+++ /dev/null
-/*-
- * 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_memory.h>
-#include <rte_memzone.h>
-#include <rte_errno.h>
-#include <rte_string_fns.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)
-
-/**
- * Maximum number of workers allowed.
- * Be aware of increasing the limit, becaus it is limited by how we track
- * in-flight tags. See @in_flight_bitmask and @rte_distributor_process
- */
-#define RTE_DISTRIB_MAX_WORKERS 64
-
-/**
- * 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[RTE_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_DISTRIB_MAX_WORKERS];
- /**< Tracks the tag being processed per core */
- uint64_t in_flight_bitmask;
- /**< on/off bits for in-flight tags.
- * Note that if RTE_DISTRIB_MAX_WORKERS is larger than 64 then
- * the bitmask has to expand.
- */
-
- struct rte_distributor_backlog backlog[RTE_DISTRIB_MAX_WORKERS];
-
- union rte_distributor_buffer bufs[RTE_DISTRIB_MAX_WORKERS];
-
- struct rte_distributor_returned_pkts returns;
-};
-
-TAILQ_HEAD(rte_distributor_list, rte_distributor);
-
-static struct rte_tailq_elem rte_distributor_tailq = {
- .name = "RTE_DISTRIBUTOR",
-};
-EAL_REGISTER_TAILQ(rte_distributor_tailq)
-
-/**** APIs called by workers ****/
-
-void
-rte_distributor_request_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;
-}
-
-struct rte_mbuf *
-rte_distributor_poll_pkt(struct rte_distributor *d,
- unsigned worker_id)
-{
- union rte_distributor_buffer *buf = &d->bufs[worker_id];
- if (buf->bufptr64 & RTE_DISTRIB_GET_BUF)
- return NULL;
-
- /* 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);
-}
-
-struct rte_mbuf *
-rte_distributor_get_pkt(struct rte_distributor *d,
- unsigned worker_id, struct rte_mbuf *oldpkt)
-{
- struct rte_mbuf *ret;
- rte_distributor_request_pkt(d, worker_id, oldpkt);
- while ((ret = rte_distributor_poll_pkt(d, worker_id)) == NULL)
- rte_pause();
- return 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->in_flight_bitmask &= ~(1UL << wkr);
- 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.
- * Note that the tags were set before first level call
- * to rte_distributor_process.
- */
- 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;
- d->in_flight_bitmask &= ~(1UL << wkr);
- }
- 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);
- /*
- * User is advocated to set tag vaue for each
- * mbuf before calling rte_distributor_process.
- * User defined tags are used to identify flows,
- * or sessions.
- */
- new_tag = next_mb->hash.usr;
-
- /*
- * Note that if RTE_DISTRIB_MAX_WORKERS is larger than 64
- * then the size of match has to be expanded.
- */
- uint64_t match = 0;
- unsigned i;
- /*
- * to scan for a match use "xor" and "not" to get a 0/1
- * value, then use shifting to merge to single "match"
- * variable, where a one-bit indicates a match for the
- * worker given by the bit-position
- */
- for (i = 0; i < d->num_workers; i++)
- match |= (!(d->in_flight_tags[i] ^ new_tag)
- << i);
-
- /* Only turned-on bits are considered as match */
- match &= d->in_flight_bitmask;
-
- if (match) {
- next_mb = NULL;
- unsigned worker = __builtin_ctzl(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;
- d->in_flight_bitmask |= (1UL << wkr);
- 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;
-}
-
-/* return the number of packets in-flight in a distributor, i.e. packets
- * being workered on or queued up in a backlog. */
-static inline unsigned
-total_outstanding(const struct rte_distributor *d)
-{
- unsigned wkr, total_outstanding;
-
- total_outstanding = __builtin_popcountl(d->in_flight_bitmask);
-
- for (wkr = 0; wkr < d->num_workers; wkr++)
- total_outstanding += d->backlog[wkr].count;
-
- return total_outstanding;
-}
-
-/* flush the distributor, so that there are no outstanding packets in flight or
- * queued up. */
-int
-rte_distributor_flush(struct rte_distributor *d)
-{
- const unsigned flushed = total_outstanding(d);
-
- while (total_outstanding(d) > 0)
- rte_distributor_process(d, NULL, 0);
-
- 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) & RTE_CACHE_LINE_MASK) != 0);
- RTE_BUILD_BUG_ON((RTE_DISTRIB_MAX_WORKERS & 7) != 0);
- RTE_BUILD_BUG_ON(RTE_DISTRIB_MAX_WORKERS >
- sizeof(d->in_flight_bitmask) * CHAR_BIT);
-
- if (name == NULL || num_workers >= RTE_DISTRIB_MAX_WORKERS) {
- rte_errno = EINVAL;
- return NULL;
- }
-
- 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;
- snprintf(d->name, sizeof(d->name), "%s", name);
- d->num_workers = num_workers;
-
- distributor_list = RTE_TAILQ_CAST(rte_distributor_tailq.head,
- rte_distributor_list);
-
- 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;
-}
git.droids-corp.org / dpdk.git / blobdiff