| Message ID | 20191002084103.12138-1-idosch@idosch.org |
|---|---|
| Headers | show |
| Series | Simplify IPv4 route offload API | expand |
Wed, Oct 02, 2019 at 10:40:48AM CEST, idosch@idosch.org wrote: >From: Ido Schimmel <idosch@mellanox.com> > >Today, whenever an IPv4 route is added or deleted a notification is sent >in the FIB notification chain and it is up to offload drivers to decide >if the route should be programmed to the hardware or not. This is not an >easy task as in hardware routes are keyed by {prefix, prefix length, >table id}, whereas the kernel can store multiple such routes that only >differ in metric / TOS / nexthop info. > >This series makes sure that only routes that are actually used in the >data path are notified to offload drivers. This greatly simplifies the >work these drivers need to do, as they are now only concerned with >programming the hardware and do not need to replicate the IPv4 route >insertion logic and store multiple identical routes. > >The route that is notified is the first FIB alias in the FIB node with >the given {prefix, prefix length, table ID}. In case the route is >deleted and there is another route with the same key, a replace >notification is emitted. Otherwise, a delete notification is emitted. > >The above means that in the case of multiple routes with the same key, >but different TOS, only the route with the highest TOS is notified. >While the kernel can route a packet based on its TOS, this is not >supported by any hardware devices I'm familiar with. Moreover, this is >not supported by IPv6 nor by BIRD/FRR from what I could see. Offload >drivers should therefore use the presence of a non-zero TOS as an >indication to trap packets matching the route and let the kernel route >them instead. mlxsw has been doing it for the past two years. > >The series also adds an "in hardware" indication to routes, in addition I think this might be a separate patchset. I mean patch "ipv4: Replace route in list before notifying" and above. >to the offload indication we already have on nexthops today. Besides >being long overdue, the reason this is done in this series is that it >makes it possible to easily test the new FIB notification API over >netdevsim. > >To ensure there is no degradation in route insertion rates, I used >Vincent Bernat's script [1][2] from [3] to inject 500,000 routes from an >MRT dump from a router with a full view. On a system with Intel(R) >Xeon(R) CPU D-1527 @ 2.20GHz I measured 8.184 seconds, averaged over 10 >runs and saw no degradation compared to net-next from today. > >Patchset overview: >Patches #1-#7 introduce the new FIB notifications >Patches #8-#9 convert listeners to make use of the new notifications >Patches #10-#14 add "in hardware" indication for IPv4 routes, including >a dummy FIB offload implementation in netdevsim >Patch #15 adds a selftest for the new FIB notifications API over >netdevsim > >The series is based on Jiri's "devlink: allow devlink instances to >change network namespace" series [4]. The patches can be found here [5] >and patched iproute2 with the "in hardware" indication can be found here >[6]. > >IPv6 is next on my TODO list. > >[1] https://github.com/vincentbernat/network-lab/blob/master/common/helpers/lab-routes-ipvX/insert-from-bgp >[2] https://gist.github.com/idosch/2eb96efe50eb5234d205e964f0814859 >[3] https://vincent.bernat.ch/en/blog/2017-ipv4-route-lookup-linux >[4] https://patchwork.ozlabs.org/cover/1162295/ >[5] https://github.com/idosch/linux/tree/fib-notifier >[6] https://github.com/idosch/iproute2/tree/fib-notifier > >Ido Schimmel (15): > ipv4: Add temporary events to the FIB notification chain > ipv4: Notify route after insertion to the routing table > ipv4: Notify route if replacing currently offloaded one > ipv4: Notify newly added route if should be offloaded > ipv4: Handle route deletion notification > ipv4: Handle route deletion notification during flush > ipv4: Only Replay routes of interest to new listeners > mlxsw: spectrum_router: Start using new IPv4 route notifications > ipv4: Remove old route notifications and convert listeners > ipv4: Replace route in list before notifying > ipv4: Encapsulate function arguments in a struct > ipv4: Add "in hardware" indication to routes > mlxsw: spectrum_router: Mark routes as "in hardware" > netdevsim: fib: Mark routes as "in hardware" > selftests: netdevsim: Add test for route offload API > > .../net/ethernet/mellanox/mlx5/core/lag_mp.c | 4 - > .../ethernet/mellanox/mlxsw/spectrum_router.c | 152 ++----- > drivers/net/ethernet/rocker/rocker_main.c | 4 +- > drivers/net/netdevsim/fib.c | 263 ++++++++++- > include/net/ip_fib.h | 5 + > include/uapi/linux/rtnetlink.h | 1 + > net/ipv4/fib_lookup.h | 18 +- > net/ipv4/fib_semantics.c | 30 +- > net/ipv4/fib_trie.c | 223 ++++++++-- > net/ipv4/route.c | 12 +- > .../drivers/net/netdevsim/fib_notifier.sh | 411 ++++++++++++++++++ > 11 files changed, 938 insertions(+), 185 deletions(-) > create mode 100755 tools/testing/selftests/drivers/net/netdevsim/fib_notifier.sh > >-- >2.21.0 >
On Wed, Oct 02, 2019 at 08:17:59PM +0200, Jiri Pirko wrote: > Wed, Oct 02, 2019 at 10:40:48AM CEST, idosch@idosch.org wrote: > >From: Ido Schimmel <idosch@mellanox.com> > > > >Today, whenever an IPv4 route is added or deleted a notification is sent > >in the FIB notification chain and it is up to offload drivers to decide > >if the route should be programmed to the hardware or not. This is not an > >easy task as in hardware routes are keyed by {prefix, prefix length, > >table id}, whereas the kernel can store multiple such routes that only > >differ in metric / TOS / nexthop info. > > > >This series makes sure that only routes that are actually used in the > >data path are notified to offload drivers. This greatly simplifies the > >work these drivers need to do, as they are now only concerned with > >programming the hardware and do not need to replicate the IPv4 route > >insertion logic and store multiple identical routes. > > > >The route that is notified is the first FIB alias in the FIB node with > >the given {prefix, prefix length, table ID}. In case the route is > >deleted and there is another route with the same key, a replace > >notification is emitted. Otherwise, a delete notification is emitted. > > > >The above means that in the case of multiple routes with the same key, > >but different TOS, only the route with the highest TOS is notified. > >While the kernel can route a packet based on its TOS, this is not > >supported by any hardware devices I'm familiar with. Moreover, this is > >not supported by IPv6 nor by BIRD/FRR from what I could see. Offload > >drivers should therefore use the presence of a non-zero TOS as an > >indication to trap packets matching the route and let the kernel route > >them instead. mlxsw has been doing it for the past two years. > > > >The series also adds an "in hardware" indication to routes, in addition > > I think this might be a separate patchset. I mean patch "ipv4: Replace > route in list before notifying" and above. OK. I mainly wanted to have it together in order to submit the tests with the patchset itself. I can split it into two.
