootwrap.conf ip link
> /dev/null
quantum-rootwrap /etc/quantum/rootwrap.conf ip link  > /dev/null  0.04s
user 0.02s system 87% cpu 0.059 total

A very tiny, non-scientific simple indication that rootwrap is around 6
times slower than a simple sudo call.

Best,
-jay