There are cases where users might want simple forwarding or drop rules
for all packets received from a specific port, e.g ::
"in_port=1,actions=2"
"in_port=2,actions=IN_PORT"
"in_port=3,vlan_tci=0x1234/0x1fff,actions=drop"
"in_port=4,actions=push_vlan:0x8100,set_field:4196->vlan_vid,output:3"
There are also cases where complex OpenFlow rules can be simplified
down to datapath flows with very simple match criteria.
In theory, for very simple forwarding, OVS doesn't need to parse
packets at all in order to follow these rules. "Simple match" lookup
optimization is intended to speed up packet forwarding in these cases.
Design:
Due to various implementation constraints userspace datapath has
following flow fields always in exact match (i.e. it's required to
match at least these fields of a packet even if the OF rule doesn't
need that):
- recirc_id
- in_port
- packet_type
- dl_type
- vlan_tci (CFI + VID) - in most cases
- nw_frag - for ip packets
Not all of these fields are related to packet itself. We already
know the current 'recirc_id' and the 'in_port' before starting the
packet processing. It also seems safe to assume that we're working
with Ethernet packets. So, for the simple OF rule we need to match
only on 'dl_type', 'vlan_tci' and 'nw_frag'.
'in_port', 'dl_type', 'nw_frag' and 13 bits of 'vlan_tci' can be
combined in a single 64bit integer (mark) that can be used as a
hash in hash map. We are using only VID and CFI form the 'vlan_tci',
flows that need to match on PCP will not qualify for the optimization.
Workaround for matching on non-existence of vlan updated to match on
CFI and VID only in order to qualify for the optimization. CFI is
always set by OVS if vlan is present in a packet, so there is no need
to match on PCP in this case. 'nw_frag' takes 2 bits of PCP inside
the simple match mark.
New per-PMD flow table 'simple_match_table' introduced to store
simple match flows only. 'dp_netdev_flow_add' adds flow to the
usual 'flow_table' and to the 'simple_match_table' if the flow
meets following constraints:
- 'recirc_id' in flow match is 0.
- 'packet_type' in flow match is Ethernet.
- Flow wildcards contains only minimal set of non-wildcarded fields
(listed above).
If the number of flows for current 'in_port' in a regular 'flow_table'
equals number of flows for current 'in_port' in a 'simple_match_table',
we may use simple match optimization, because all the flows we have
are simple match flows. This means that we only need to parse
'dl_type', 'vlan_tci' and 'nw_frag' to perform packet matching.
Now we make the unique flow mark from the 'in_port', 'dl_type',
'nw_frag' and 'vlan_tci' and looking for it in the 'simple_match_table'.
On successful lookup we don't need to run full 'miniflow_extract()'.
Unsuccessful lookup technically means that we have no suitable flow
in the datapath and upcall will be required. So, in this case EMC and
SMC lookups are disabled. We may optimize this path in the future by
bypassing the dpcls lookup too.
Performance improvement of this solution on a 'simple match' flows
should be comparable with partial HW offloading, because it parses same
packet fields and uses similar flow lookup scheme.
However, unlike partial HW offloading, it works for all port types
including virtual ones.
Performance results when compared to EMC:
Test setup:
virtio-user OVS virtio-user
Testpmd1 ------------> pmd1 ------------> Testpmd2
(txonly) x<------ pmd2 <------------ (mac swap)
Single stream of 64byte packets. Actions:
in_port=vhost0,actions=vhost1
in_port=vhost1,actions=vhost0
Stats collected from pmd1 and pmd2, so there are 2 scenarios:
Virt-to-Virt : Testpmd1 ------> pmd1 ------> Testpmd2.
Virt-to-NoCopy : Testpmd2 ------> pmd2 --->x Testpmd1.
Here the packet sent from pmd2 to Testpmd1 is always dropped, because
the virtqueue is full since Testpmd1 is in txonly mode and doesn't
receive any packets. This should be closer to the performance of a
VM-to-Phy scenario.
Test performed on machine with Intel Xeon CPU E5-2690 v4 @ 2.60GHz.
Table below represents improvement in throughput when compared to EMC.
+----------------+------------------------+------------------------+
| | Default (-g -O2) | "-Ofast -march=native" |
| Scenario +------------+-----------+------------+-----------+
| | GCC | Clang | GCC | Clang |
+----------------+------------+-----------+------------+-----------+
| Virt-to-Virt | +18.9% | +25.5% | +10.8% | +16.7% |
| Virt-to-NoCopy | +24.3% | +33.7% | +14.9% | +22.0% |
+----------------+------------+-----------+------------+-----------+
For Phy-to-Phy case performance improvement should be even higher, but
it's not the main use-case for this functionality. Performance
difference for the non-simple flows is within a margin of error.
Acked-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Users complained that per rxq pmd usage was confusing: summing those
values per pmd would never reach 100% even if increasing traffic load
beyond pmd capacity.
This is because the dpif-netdev/pmd-rxq-show command only reports "pure"
rxq cycles while some cycles are used in the pmd mainloop and adds up to
the total pmd load.
dpif-netdev/pmd-stats-show does report per pmd load usage.
This load is measured since the last dpif-netdev/pmd-stats-clear call.
On the other hand, the per rxq pmd usage reflects the pmd load on a 10s
sliding window which makes it non trivial to correlate.
