The preprocessor comparison string to check AVX512 capabilities are
lengthy and effecting user readability. Simpify this by aliasing the checks.
Suggested-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Sunil Pai G <sunil.pai.g@intel.com>
Acked-by: Cian Ferriter <cian.ferriter@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>
Checking for each of the required AVX512 ISA separately will allow the
compiler to generate some AVX512 code where there is some support in the
compiler rather than only generating all AVX512 code when all of it is
supported or no AVX512 code at all.
For example, in GCC 4.9 where there is just support for AVX512F, this
patch will allow building the AVX512 DPIF.
Another example, in GCC 5 and 6, most AVX512 code can be generated, just
without AVX512VPOPCNTDQ support.
Signed-off-by: Cian Ferriter <cian.ferriter@intel.com>
Acked-by: Sunil Pai G <sunil.pai.g@intel.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Modified the dplcs info-get command output to include
the count for different dpcls implementations.
$ovs-appctl dpif-netdev/subtable-lookup-info-get
Available dpcls implementations:
autovalidator (Use count: 1, Priority: 5)
generic (Use count: 0, Priority: 1)
avx512_gather (Use count: 0, Priority: 3)
Test case to verify changes:
1061: PMD - dpcls configuration ok
Signed-off-by: Kumar Amber <kumar.amber@intel.com>
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Co-authored-by: Harry van Haaren <harry.van.haaren@intel.com>
Co-authored-by: Eelco Chaudron <echaudro@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
This commit adds an AVX-512 dpcls lookup implementation.
It uses the AVX-512 SIMD ISA to perform multiple miniflow
operations in parallel.
To run this implementation, the "avx512f" and "bmi2" ISAs are
required. These ISA checks are performed at runtime while
probing the subtable implementation. If a CPU does not provide
both "avx512f" and "bmi2", then this code does not execute.
The avx512 code is built as a separate static library, with added
CFLAGS to enable the required ISA features. By building only this
static library with avx512 enabled, it is ensured that the main OVS
core library is *not* using avx512, and that OVS continues to run
as before on CPUs that do not support avx512.
The approach taken in this implementation is to use the
gather instruction to access the packet miniflow, allowing
any miniflow blocks to be loaded into an AVX-512 register.
This maximizes the usefulness of the register, and hence this
implementation handles any subtable with up to miniflow 8 bits.
Note that specialization of these avx512 lookup routines
still provides performance value, as the hashing of the
resulting data is performed in scalar code, and compile-time
loop unrolling occurs when specialized to miniflow bits.
This commit checks at configure time if the assembling in use
has a known bug in assembling AVX512 code. If this bug is present,
all AVX512 code is disabled. Checking the version string of the binutils
or assembler is not a good method to detect the issue, as back ported
fixes would not be reflected.
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
This commit refactors the existing dpif subtable function pointer
infrastructure, and implements an autovalidator component.
The refactoring of the existing dpcls subtable lookup function
handling, making it more generic, and cleaning up how to enable
more implementations in future.
In order to ensure all implementations provide identical results,
the autovalidator is added. The autovalidator itself implements
the subtable lookup function prototype, but internally iterates
over all other available implementations. The end result is that
testing of each implementation becomes automatic, when the auto-
validator implementation is selected.
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
