This adds the code for a new Intel DPDK library for packet distribution.
The distributor is a component which is designed to pass packets
one-at-a-time to workers, with dynamic load balancing. Using the RSS
field in the mbuf as a tag, the distributor tracks what packet tag is
being processed by what worker and then ensures that no two packets with
the same tag are in-flight simultaneously. Once a tag is not in-flight,
then the next packet with that tag will be sent to the next available
core.
Changes in V2 patch :
* added support for a partial distributor flush when process() API
called without any new mbufs
* Removed unused "future use" parameters from functions
* Improved comments to be clearer about thread safety
* Add locks around the tailq add in create() API fn
* Stylistic improvements for issues flagged by checkpatch
Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
---
lib/librte_distributor/Makefile | 50 ++++
lib/librte_distributor/rte_distributor.c | 487 +++++++++++++++++++++++++++++++
lib/librte_distributor/rte_distributor.h | 186 ++++++++++++
3 files changed, 723 insertions(+)
create mode 100644 lib/librte_distributor/Makefile
create mode 100644 lib/librte_distributor/rte_distributor.c
create mode 100644 lib/librte_distributor/rte_distributor.h
diff --git a/lib/librte_distributor/Makefile b/lib/librte_distributor/Makefile
new file mode 100644
index 0000000..36699f8
--- /dev/null
+++ b/lib/librte_distributor/Makefile
@@ -0,0 +1,50 @@
+# BSD LICENSE
+#
+# Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in
+# the documentation and/or other materials provided with the
+# distribution.
+# * Neither the name of Intel Corporation nor the names of its
+# contributors may be used to endorse or promote products derived
+# from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+include $(RTE_SDK)/mk/rte.vars.mk
+
+# library name
+LIB = librte_distributor.a
+
+CFLAGS += -O3
+CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR)
+
+# all source are stored in SRCS-y
+SRCS-$(CONFIG_RTE_LIBRTE_DISTRIBUTOR) := rte_distributor.c
+
+# install this header file
+SYMLINK-$(CONFIG_RTE_LIBRTE_DISTRIBUTOR)-include := rte_distributor.h
+
+# this lib needs eal
+DEPDIRS-$(CONFIG_RTE_LIBRTE_DISTRIBUTOR) += lib/librte_eal
+DEPDIRS-$(CONFIG_RTE_LIBRTE_DISTRIBUTOR) += lib/librte_mbuf
+
+include $(RTE_SDK)/mk/rte.lib.mk
diff --git a/lib/librte_distributor/rte_distributor.c
b/lib/librte_distributor/rte_distributor.c
new file mode 100644
index 0000000..35b7da3
--- /dev/null
+++ b/lib/librte_distributor/rte_distributor.c
@@ -0,0 +1,487 @@
+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <sys/queue.h>
+#include <string.h>
+#include <rte_mbuf.h>
+#include <rte_memzone.h>
+#include <rte_errno.h>
+#include <rte_string_fns.h>
+#include <rte_tailq.h>
+#include <rte_eal_memconfig.h>
+#include "rte_distributor.h"
+
+#define NO_FLAGS 0
+#define RTE_DISTRIB_PREFIX "DT_"
+
+/* we will use the bottom four bits of pointer for flags, shifting out
+ * the top four bits to make room (since a 64-bit pointer actually only uses
+ * 48 bits). An arithmetic-right-shift will then appropriately restore the
+ * original pointer value with proper sign extension into the top bits. */
+#define RTE_DISTRIB_FLAG_BITS 4
+#define RTE_DISTRIB_FLAGS_MASK (0x0F)
+#define RTE_DISTRIB_NO_BUF 0 /**< empty flags: no buffer requested */
+#define RTE_DISTRIB_GET_BUF (1) /**< worker requests a buffer, returns old
*/
+#define RTE_DISTRIB_RETURN_BUF (2) /**< worker returns a buffer, no request */
+
+#define RTE_DISTRIB_BACKLOG_SIZE 8
+#define RTE_DISTRIB_BACKLOG_MASK (RTE_DISTRIB_BACKLOG_SIZE - 1)
+
+#define RTE_DISTRIB_MAX_RETURNS 128
+#define RTE_DISTRIB_RETURNS_MASK (RTE_DISTRIB_MAX_RETURNS - 1)
+
+/**
+ * Buffer structure used to pass the pointer data between cores. This is cache
+ * line aligned, but to improve performance and prevent adjacent cache-line
+ * prefetches of buffers for other workers, e.g. when worker 1's buffer is on
+ * the next cache line to worker 0, we pad this out to three cache lines.
+ * Only 64-bits of the memory is actually used though.
+ */
+union rte_distributor_buffer {
+ volatile int64_t bufptr64;
+ char pad[CACHE_LINE_SIZE*3];
+} __rte_cache_aligned;
+
+struct rte_distributor_backlog {
+ unsigned start;
+ unsigned count;
+ int64_t pkts[RTE_DISTRIB_BACKLOG_SIZE];
+};
+
+struct rte_distributor_returned_pkts {
+ unsigned start;
+ unsigned count;
+ struct rte_mbuf *mbufs[RTE_DISTRIB_MAX_RETURNS];
+};
+
+struct rte_distributor {
+ TAILQ_ENTRY(rte_distributor) next; /**< Next in list. */
+
+ char name[RTE_DISTRIBUTOR_NAMESIZE]; /**< Name of the ring. */
+ unsigned num_workers; /**< Number of workers polling */
+
+ uint32_t in_flight_tags[RTE_MAX_LCORE];
+ struct rte_distributor_backlog backlog[RTE_MAX_LCORE];
+
+ union rte_distributor_buffer bufs[RTE_MAX_LCORE];
+
+ struct rte_distributor_returned_pkts returns;
+};
+
+TAILQ_HEAD(rte_distributor_list, rte_distributor);
+
+/**** APIs called by workers ****/
+
+struct rte_mbuf *
+rte_distributor_get_pkt(struct rte_distributor *d,
+ unsigned worker_id, struct rte_mbuf *oldpkt)
+{
+ union rte_distributor_buffer *buf = &d->bufs[worker_id];
+ int64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS)
+ | RTE_DISTRIB_GET_BUF;
+ while (unlikely(buf->bufptr64 & RTE_DISTRIB_FLAGS_MASK))
+ rte_pause();
+ buf->bufptr64 = req;
+ while (buf->bufptr64 & RTE_DISTRIB_GET_BUF)
+ rte_pause();
+ /* since bufptr64 is signed, this should be an arithmetic shift */
+ int64_t ret = buf->bufptr64 >> RTE_DISTRIB_FLAG_BITS;
+ return (struct rte_mbuf *)((uintptr_t)ret);
+}
+
+int
+rte_distributor_return_pkt(struct rte_distributor *d,
+ unsigned worker_id, struct rte_mbuf *oldpkt)
+{
+ union rte_distributor_buffer *buf = &d->bufs[worker_id];
+ uint64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS)
+ | RTE_DISTRIB_RETURN_BUF;
+ buf->bufptr64 = req;
+ return 0;
+}
+
+/**** APIs called on distributor core ***/
+
+/* as name suggests, adds a packet to the backlog for a particular worker */
+static int
+add_to_backlog(struct rte_distributor_backlog *bl, int64_t item)
+{
+ if (bl->count == RTE_DISTRIB_BACKLOG_SIZE)
+ return -1;
+
+ bl->pkts[(bl->start + bl->count++) & (RTE_DISTRIB_BACKLOG_MASK)]
+ = item;
+ return 0;
+}
+
+/* takes the next packet for a worker off the backlog */
+static int64_t
+backlog_pop(struct rte_distributor_backlog *bl)
+{
+ bl->count--;
+ return bl->pkts[bl->start++ & RTE_DISTRIB_BACKLOG_MASK];
+}
+
+/* stores a packet returned from a worker inside the returns array */
+static inline void
+store_return(uintptr_t oldbuf, struct rte_distributor *d,
+ unsigned *ret_start, unsigned *ret_count)
+{
+ /* store returns in a circular buffer - code is branch-free */
+ d->returns.mbufs[(*ret_start + *ret_count) & RTE_DISTRIB_RETURNS_MASK]
+ = (void *)oldbuf;
+ *ret_start += (*ret_count == RTE_DISTRIB_RETURNS_MASK) & !!(oldbuf);
+ *ret_count += (*ret_count != RTE_DISTRIB_RETURNS_MASK) & !!(oldbuf);
+}
+
+static inline void
+handle_worker_shutdown(struct rte_distributor *d, unsigned wkr)
+{
+ d->in_flight_tags[wkr] = 0;
+ d->bufs[wkr].bufptr64 = 0;
+ if (unlikely(d->backlog[wkr].count != 0)) {
+ /* On return of a packet, we need to move the
+ * queued packets for this core elsewhere.