Gather per pmd busy cycles with the same periodicity and report the
difference as overhead in dpif-netdev/pmd-rxq-show so that we have all
info in a single command.
Example:
$ ovs-appctl dpif-netdev/pmd-rxq-show
pmd thread numa_id 1 core_id 3:
isolated : true
port: dpdk0 queue-id: 0 (enabled) pmd usage: 90 %
overhead: 4 %
pmd thread numa_id 1 core_id 5:
isolated : false
port: vhost0 queue-id: 0 (enabled) pmd usage: 0 %
port: vhost1 queue-id: 0 (enabled) pmd usage: 93 %
port: vhost2 queue-id: 0 (enabled) pmd usage: 0 %
port: vhost6 queue-id: 0 (enabled) pmd usage: 0 %
overhead: 6 %
pmd thread numa_id 1 core_id 31:
isolated : true
port: dpdk1 queue-id: 0 (enabled) pmd usage: 86 %
overhead: 4 %
pmd thread numa_id 1 core_id 33:
isolated : false
port: vhost3 queue-id: 0 (enabled) pmd usage: 0 %
port: vhost4 queue-id: 0 (enabled) pmd usage: 0 %
port: vhost5 queue-id: 0 (enabled) pmd usage: 92 %
port: vhost7 queue-id: 0 (enabled) pmd usage: 0 %
overhead: 7 %
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Kevin Traynor <ktraynor@redhat.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
This patch introduces the MFEX function pointers which allows
the user to switch between different miniflow extract implementations
which are provided by the OVS based on optimized ISA CPU.
The user can query for the available minflow extract variants available
for that CPU by following commands:
$ovs-appctl dpif-netdev/miniflow-parser-get
Similarly an user can set the miniflow implementation by the following
command :
$ ovs-appctl dpif-netdev/miniflow-parser-set name
This allows for more performance and flexibility to the user to choose
the miniflow implementation according to the needs.
Signed-off-by: Kumar Amber <kumar.amber@intel.com>
Co-authored-by: Harry van Haaren <harry.van.haaren@intel.com>
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
This commit adds a new command to allow the user to switch
the active DPIF implementation at runtime. A probe function
is executed before switching the DPIF implementation, to ensure
the CPU is capable of running the ISA required. For example, the
below code will switch to the AVX512 enabled DPIF assuming
that the runtime CPU is capable of running AVX512 instructions:
$ ovs-appctl dpif-netdev/dpif-impl-set dpif_avx512
A new configuration flag is added to allow selection of the
default DPIF. This is useful for running the unit-tests against
the available DPIF implementations, without modifying each unit test.
The design of the testing & validation for ISA optimized DPIF
implementations is based around the work already upstream for DPCLS.
Note however that a DPCLS lookup has no state or side-effects, allowing
the auto-validator implementation to perform multiple lookups and
provide consistent statistic counters.
The DPIF component does have state, so running two implementations in
parallel and comparing output is not a valid testing method, as there
are changes in DPIF statistic counters (side effects). As a result, the
DPIF is tested directly against the unit-tests.
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Co-authored-by: Cian Ferriter <cian.ferriter@intel.com>
Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
This commit adds the AVX512 implementation of DPIF functionality,
specifically the dp_netdev_input_outer_avx512 function. This function
only handles outer (no re-circulations), and is optimized to use the
AVX512 ISA for packet batching and other DPIF work.
Sparse is not able to handle the AVX512 intrinsics, causing compile
time failures, so it is disabled for this file.
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Co-authored-by: Cian Ferriter <cian.ferriter@intel.com>
Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
Co-authored-by: Kumar Amber <kumar.amber@intel.com>
Signed-off-by: Kumar Amber <kumar.amber@intel.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
This commit adds a function pointer to the pmd thread data structure,
giving the pmd thread flexibility in its dpif-input function choice.
This allows choosing of the implementation based on ISA capabilities
of the runtime CPU, leading to optimizations and higher performance.
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Co-authored-by: Cian Ferriter <cian.ferriter@intel.com>
Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
Split the very large file dpif-netdev.c and the datastructures
it contains into multiple header files. Each header file is
responsible for the datastructures of that component.
This logical split allows better reuse and modularity of the code,
and reduces the very large file dpif-netdev.c to be more managable.
Due to dependencies between components, it is not possible to
move component in smaller granularities than this patch.
To explain the dependencies better, eg:
DPCLS has no deps (from dpif-netdev.c file)
FLOW depends on DPCLS (struct dpcls_rule)
DFC depends on DPCLS (netdev_flow_key) and FLOW (netdev_flow_key)
THREAD depends on DFC (struct dfc_cache)
DFC_PROC depends on THREAD (struct pmd_thread)
DPCLS lookup.h/c require only DPCLS
DPCLS implementations require only dpif-netdev-lookup.h.
- This change was made in 2.12 release with function pointers
- This commit only refactors the name to "private-dpcls.h"
netdev_flow_key_equal_mf() is renamed to emc_flow_key_equal_mf().
Rename functions specific to dpcls from netdev_* namespace to the
dpcls_* namespace, as they are only used by dpcls code.
'inline' is added to the dp_netdev_flow_hash() when it is moved
definition to fix a compiler error.
One valid checkpatch issue with the use of the
EMC_FOR_EACH_POS_WITH_HASH() macro was fixed.
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Co-authored-by: Cian Ferriter <cian.ferriter@intel.com>
Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
