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/*
* Copyright (c) 2020 Intel Corporation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include <errno.h>
#include "dpif-netdev-lookup.h"
#include "cpu.h"
#include "openvswitch/vlog.h"
VLOG_DEFINE_THIS_MODULE(dpif_netdev_lookup);
#define DPCLS_IMPL_AVX512_CHECK (__x86_64__ && HAVE_AVX512F \
&& HAVE_LD_AVX512_GOOD && HAVE_AVX512BW && __SSE4_2__)
#if DPCLS_IMPL_AVX512_CHECK
static dpcls_subtable_lookup_func
dpcls_subtable_avx512_gather_probe(uint32_t u0_bits, uint32_t u1_bits)
{
if (!cpu_has_isa(OVS_CPU_ISA_X86_AVX512F)
|| !cpu_has_isa(OVS_CPU_ISA_X86_BMI2)) {
return NULL;
}
return dpcls_subtable_avx512_gather_probe__(u0_bits, u1_bits,
cpu_has_isa(OVS_CPU_ISA_X86_VPOPCNTDQ));
}
#endif
/* Actual list of implementations goes here */
static struct dpcls_subtable_lookup_info_t subtable_lookups[] = {
/* The autovalidator implementation will not be used by default, it must
* be enabled at compile time to be the default lookup implementation. The
* user may enable it at runtime using the normal "prio-set" command if
* desired. The compile time default switch is here to enable all unit
* tests to transparently run with the autovalidator.
*/
#ifdef DPCLS_AUTOVALIDATOR_DEFAULT
{ .prio = 255,
#else
{ .prio = 0,
#endif
.probe = dpcls_subtable_autovalidator_probe,
.name = "autovalidator",
.usage_cnt = ATOMIC_COUNT_INIT(0), },
/* The default scalar C code implementation. */
{ .prio = 1,
.probe = dpcls_subtable_generic_probe,
.name = "generic",
.usage_cnt = ATOMIC_COUNT_INIT(0), },
#if DPCLS_IMPL_AVX512_CHECK
/* Only available on x86_64 bit builds with SSE 4.2 used for OVS core. */
{ .prio = 0,
.probe = dpcls_subtable_avx512_gather_probe,
.name = "avx512_gather",
.usage_cnt = ATOMIC_COUNT_INIT(0), },
#else
/* Disabling AVX512 at compile time, as compile time requirements not met.
* This could be due to a number of reasons:
* 1) core OVS is not compiled with SSE4.2 instruction set.
* The SSE42 instructions are required to use CRC32 ISA for high-
* performance hashing. Consider ./configure of OVS with -msse42 (or
* newer) to enable CRC32 hashing and higher performance.
* 2) The assembler in binutils versions 2.30 and 2.31 has bugs in AVX512
* assembly. Compile time probes check for this assembler issue, and
* disable the HAVE_LD_AVX512_GOOD check if an issue is detected.
* Please upgrade binutils, or backport this binutils fix commit:
* 2069ccaf8dc28ea699bd901fdd35d90613e4402a
*/
#endif
};
int
dpcls_subtable_lookup_info_get(struct dpcls_subtable_lookup_info_t **out_ptr)
{
if (out_ptr == NULL) {
return -1;
}
*out_ptr = subtable_lookups;
return ARRAY_SIZE(subtable_lookups);
}
/* sets the priority of the lookup function with "name". */
int
dpcls_subtable_set_prio(const char *name, uint8_t priority)
{
for (int i = 0; i < ARRAY_SIZE(subtable_lookups); i++) {
if (strcmp(name, subtable_lookups[i].name) == 0) {
subtable_lookups[i].prio = priority;
VLOG_INFO("Subtable function '%s' set priority to %d\n",
name, priority);
return 0;
}
}
VLOG_WARN("Subtable function '%s' not found, failed to set priority\n",
name);
return -EINVAL;
}
dpcls_subtable_lookup_func
dpcls_subtable_get_best_impl(uint32_t u0_bit_count, uint32_t u1_bit_count,
struct dpcls_subtable_lookup_info_t **info)
{
struct dpcls_subtable_lookup_info_t *best_info = NULL;
dpcls_subtable_lookup_func best_func = NULL;
int prio = -1;
/* Iter over each subtable impl, and get highest priority one. */
for (int i = 0; i < ARRAY_SIZE(subtable_lookups); i++) {
struct dpcls_subtable_lookup_info_t *impl_info = &subtable_lookups[i];
dpcls_subtable_lookup_func probed_func;
if (impl_info->prio <= prio) {
continue;
}
probed_func = subtable_lookups[i].probe(u0_bit_count,
u1_bit_count);
if (!probed_func) {
continue;
}
best_func = probed_func;
best_info = impl_info;
prio = impl_info->prio;
}
/* Programming error - we must always return a valid func ptr. */
ovs_assert(best_func != NULL && best_info != NULL);
VLOG_DBG("Subtable lookup function '%s' with units (%d,%d), priority %d\n",
best_info->name, u0_bit_count, u1_bit_count, prio);
if (info) {
*info = best_info;
}
return best_func;
}
void
dpcls_info_inc_usage(struct dpcls_subtable_lookup_info_t *info)
{
if (info) {
atomic_count_inc(&info->usage_cnt);
}
}
void
dpcls_info_dec_usage(struct dpcls_subtable_lookup_info_t *info)
{
if (info) {
atomic_count_dec(&info->usage_cnt);
}
}
void
dpcls_impl_print_stats(struct ds *reply)
{
struct dpcls_subtable_lookup_info_t *lookup_funcs = NULL;
int count = dpcls_subtable_lookup_info_get(&lookup_funcs);
/* Add all DPCLS functions to reply string. */
ds_put_cstr(reply, "Available dpcls implementations:\n");
for (int i = 0; i < count; i++) {
ds_put_format(reply, " %s (Use count: %d, Priority: %d",
lookup_funcs[i].name,
atomic_count_get(&lookup_funcs[i].usage_cnt),
lookup_funcs[i].prio);
if (ds_last(reply) == ' ') {
ds_put_cstr(reply, "none");
}
ds_put_cstr(reply, ")\n");
}
}
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