The study function runs all the available implementations of miniflow_extract and makes a choice whose hitmask has maximum hits and sets the mfex to that function.
Study can be run at runtime using the following command: $ ovs-appctl dpif-netdev/miniflow-parser-set study Signed-off-by: Kumar Amber <kumar.am...@intel.com> Co-authored-by: Harry van Haaren <harry.van.haa...@intel.com> Signed-off-by: Harry van Haaren <harry.van.haa...@intel.com> --- lib/automake.mk | 1 + lib/dpif-netdev-extract-study.c | 119 ++++++++++++++++++++++++++++++ lib/dpif-netdev-private-extract.c | 5 ++ lib/dpif-netdev-private-extract.h | 14 +++- 4 files changed, 138 insertions(+), 1 deletion(-) create mode 100644 lib/dpif-netdev-extract-study.c diff --git a/lib/automake.mk b/lib/automake.mk index 6657b9ae5..3080bb04a 100644 --- a/lib/automake.mk +++ b/lib/automake.mk @@ -114,6 +114,7 @@ lib_libopenvswitch_la_SOURCES = \ lib/dpif-netdev.c \ lib/dpif-netdev.h \ lib/dpif-netdev-private-dfc.c \ + lib/dpif-netdev-extract-study.c \ lib/dpif-netdev-private-dfc.h \ lib/dpif-netdev-private-dpcls.h \ lib/dpif-netdev-private-dpif.c \ diff --git a/lib/dpif-netdev-extract-study.c b/lib/dpif-netdev-extract-study.c new file mode 100644 index 000000000..d063d040c --- /dev/null +++ b/lib/dpif-netdev-extract-study.c @@ -0,0 +1,119 @@ +/* + * Copyright (c) 2021 Intel. + * + * 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 <stdint.h> +#include <string.h> + +#include "dpif-netdev-private-extract.h" +#include "dpif-netdev-private-thread.h" +#include "openvswitch/vlog.h" +#include "ovs-thread.h" + +VLOG_DEFINE_THIS_MODULE(dpif_mfex_extract_study); + +/* Max size of packets to be compared. */ +#define MFEX_MAX_COUNT (128) + +/* This value is the threshold for the amount of packets that + * must hit on the optimized miniflow extract before it will be + * accepted and used in the datapath after the study phase. */ +#define MFEX_MIN_HIT_COUNT_FOR_USE (MFEX_MAX_COUNT / 2) + +/* Struct to hold miniflow study stats. */ +struct study_stats { + uint32_t pkt_count; + uint32_t impl_hitcount[MFEX_IMPLS_MAX_SIZE]; +}; + +/* Define per thread data to hold the study stats. */ +DEFINE_PER_THREAD_MALLOCED_DATA(struct study_stats *, study_stats); + +/* Allocate per thread PMD pointer space for study_stats. */ +static inline struct study_stats * +get_study_stats(void) +{ + struct study_stats *stats = study_stats_get(); + if (OVS_UNLIKELY(!stats)) { + stats = xzalloc(sizeof *stats); + study_stats_set_unsafe(stats); + } + return stats; +} + +uint32_t +mfex_study_traffic(struct dp_packet_batch *packets, + struct netdev_flow_key *keys, + uint32_t keys_size, odp_port_t in_port, + void *pmd_handle) +{ + uint32_t hitmask = 0; + uint32_t mask = 0; + struct dp_netdev_pmd_thread *pmd = pmd_handle; + struct dpif_miniflow_extract_impl *miniflow_funcs; + uint32_t impl_count = dpif_miniflow_extract_info_get(&miniflow_funcs); + struct study_stats *stats = get_study_stats(); + + /* Run traffic optimized miniflow_extract to collect the hitmask + * to be compared after certain packets have been hit to choose + * the best miniflow_extract version for that traffic. */ + for (int i = MFEX_IMPL_START_IDX; i < impl_count; i++) { + if (miniflow_funcs[i].available) { + hitmask = miniflow_funcs[i].extract_func(packets, keys, keys_size, + in_port, pmd_handle); + stats->impl_hitcount[i] += count_1bits(hitmask); + + /* If traffic is not classified than we dont overwrite the keys + * array in minfiflow implementations so its safe to create a + * mask for all those packets whose miniflow have been created. */ + mask |= hitmask; + } + } + stats->pkt_count += dp_packet_batch_size(packets); + + /* Choose the best implementation after a minimum packets have been + * processed. */ + if (stats->pkt_count >= MFEX_MAX_COUNT) { + uint32_t best_func_index = MFEX_IMPL_START_IDX; + uint32_t max_hits = 0; + for (int i = MFEX_IMPL_START_IDX; i < impl_count; i++) { + if (stats->impl_hitcount[i] > max_hits) { + max_hits = stats->impl_hitcount[i]; + best_func_index = i; + } + } + + if (max_hits >= MFEX_MIN_HIT_COUNT_FOR_USE) { + /* Set the implementation to index with max_hits. */ + pmd->miniflow_extract_opt = + miniflow_funcs[best_func_index].extract_func; + VLOG_INFO("MFEX study chose impl %s: (hits %d/%d pkts)\n", + miniflow_funcs[best_func_index].name, max_hits, + stats->pkt_count); + } else { + /* Set the implementation to null for default miniflow. */ + pmd->miniflow_extract_opt = NULL; + VLOG_INFO("Not enough packets matched (%d/%d), disabling" + " optimized MFEX.\n", max_hits, stats->pkt_count); + } + /* Reset stats so that study function can be called again + * for next traffic type and optimal function ptr can be + * choosen. */ + memset(stats, 0, sizeof(struct study_stats)); + } + return mask; +} diff --git a/lib/dpif-netdev-private-extract.c b/lib/dpif-netdev-private-extract.c index 0741c19f9..d86268a1d 100644 --- a/lib/dpif-netdev-private-extract.c +++ b/lib/dpif-netdev-private-extract.c @@ -42,6 +42,11 @@ static struct dpif_miniflow_extract_impl mfex_impls[] = { .extract_func = NULL, .name = "disable", }, + { + .probe = NULL, + .extract_func = mfex_study_traffic, + .name = "study", + }, }; BUILD_ASSERT_DECL(MFEX_IMPLS_MAX_SIZE > ARRAY_SIZE(mfex_impls)); diff --git a/lib/dpif-netdev-private-extract.h b/lib/dpif-netdev-private-extract.h index 455a7b590..3ada413bb 100644 --- a/lib/dpif-netdev-private-extract.h +++ b/lib/dpif-netdev-private-extract.h @@ -27,7 +27,7 @@ /* Skip the autovalidator study and null when iterating all available * miniflow implementations. */ -#define MFEX_IMPL_START_IDX (1) +#define MFEX_IMPL_START_IDX (3) /* Forward declarations. */ struct dp_packet; @@ -106,4 +106,16 @@ dpif_miniflow_extract_autovalidator(struct dp_packet_batch *batch, uint32_t keys_size, odp_port_t in_port, void *pmd_handle); +/* Retrieve the number of packets by studying packets using different miniflow + * implementations to choose the best implementation using the maximum hitmask + * count. + * On error, returns a zero for no packets. + * On success, returns mask of the packets hit. + */ +uint32_t +mfex_study_traffic(struct dp_packet_batch *packets, + struct netdev_flow_key *keys, + uint32_t keys_size, odp_port_t in_port, + void *pmd_handle); + #endif /* DPIF_NETDEV_AVX512_EXTRACT */ -- 2.25.1 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev