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

Ananyev, Konstantin konstantin.ananyev at intel.com
Sat Sep 23 12:37:22 CEST 2017



> -----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





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