Hi From: Ananyev, Konstantin [mailto:konstantin.anan...@intel.com] > Hi lads, > > > > > Hi Matan, > > > > On Fri, Jan 19, 2018 at 01:35:10PM +0000, Matan Azrad wrote: > > > Hi Konstantin > > > > > > From: Ananyev, Konstantin, Friday, January 19, 2018 3:09 PM > > > > > -----Original Message----- > > > > > From: Matan Azrad [mailto:ma...@mellanox.com] > > > > > Sent: Friday, January 19, 2018 12:52 PM > > > > > To: Ananyev, Konstantin <konstantin.anan...@intel.com>; Thomas > > > > > Monjalon <tho...@monjalon.net>; Gaetan Rivet > > > > <gaetan.ri...@6wind.com>; > > > > > Wu, Jingjing <jingjing...@intel.com> > > > > > Cc: dev@dpdk.org; Neil Horman <nhor...@tuxdriver.com>; > > > > > Richardson, Bruce <bruce.richard...@intel.com> > > > > > Subject: RE: [PATCH v3 7/7] app/testpmd: adjust ethdev port > > > > > ownership > > > > > > > > > > Hi Konstantin > > > > > > > > > > From: Ananyev, Konstantin, Friday, January 19, 2018 2:38 PM > > > > > > To: Matan Azrad <ma...@mellanox.com>; Thomas Monjalon > > > > > > <tho...@monjalon.net>; Gaetan Rivet > <gaetan.ri...@6wind.com>; > > > > Wu, > > > > > > Jingjing <jingjing...@intel.com> > > > > > > Cc: dev@dpdk.org; Neil Horman <nhor...@tuxdriver.com>; > > > > > > Richardson, Bruce <bruce.richard...@intel.com> > > > > > > Subject: RE: [PATCH v3 7/7] app/testpmd: adjust ethdev port > > > > > > ownership > > > > > > > > > > > > Hi Matan, > > > > > > > > > > > > > -----Original Message----- > > > > > > > From: Matan Azrad [mailto:ma...@mellanox.com] > > > > > > > Sent: Thursday, January 18, 2018 4:35 PM > > > > > > > To: Thomas Monjalon <tho...@monjalon.net>; Gaetan Rivet > > > > > > > <gaetan.ri...@6wind.com>; Wu, Jingjing > > > > > > > <jingjing...@intel.com> > > > > > > > Cc: dev@dpdk.org; Neil Horman <nhor...@tuxdriver.com>; > > > > Richardson, > > > > > > > Bruce <bruce.richard...@intel.com>; Ananyev, Konstantin > > > > > > > <konstantin.anan...@intel.com> > > > > > > > Subject: [PATCH v3 7/7] app/testpmd: adjust ethdev port > > > > > > > ownership > > > > > > > > > > > > > > Testpmd should not use ethdev ports which are managed by > > > > > > > other DPDK entities. > > > > > > > > > > > > > > Set Testpmd ownership to each port which is not used by > > > > > > > other entity and prevent any usage of ethdev ports which are > > > > > > > not owned by > > > > Testpmd. > > > > > > > > > > > > > > Signed-off-by: Matan Azrad <ma...@mellanox.com> > > > > > > > --- > > > > > > > app/test-pmd/cmdline.c | 89 +++++++++++++++++++---------- > ------- > > > > ---- > > > > > > ----- > > > > > > > app/test-pmd/cmdline_flow.c | 2 +- > > > > > > > app/test-pmd/config.c | 37 ++++++++++--------- > > > > > > > app/test-pmd/parameters.c | 4 +- > > > > > > > app/test-pmd/testpmd.c | 63 ++++++++++++++++++++-------- > ---- > > > > > > > app/test-pmd/testpmd.h | 3 ++ > > > > > > > 6 files changed, 103 insertions(+), 95 deletions(-) > > > > > > > > > > > > > > diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c > > > > > > > index > > > > > > > 31919ba..6199c64 100644 > > > > > > > --- a/app/test-pmd/cmdline.c > > > > > > > +++ b/app/test-pmd/cmdline.c > > > > > > > @@ -1394,7 +1394,7 @@ struct cmd_config_speed_all { > > > > > > > &link_speed) < 0) > > > > > > > return; > > > > > > > > > > > > > > - RTE_ETH_FOREACH_DEV(pid) { > > > > > > > + RTE_ETH_FOREACH_DEV_OWNED_BY(pid, my_owner.id) { > > > > > > > > > > > > Why do we need all these changes? > > > > > > As I understand you changed definition of > > > > > > RTE_ETH_FOREACH_DEV(), so no testpmd should work ok default > (no_owner case). > > > > > > Am I missing something here? > > > > > > > > > > Now, After Gaetan suggestion RTE_ETH_FOREACH_DEV(pid) will > > > > > iterate > > > > over all valid and ownerless ports. > > > > > > > > Yes. > > > > > > > > > Here Testpmd wants to iterate over its owned ports. > > > > > > > > Why? Why it can't just iterate over all valid and ownerless ports? > > > > As I understand it would be enough to fix current problems and > > > > would allow us to avoid any changes in testmpd (which I think is a good > thing). > > > > > > Yes, I understand that this big change is very daunted, But I think > > > the current a lot of bugs in testpmd(regarding port ownership) even > > > more > > daunted. > > > > > > Look, > > > Testpmd initiates some of its internal databases depends on specific > > > port iteration, In some time someone may take ownership of Testpmd > ports and testpmd will continue to touch them. > > But if someone will take the ownership (assign new owner_id) that port will > not appear in RTE_ETH_FOREACH_DEV() any more. >