+ * Easiest solution is to set things up for
+ * a recursive call. That will cause those
+ * packets to be queued up for the next free
+ * core, i.e. it will return as soon as a
+ * core becomes free to accept the first
+ * packet, as subsequent ones will be added to
+ * the backlog for that core.
+ */
+ struct rte_mbuf *pkts[RTE_DISTRIB_BACKLOG_SIZE];
+ unsigned i;
+ struct rte_distributor_backlog *bl = &d->backlog[wkr];
+
+ for (i = 0; i < bl->count; i++) {
+ unsigned idx = (bl->start + i) &
+ RTE_DISTRIB_BACKLOG_MASK;
+ pkts[i] = (void *)((uintptr_t)(bl->pkts[idx] >>
+ RTE_DISTRIB_FLAG_BITS));
+ }
+ /* recursive call */
+ rte_distributor_process(d, pkts, i);
+ bl->count = bl->start = 0;
+ }
+}
+
+/* this function is called when process() fn is called without any new
+ * packets. It goes through all the workers and clears any returned packets
+ * to do a partial flush.
+ */
+static int
+process_returns(struct rte_distributor *d)
+{
+ unsigned wkr;
+ unsigned flushed = 0;
+ unsigned ret_start = d->returns.start,
+ ret_count = d->returns.count;
+
+ for (wkr = 0; wkr < d->num_workers; wkr++) {
+
+ const int64_t data = d->bufs[wkr].bufptr64;
+ uintptr_t oldbuf = 0;
+
+ if (data & RTE_DISTRIB_GET_BUF) {
+ flushed++;
+ if (d->backlog[wkr].count)
+ d->bufs[wkr].bufptr64 =
+ backlog_pop(&d->backlog[wkr]);
+ else {
+ d->bufs[wkr].bufptr64 = RTE_DISTRIB_GET_BUF;
+ d->in_flight_tags[wkr] = 0;
+ }
+ oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
+ } else if (data & RTE_DISTRIB_RETURN_BUF) {
+ handle_worker_shutdown(d, wkr);
+ oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
+ }
+
+ store_return(oldbuf, d, &ret_start, &ret_count);
+ }
+
+ d->returns.start = ret_start;
+ d->returns.count = ret_count;
+
+ return flushed;
+}
+
+/* process a set of packets to distribute them to workers */
+int
+rte_distributor_process(struct rte_distributor *d,
+ struct rte_mbuf **mbufs, unsigned num_mbufs)
+{
+ unsigned next_idx = 0;
+ unsigned wkr = 0;
+ struct rte_mbuf *next_mb = NULL;
+ int64_t next_value = 0;
+ uint32_t new_tag = 0;
+ unsigned ret_start = d->returns.start,
+ ret_count = d->returns.count;
+
+ if (unlikely(num_mbufs == 0))
+ return process_returns(d);
+
+ while (next_idx < num_mbufs || next_mb != NULL) {
+
+ int64_t data = d->bufs[wkr].bufptr64;
+ uintptr_t oldbuf = 0;
+
+ if (!next_mb) {
+ next_mb = mbufs[next_idx++];
+ next_value = (((int64_t)(uintptr_t)next_mb)
+ << RTE_DISTRIB_FLAG_BITS);
+ new_tag = (next_mb->pkt.hash.rss | 1);
+
+ uint32_t match = 0;
+ unsigned i;
+ for (i = 0; i < d->num_workers; i++)
+ match |= (!(d->in_flight_tags[i] ^ new_tag)
+ << i);
+
+ if (match) {
+ next_mb = NULL;
+ unsigned worker = __builtin_ctz(match);
+ if (add_to_backlog(&d->backlog[worker],
+ next_value) < 0)
+ next_idx--;
+ }
+ }
+
+ if ((data & RTE_DISTRIB_GET_BUF) &&
+ (d->backlog[wkr].count || next_mb)) {
+
+ if (d->backlog[wkr].count)
+ d->bufs[wkr].bufptr64 =
+ backlog_pop(&d->backlog[wkr]);
+
+ else {
+ d->bufs[wkr].bufptr64 = next_value;
+ d->in_flight_tags[wkr] = new_tag;
+ next_mb = NULL;
+ }
+ oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
+ } else if (data & RTE_DISTRIB_RETURN_BUF) {
+ handle_worker_shutdown(d, wkr);
+ oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
+ }
+
+ /* store returns in a circular buffer */
+ store_return(oldbuf, d, &ret_start, &ret_count);
+
+ if (++wkr == d->num_workers)
+ wkr = 0;
+ }
+ /* to finish, check all workers for backlog and schedule work for them
+ * if they are ready */
+ for (wkr = 0; wkr < d->num_workers; wkr++)
+ if (d->backlog[wkr].count &&
+ (d->bufs[wkr].bufptr64 & RTE_DISTRIB_GET_BUF)) {
+
+ int64_t oldbuf = d->bufs[wkr].bufptr64 >>
+ RTE_DISTRIB_FLAG_BITS;
+ store_return(oldbuf, d, &ret_start, &ret_count);
+
+ d->bufs[wkr].bufptr64 = backlog_pop(&d->backlog[wkr]);
+ }
+
+ d->returns.start = ret_start;
+ d->returns.count = ret_count;
+ return num_mbufs;
+}
+
+/* return to the caller, packets returned from workers */
+int
+rte_distributor_returned_pkts(struct rte_distributor *d,
+ struct rte_mbuf **mbufs, unsigned max_mbufs)
+{
+ struct rte_distributor_returned_pkts *returns = &d->returns;
+ unsigned retval = (max_mbufs < returns->count) ?
+ max_mbufs : returns->count;
+ unsigned i;
+
+ for (i = 0; i < retval; i++) {
+ unsigned idx = (returns->start + i) & RTE_DISTRIB_RETURNS_MASK;
+ mbufs[i] = returns->mbufs[idx];
+ }
+ returns->start += i;
+ returns->count -= i;
+
+ return retval;
+}
+
+/* local function used by the flush function only, to reassign a backlog for
+ * a shutdown core. The process function uses a recursive call for this, but
+ * that is not done in flush, as we need to track the outstanding packets
count.
+ */
+static inline int
+move_backlog(struct rte_distributor *d, unsigned worker)
+{
+ struct rte_distributor_backlog *bl = &d->backlog[worker];
+ unsigned i;
+
+ for (i = 0; i < d->num_workers; i++) {
+ if (i == worker)
+ continue;
+ /* check worker is active and then if backlog will fit */
+ if ((d->in_flight_tags[i] != 0 ||
+ (d->bufs[i].bufptr64 & RTE_DISTRIB_GET_BUF)) &&
+ (bl->count + d->backlog[i].count)
+ <= RTE_DISTRIB_BACKLOG_SIZE) {
+ while (bl->count)
+ add_to_backlog(&d->backlog[i], backlog_pop(bl));
+ return 0;
+ }
+ }
+ return -1;
+}
+
+/* flush the distributor, so that there are no outstanding packets in flight or
+ * queued up. */
+int
+rte_distributor_flush(struct rte_distributor *d)
+{
+ unsigned wkr, total_outstanding = 0;
+ unsigned flushed = 0;
+ unsigned ret_start = d->returns.start,
+ ret_count = d->returns.count;
+
+ for (wkr = 0; wkr < d->num_workers; wkr++)
+ total_outstanding += d->backlog[wkr].count +
+ !!(d->in_flight_tags[wkr]);
+
+ wkr = 0;
+ while (flushed < total_outstanding) {
+
+ if (d->in_flight_tags[wkr] != 0 || d->backlog[wkr].count) {
+ const int64_t data = d->bufs[wkr].bufptr64;
+ uintptr_t oldbuf = 0;
+
+ if (data & RTE_DISTRIB_GET_BUF) {
+ flushed += (d->in_flight_tags[wkr] != 0);
+ if (d->backlog[wkr].count) {
+ d->bufs[wkr].bufptr64 =
+ backlog_pop(&d->backlog[wkr]);
+ /* we need to mark something as being
+ * in-flight, but it doesn't matter what
+ * as we never check it except
+ * to check for non-zero.
