[dpdk-dev] [PATCH v5] net/i40e: fix mirror rule reset when port is stopped

[Dai, Wei]

> -----Original Message-----
> From: Ananyev, Konstantin
> Sent: Saturday, September 23, 2017 6:37 PM
> To: Wu, Jingjing <jingjing.wu at intel.com>; Dai, Wei <wei.dai at intel.com>;
> Xing, Beilei <beilei.xing at intel.com>
> Cc: dev at dpdk.org; stable at dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v5] net/i40e: fix mirror rule reset when port
> is stopped
> 
> 
> 
> > -----Original Message-----
> > From: Wu, Jingjing
> > Sent: Saturday, September 23, 2017 3:27 AM
> > To: Ananyev, Konstantin <konstantin.ananyev at intel.com>; Dai, Wei
> > <wei.dai at intel.com>; Xing, Beilei <beilei.xing at intel.com>
> > Cc: dev at dpdk.org; stable at dpdk.org
> > Subject: RE: [dpdk-dev] [PATCH v5] net/i40e: fix mirror rule reset
> > when port is stopped
> >
> >
> >
> > > -----Original Message-----
> > > From: Ananyev, Konstantin
> > > Sent: Thursday, September 21, 2017 6:46 AM
> > > To: Dai, Wei <wei.dai at intel.com>; Wu, Jingjing
> > > <jingjing.wu at intel.com>; Xing, Beilei <beilei.xing at intel.com>
> > > Cc: dev at dpdk.org; stable at dpdk.org
> > > Subject: RE: [dpdk-dev] [PATCH v5] net/i40e: fix mirror rule reset
> > > when port is stopped
> > >
> > > Hi Wei,
> > >
> > > >
> > > > Hi, Konstantin
> > > >
> > > > Without this patch, when a port is stopped, all mirror SW resource
> > > > are cleared but HW
> > > settings are still there.
> > > > And once the port is started again, creating mirror rule may fail
> > > > due to remain HW
> > > settings.
> > > >
> > > > There is a testpmd use case which can show why this patch is needed.
> > > > 1. bind PF to igb_uio
> > > > #/root/dpdk-devbind.py -b igb_uio 0000:08:00.0 2. create 2 VFs
> > > > #echo 2 > /sys/bus/pci/devices/0000\:08\:00.0/max_vfs
> > > > 3. launch testpmd with PF, and set port mirror configuration
> > > > #./x86_64-native-linuxapp-gcc/app/testpmd -c 3 -n 4 -- -i  Testpmd
> > > > > set port 0 mirror-rule 0 pool-mirror-up 0x1 dst-pool 1 on
> > > > Testpmd > quit 4. relaunch testpmd with PF, and set port mirror as
> > > > the same configuration #./x86_64-native-linuxapp-gcc/app/testpmd
> > > > -c 3 -n 4 -- -i  Testpmd > set port 0 mirror-rule 0 pool-mirror-up
> > > > 0x1 dst-pool 1 on  I40e_mirror_rule_set( ): failed to add mirror
> > > > rule: ret = -53, aq_err = 13.
> > > >  Mirror rule add error: (Function not implemented)
> > > >
> > > > When testpmd is quitted, rte_eth_dev_stop( ) and then
> rte_eth_dev_close( ) are called.
> > > > In these function, i40e_dev_stop( ) and i40e_dev_close( ) is called.
> > > > And i40e_dev_stop is also called by i40e_dev_close( ).
> > > >
> > > > Without this patch, the error in second running of testpmd always
> happen.
> > > > This patch can address this error.
> > >
> > > Thanks for explanation.
> > > Though it seems that the patch while fixing the issue might
> > > introduce some
> > > inconsistences:
> > > 1. right now for i40e: dev_stop(port); dev_start(port) would keep
> > > existing HW mirror rule working.
> > >    With your patch is not any more.
> > > 2. What about ixgbe? Do we also need to change its behavior?
> > >     As I can see right now ixgbe doesn't reset any mirror rules at
> dev_stop().
> > >    Would it be reset automatically, or do we need to update ixgbe PMD
> too?
> > >
> > > About #1 - if we'll decide that this is a desired behavior that
> > > dev_stop() voids all mirror rules, then at least we probably need to
> update the documentation.
> > > As alternative - at dev_stop() we can reset only actual HW rule, but
> > > keep SW configuration intact, and restore them at dev_start().
> > > I personally think second option is a bit better - as it preserves
> > > existing behavior, and probably more convenient for the user.
> >
> > Yes, you reminded me the mirror is to VF. The mirror rule should be
> > kept or at least be restored when device start again..
> > Because the dev_stop should only stop the pf interface, but not affect
> > VF. It looks like we don't delete the VEB we dev_stop.
> > The reset behavior may need to be done in dev_close, but not in dev_stop.
> 
> if we can move that code into dev_close() , then indeed might be a better
> approach.
> 
> >
> > >
> > > About the patch itself, why just not:
> > > while ((p_mirror = TAILQ_FIRST(&pf->mirror_list)))
> > >     i40e_mirror_rule_reset(dev, p_mirror->index);
> > >
> > Wei's v1 patch is doing like that. But I commented it to change it.
> > Because i40e_mirror_rule_reset is doing a search in the list which is not
> necessary.
> 
> Yes, but it is a control path, so need to be extra quick  here.
> As a plus - avoid code duplication and easier to control/maintain it.
> Konstantin
> 
Thanks to Konstantin and Jingjing for all of your suggestion.
I will work out v6 patch to put all these mirror reset operations in dev_close( ).
As to ixgbe, same scheme will be tried and tested.