Yes, but testpmd sometimes depends on previous iteration using internal database. So it uses internal database that was updated by old iteration. > > > > > > > If I look back on the fail-safe, its sole purpose is to have seamless > > hotplug with existing applications. > > > > Port ownership is a genericization of some functions introduced by the > > fail-safe, that could structure DPDK further. It should allow > > applications to have a seamless integration with subsystems using port > > ownership. Without this, port ownership cannot be used. > > > > Testpmd should be fixed, but follow the most common design patterns of > > DPDK applications. Going with port ownership seems like a paradigm > > shift. > > > > > In addition > > > Using the old iterator in some places in testpmd will cause a race for > > > run- > time new ports(can be created by failsafe or any hotplug code): > > > - testpmd finds an ownerless port(just now created) by the old > > > iterator and start traffic there, > > > - failsafe takes ownership of this new port and start traffic there. > > > Problem! > > Could you shed a bit more light here - it would be race condition between > whom and whom? Sure. > As I remember in testpmd all control ops are done within one thread (main > lcore). But other dpdk entity can use another thread, for example: Failsafe uses the host thread(using alarm callback) to create a new port and to take ownership of a port. The race: Testpmd iterates over all ports by the master thread. Failsafe takes ownership of a port by the host thread and start using it. => The two dpdk entities may use the device at same time! Obeying the new ownership rules can prevent all these races. > The only way to attach/detach port with it - invoke testpmd CLI > "attach/detach" port. > > Konstantin > > > > > Testpmd does not handle detection of new port. If it did, testing > > fail-safe with it would be wrong. > > > > At startup, RTE_ETH_FOREACH_DEV already fixed the issue of registering > > DEFERRED ports. There are still remaining issues regarding this, but I > > think they should be fixed. The architecture does not need to be > > completely moved to port ownership. > > > > If anything, this should serve as a test for your API with common > > applications. I think you'd prefer to know and debug with testpmd > > instead of firing up VPP or something like that to determine what went > > wrong with using the fail-safe. > > > > > > > > In addition > > > As a good example for well-done application (free from ownership > > > bugs) I tried here to adjust Tespmd to the new rules and BTW to fix > > > a > > lot of bugs. > > > > Testpmd has too much cruft, it won't ever be a good example of a > > well-done application. > > > > If you want to demonstrate ownership, I think you should start an > > example application demonstrating race conditions and their mitigation. > > > > I think that would be interesting for many DPDK users. > > > > > > > > > > > So actually applications which are not aware to the port ownership > > > still are exposed to races, but if there use the old iterator(with > > > the new > > change) the amount of races decreases. > > > > > > Thanks, Matan. > > > > Konstantin > > > > > > > > > > > > > > I added to Testpmd ability to take an ownership of ports as the > > > > > new ownership and synchronization rules suggested, Since Tespmd > > > > > is a DPDK entity which wants that no one will touch its owned > > > > > ports, It must allocate > > > > an unique ID, set owner for its ports (see in main function) and > > > > recognizes them by its owner ID. > > > > > > > > > > > Konstantin > > > > > > > > > > Regards, > > -- > > Gaëtan Rivet > > 6WIND
