netdev - Re: [PATCH net-next] net: sched: refactor flower walk to iterate over idr

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Date:   Sat, 14 Jul 2018 18:50:28 +0300
From:   Or Gerlitz <gerlitz.or@...il.com>
To:     Vlad Buslov <vladbu@...lanox.com>
Cc:     Simon Horman <simon.horman@...ronome.com>,
        Linux Netdev List <netdev@...r.kernel.org>,
        David Miller <davem@...emloft.net>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>
Subject: Re: [PATCH net-next] net: sched: refactor flower walk to iterate over idr

On Tue, Jul 10, 2018 at 8:02 PM, Vlad Buslov <vladbu@...lanox.com> wrote:
>
> On Tue 10 Jul 2018 at 13:55, Simon Horman <simon.horman@...ronome.com> wrote:
>> On Mon, Jul 09, 2018 at 01:29:11PM +0300, Vlad Buslov wrote:
>>> Extend struct tcf_walker with additional 'cookie' field. It is intended to
>>> be used by classifier walk implementations to continue iteration directly
>>> from particular filter, instead of iterating 'skip' number of times.
>>>
>>> Change flower walk implementation to save filter handle in 'cookie'. Each
>>> time flower walk is called, it looks up filter with saved handle directly
>>> with idr, instead of iterating over filter linked list 'skip' number of
>>> times. This change improves complexity of dumping flower classifier from
>>> quadratic to linearithmic. (assuming idr lookup has logarithmic complexity)
>>>
>>> Reviewed-by: Jiri Pirko <jiri@...lanox.com>
>>> Signed-off-by: Vlad Buslov <vladbu@...lanox.com>
>>
>> Reported-by: Simon Horman <simon.horman@...ronome.com>
>>
>> Thanks, I'm very pleased to see this change. I would appreciate it if
>> we could have a little time to test its impact on performance
>> thoroughly.
>
> For me it reduced time needed to dump 5m flows to ~50 seconds. Not a
> very thorough benchmark, but performance improvement was so dramatic
> that I decided to not investigate further.


down from how long to 50 seconds??