On 2/26/24 18:44, Ilya Maximets wrote:
> Currently, ovn-controller attempts to sync all the meters on each
> ofctrl_put() call. And the complexity of this logic is quadratic
> because for each desired meter we perform a full scan of all the
> rows in the Southbound Meter table in order to lookup a matching
> meter. This is very inefficient. In a setup with 25K meters this
> operation takes anywhere from 30 to 60 seconds to perform. All
> that time ovn-controller is blocked and doesn't process any updates.
> So, addition of new ports in such a setup becomes very slow.
>
> The meter lookup is performed by name and we have an index for it
> in the database schema. Might as well use it.
>
> Using the index for lookup reduces complexity to O(n * log n).
> And the time to process port addition on the same setup drops down
> to just 100 - 300 ms.
>
> We are still iterating over all the desired meters while they can
> probably be processed incrementally instead. But using an index
> is a simpler fix for now.
>
> Fixes: 885655e16e63 ("controller: reconfigure ovs meters for ovn meters")
> Fixes: 999e1adfb572 ("ovn: Support configuring meters through SB Meter
> table.")
> Reported-at: https://issues.redhat.com/browse/FDP-399
> Signed-off-by: Ilya Maximets <[email protected]>
> ---
>
> This is a "performance bug", so the decision to backport this or not
> is on maintainers. But it is severe enough, IMO.
>
> controller/ofctrl.c | 37 ++++++++++++++++++++++---------------
> controller/ofctrl.h | 2 +-
> controller/ovn-controller.c | 4 +++-
> 3 files changed, 26 insertions(+), 17 deletions(-)
Recheck-request: github-robot-_Build_and_Test
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