From: Ido Schimmel <idosch@mellanox.com> Today, whenever an IPv4 route is added or deleted a notification is sent in the FIB notification chain and it is up to offload drivers to decide if the route should be programmed to the hardware or not. This is not an easy task as in hardware routes are keyed by {prefix, prefix length, table id}, whereas the kernel can store multiple such routes that only differ in metric / TOS / nexthop info. This series makes sure that only routes that are actually used in the data path are notified to offload drivers. This greatly simplifies the work these drivers need to do, as they are now only concerned with programming the hardware and do not need to replicate the IPv4 route insertion logic and store multiple identical routes. The route that is notified is the first FIB alias in the FIB node with the given {prefix, prefix length, table ID}. In case the route is deleted and there is another route with the same key, a replace notification is emitted. Otherwise, a delete notification is emitted. The above means that in the case of multiple routes with the same key, but different TOS, only the route with the highest TOS is notified. While the kernel can route a packet based on its TOS, this is not supported by any hardware devices I'm familiar with. Moreover, this is not supported by IPv6 nor by BIRD/FRR from what I could see. Offload drivers should therefore use the presence of a non-zero TOS as an indication to trap packets matching the route and let the kernel route them instead. mlxsw has been doing it for the past two years. The series also adds an "in hardware" indication to routes, in addition to the offload indication we already have on nexthops today. Besides being long overdue, the reason this is done in this series is that it makes it possible to easily test the new FIB notification API over netdevsim. To ensure there is no degradation in route insertion rates, I used Vincent Bernat's script [1][2] from [3] to inject 500,000 routes from an MRT dump from a router with a full view. On a system with Intel(R) Xeon(R) CPU D-1527 @ 2.20GHz I measured 8.184 seconds, averaged over 10 runs and saw no degradation compared to net-next from today. Patchset overview: Patches #1-#7 introduce the new FIB notifications Patches #8-#9 convert listeners to make use of the new notifications Patches #10-#14 add "in hardware" indication for IPv4 routes, including a dummy FIB offload implementation in netdevsim Patch #15 adds a selftest for the new FIB notifications API over netdevsim The series is based on Jiri's "devlink: allow devlink instances to change network namespace" series [4]. The patches can be found here [5] and patched iproute2 with the "in hardware" indication can be found here [6]. IPv6 is next on my TODO list. [1] https://github.com/vincentbernat/network-lab/blob/master/common/helpers/lab-routes-ipvX/insert-from-bgp [2] https://gist.github.com/idosch/2eb96efe50eb5234d205e964f0814859 [3] https://vincent.bernat.ch/en/blog/2017-ipv4-route-lookup-linux [4] https://patchwork.ozlabs.org/cover/1162295/ [5] https://github.com/idosch/linux/tree/fib-notifier [6] https://github.com/idosch/iproute2/tree/fib-notifier Ido Schimmel (15): ipv4: Add temporary events to the FIB notification chain ipv4: Notify route after insertion to the routing table ipv4: Notify route if replacing currently offloaded one ipv4: Notify newly added route if should be offloaded ipv4: Handle route deletion notification ipv4: Handle route deletion notification during flush ipv4: Only Replay routes of interest to new listeners mlxsw: spectrum_router: Start using new IPv4 route notifications ipv4: Remove old route notifications and convert listeners ipv4: Replace route in list before notifying ipv4: Encapsulate function arguments in a struct ipv4: Add "in hardware" indication to routes mlxsw: spectrum_router: Mark routes as "in hardware" netdevsim: fib: Mark routes as "in hardware" selftests: netdevsim: Add test for route offload API .../net/ethernet/mellanox/mlx5/core/lag_mp.c | 4 - .../ethernet/mellanox/mlxsw/spectrum_router.c | 152 ++----- drivers/net/ethernet/rocker/rocker_main.c | 4 +- drivers/net/netdevsim/fib.c | 263 ++++++++++- include/net/ip_fib.h | 5 + include/uapi/linux/rtnetlink.h | 1 + net/ipv4/fib_lookup.h | 18 +- net/ipv4/fib_semantics.c | 30 +- net/ipv4/fib_trie.c | 223 ++++++++-- net/ipv4/route.c | 12 +- .../drivers/net/netdevsim/fib_notifier.sh | 411 ++++++++++++++++++ 11 files changed, 938 insertions(+), 185 deletions(-) create mode 100755 tools/testing/selftests/drivers/net/netdevsim/fib_notifier.sh