Re: [PATCH net-next v12 4/4] net sched actions: add time filter for action dumping

[Jiri Pirko <jiri@resnulli.us>]

Sun, Jul 30, 2017 at 07:24:52PM CEST, jhs@mojatatu.com wrote:
>From: Jamal Hadi Salim <jhs@mojatatu.com>
>
>This patch adds support for filtering based on time since last used.
>When we are dumping a large number of actions it is useful to
>have the option of filtering based on when the action was last
>used to reduce the amount of data crossing to user space.
>
>With this patch the user space app sets the TCA_ROOT_TIME_DELTA
>attribute with the value in milliseconds with "time of interest
>since now".  The kernel converts this to jiffies and does the
>filtering comparison matching entries that have seen activity
>since then and returns them to user space.
>Old kernels and old tc continue to work in legacy mode since
>they dont specify this attribute.
>
>Some example (we have 400 actions bound to 400 filters); at
>installation time. Using updated when tc setting the time of
>interest to 120 seconds earlier (we see 400 actions):
>prompt$ hackedtc actions ls action gact since 120000| grep index | wc -l
>400
>
>go get some coffee and wait for > 120 seconds and try again:
>
>prompt$ hackedtc actions ls action gact since 120000 | grep index | wc -l
>0
>
>Lets see a filter bound to one of these actions:
>....
>filter pref 10 u32
>filter pref 10 u32 fh 800: ht divisor 1
>filter pref 10 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:10  (rule hit 2 success 1)
>  match 7f000002/ffffffff at 12 (success 1 )
>    action order 1: gact action pass
>     random type none pass val 0
>     index 23 ref 2 bind 1 installed 1145 sec used 802 sec
>    Action statistics:
>    Sent 84 bytes 1 pkt (dropped 0, overlimits 0 requeues 0)
>    backlog 0b 0p requeues 0
>....
>
>that coffee took long, no? It was good.
>
>Now lets ping -c 1 127.0.0.2, then run the actions again:
>prompt$ hackedtc actions ls action gact since 120 | grep index | wc -l
>1
>
>More details please:
>prompt$ hackedtc -s actions ls action gact since 120000
>
>    action order 0: gact action pass
>     random type none pass val 0
>     index 23 ref 2 bind 1 installed 1270 sec used 30 sec
>    Action statistics:
>    Sent 168 bytes 2 pkt (dropped 0, overlimits 0 requeues 0)
>    backlog 0b 0p requeues 0
>
>And the filter?
>
>filter pref 10 u32
>filter pref 10 u32 fh 800: ht divisor 1
>filter pref 10 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:10  (rule hit 4 success 2)
>  match 7f000002/ffffffff at 12 (success 2 )
>    action order 1: gact action pass
>     random type none pass val 0
>     index 23 ref 2 bind 1 installed 1324 sec used 84 sec
>    Action statistics:
>    Sent 168 bytes 2 pkt (dropped 0, overlimits 0 requeues 0)
>    backlog 0b 0p requeues 0
>
>Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>

Reviewed-by: Jiri Pirko <jiri@mellanox.com>