+ */
+ d->in_flight_tags[wkr] = 1;
+ } else {
+ d->bufs[wkr].bufptr64 =
+ RTE_DISTRIB_GET_BUF;
+ d->in_flight_tags[wkr] = 0;
+ }
+ oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
+ } else if (data & RTE_DISTRIB_RETURN_BUF) {
+ if (d->backlog[wkr].count == 0 ||
+ move_backlog(d, wkr) == 0) {
+ /* only if we move backlog,
+ * process this packet */
+ d->bufs[wkr].bufptr64 = 0;
+ oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
+ flushed++;
+ d->in_flight_tags[wkr] = 0;
+ }
+ }
+
+ store_return(oldbuf, d, &ret_start, &ret_count);
+ }
+
+ if (++wkr == d->num_workers)
+ wkr = 0;
+ }
+ d->returns.start = ret_start;
+ d->returns.count = ret_count;
+
+ return flushed;
+}
+
+/* clears the internal returns array in the distributor */
+void
+rte_distributor_clear_returns(struct rte_distributor *d)
+{
+ d->returns.start = d->returns.count = 0;
+#ifndef __OPTIMIZE__
+ memset(d->returns.mbufs, 0, sizeof(d->returns.mbufs));
+#endif
+}
+
+/* creates a distributor instance */
+struct rte_distributor *
+rte_distributor_create(const char *name,
+ unsigned socket_id,
+ unsigned num_workers)
+{
+ struct rte_distributor *d;
+ struct rte_distributor_list *distributor_list;
+ char mz_name[RTE_MEMZONE_NAMESIZE];
+ const struct rte_memzone *mz;
+
+ /* compilation-time checks */
+ RTE_BUILD_BUG_ON((sizeof(*d) & CACHE_LINE_MASK) != 0);
+ RTE_BUILD_BUG_ON((RTE_MAX_LCORE & 7) != 0);
+
+ if (name == NULL || num_workers >= RTE_MAX_LCORE) {
+ rte_errno = EINVAL;
+ return NULL;
+ }
+
+ /* check that we have an initialised tail queue */
+ distributor_list = RTE_TAILQ_LOOKUP_BY_IDX(RTE_TAILQ_DISTRIBUTOR,
+ rte_distributor_list);
+ if (distributor_list == NULL) {
+ rte_errno = E_RTE_NO_TAILQ;
+ return NULL;
+ }
+
+ rte_snprintf(mz_name, sizeof(mz_name), RTE_DISTRIB_PREFIX"%s", name);
+ mz = rte_memzone_reserve(mz_name, sizeof(*d), socket_id, NO_FLAGS);
+ if (mz == NULL) {
+ rte_errno = ENOMEM;
+ return NULL;
+ }
+
+ d = mz->addr;
+ rte_snprintf(d->name, sizeof(d->name), "%s", name);
+ d->num_workers = num_workers;
+
+ rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
+ TAILQ_INSERT_TAIL(distributor_list, d, next);
+ rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
+
+ return d;
+}
diff --git a/lib/librte_distributor/rte_distributor.h
b/lib/librte_distributor/rte_distributor.h
new file mode 100644
index 0000000..d8e953f
--- /dev/null
+++ b/lib/librte_distributor/rte_distributor.h
@@ -0,0 +1,186 @@
+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _RTE_DISTRIBUTE_H_
+#define _RTE_DISTRIBUTE_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <rte_mbuf.h>
+
+#define RTE_DISTRIBUTOR_NAMESIZE 32 /**< Length of name for instance */
+
+struct rte_distributor;
+
+/**
+ * Function to create a new distributor instance
+ *
+ * Reserves the memory needed for the distributor operation and
+ * initializes the distributor to work with the configured number of workers.
+ *
+ * @param name
+ * The name to be given to the distributor instance.
