Perform scalar simple match lookup in AVX512 DPIF by reusing the simple
match lookup functions. The simple match lookup is placed in a separate
per packet loop before the batch miniflow extract call since miniflow
extract can be skipped when simple match is being used.
Unsuccessful lookup during simple match lookup means an upcall is
required because there is no suitable flow in the datapath. Fall back to
the scalar DPIF to do this upcall just like we already do later in
AVX512 DPIF when we have misses in the DPCLS.
Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
Tested-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: Sunil Pai G <sunil.pai.g@intel.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
As described in the bugzilla below, cpu_has_isa code may be compiled
with some AVX512 instructions in it, because cpu.c is built as part of
the libopenvswitchavx512.
This is a problem when this function (supposed to probe for AVX512
instructions availability) is invoked from generic OVS code, on older
CPUs that don't support them.
For the same reason, dpcls_subtable_avx512_gather_probe,
dp_netdev_input_outer_avx512_probe, mfex_avx512_probe and
mfex_avx512_vbmi_probe are potential runtime bombs and can't either be
built as part of libopenvswitchavx512.
Move cpu.c to be part of the "normal" libopenvswitch.
And move other helpers in generic OVS code.
Note:
- dpcls_subtable_avx512_gather_probe is split in two, because it also
needs to do its own magic,
- while moving those helpers, prefer direct calls to cpu_has_isa and
avoid cast to intermediate integer variables when a simple boolean
is enough,
Fixes: 352b6c7116cd ("dpif-lookup: add avx512 gather implementation.")
Fixes: abb807e27dd4 ("dpif-netdev: Add command to switch dpif implementation.")
Fixes: 250ceddcc2d0 ("dpif-netdev/mfex: Add AVX512 based optimized miniflow extract")
Fixes: b366fa2f4947 ("dpif-netdev: Call cpuid for x86 isa availability.")
Reported-at: https://bugzilla.redhat.com/2100393
Reported-by: Ales Musil <amusil@redhat.com>
Co-authored-by: Ales Musil <amusil@redhat.com>
Signed-off-by: Ales Musil <amusil@redhat.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Sunil Pai G <sunil.pai.g@intel.com>
Acked-by: Ales Musil <amusil@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
UINT64_C(1) is required in this bitshift since batch_size can be 32 and
1 << 32 overflows UINT32_C(1).
Fixes: ba0a2619ca0c ("dpif-netdev-avx512: Fix ubsan shift error in bitmasks.")
Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
The code changes here are to handle (1 << i) shifts where 'i' is the
packet index in the batch, and 1 << 31 is an overflow of the signed '1'.
Fixed by adding UINT32_C() around the 1 character, ensuring compiler knows
the 1 is unsigned (and 32-bits). Undefined Behaviour sanitizer is now happy
with the bit-shifts at runtime.
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
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>
DPIF AVX512 optimizations currently rely on DPDK availability while
they can be used without DPDK.
Besides, checking for availability of some isa only has to be done once
and won't change while a OVS process runs.
Resolve isa availability in constructors by using a simplified query
based on cpuid API that comes from the compiler.
Note: this also fixes the check on BMI2 availability: DPDK had a bug
for this isa, see https://git.dpdk.org/dpdk/commit/?id=aae3037ab1e0.
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Last RX queue, from which the packet got received, is already stored
in the PMD context. So, we can get the netdev from it without the
expensive hash map lookup.
In my V2V testing this patch improves performance in case HW offload
and experimental APIs are enabled by about 3%. That narrows down the
performance difference with the case with experimental API disabled
to about 0.5%, which is way within a margin of error for that setup.
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: Eli Britstein <elibr@nvidia.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
This commit adds a new counter to be displayed to the user when
requesting datapath packet statistics. It counts the number of
packets that are parsed and a miniflow built up from it by the
optimized miniflow extract parsers.
The ovs-appctl command "dpif-netdev/pmd-perf-show" now has an
extra entry indicating if the optimized MFEX was hit:
- MFEX Opt hits: 6786432 (100.0 %)
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Acked-by: Eelco Chaudron <echaudro@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>
It is possible for packets traversing the userspace datapath to match a
flow before hitting on EMC by using a mark ID provided by a NIC. Add a
PMD statistic for this hit.
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 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>