+ * @param socket_id
+ * The NUMA node on which the memory is to be allocated
+ * @param num_workers
+ * The maximum number of workers that will request packets from this
+ * distributor
+ * @return
+ * The newly created distributor instance
+ */
+struct rte_distributor *
+rte_distributor_create(const char *name, unsigned socket_id,
+ unsigned num_workers);
+
+/* *** APIS to be called on the distributor lcore *** */
+/*
+ * The following APIs are the public APIs which are designed for use on a
+ * single lcore which acts as the distributor lcore for a given distributor
+ * instance. These functions cannot be called on multiple cores simultaneously
+ * without using locking to protect access to the internals of the distributor.
+ *
+ * NOTE: a given lcore cannot act as both a distributor lcore and a worker
lcore
+ * for the same distributor instance, otherwise deadlock will result.
+ */
+
+/**
+ * Process a set of packets by distributing them among workers that request
+ * packets. The distributor will ensure that no two packets that have the
+ * same flow id, or tag, in the mbuf will be procesed at the same time.
+ *
+ * @param d
+ * The distributor instance to be used
+ * @param mbufs
+ * The mbufs to be distributed
+ * @param num_mbufs
+ * The number of mbufs in the mbufs array
+ * @return
+ * The number of mbufs processed.
+ */
+int
+rte_distributor_process(struct rte_distributor *d,
+ struct rte_mbuf **mbufs, unsigned num_mbufs);
+
+/**
+ * Get a set of mbufs that have been returned to the distributor by workers
+ *
+ * @param d
+ * The distributor instance to be used
+ * @param mbufs
+ * The mbufs pointer array to be filled in
+ * @param max_mbufs
+ * The size of the mbufs array
+ * @return
+ * The number of mbufs returned in the mbufs array.
+ */
+int
+rte_distributor_returned_pkts(struct rte_distributor *d,
+ struct rte_mbuf **mbufs, unsigned max_mbufs);
+
+/**
+ * Flush the distributor component, so that there are no in-flight or
+ * backlogged packets awaiting processing
+ *
+ * @param d
+ * The distributor instance to be used
+ * @return
+ * The number of queued/in-flight packets that were completed by this call.
+ */
+int
+rte_distributor_flush(struct rte_distributor *d);
+
+/**
+ * Clears the array of returned packets used as the source for the
+ * rte_distributor_returned_pkts() API call.
+ *
+ * @param d
+ * The distributor instance to be used
+ */
+void
+rte_distributor_clear_returns(struct rte_distributor *d);
+
+/* *** APIS to be called on the worker lcores *** */
+/*
+ * The following APIs are the public APIs which are designed for use on
+ * multiple lcores which act as workers for a distributor. Each lcore should
use
+ * a unique worker id when requesting packets.
+ *
+ * NOTE: a given lcore cannot act as both a distributor lcore and a worker
lcore
+ * for the same distributor instance, otherwise deadlock will result.
+ */
+
+/**
+ * API called by a worker to get a new packet to process. Any previous packet
+ * given to the worker is assumed to have completed processing, and may be
+ * optionally returned to the distributor via the oldpkt parameter.
+ *
+ * @param d
+ * The distributor instance to be used
+ * @param worker_id
+ * The worker instance number to use - must be less that num_workers passed
+ * at distributor creation time.
+ * @param oldpkt
+ * The previous packet, if any, being processed by the worker
+ *
+ * @return
+ * A new packet to be processed by the worker thread.
+ */
+struct rte_mbuf *
+rte_distributor_get_pkt(struct rte_distributor *d,
+ unsigned worker_id, struct rte_mbuf *oldpkt);
+
+/**
+ * API called by a worker to return a completed packet without requesting a
+ * new packet, for example, because a worker thread is shutting down
+ *
+ * @param d
+ * The distributor instance to be used
+ * @param worker_id
+ * The worker instance number to use - must be less that num_workers passed
+ * at distributor creation time.
+ * @param mbuf
+ * The previous packet being processed by the worker
+ */
+int
+rte_distributor_return_pkt(struct rte_distributor *d, unsigned worker_id,
+ struct rte_mbuf *mbuf);
+
+/******************************************/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
--
1.9.3
