488 lines
14 KiB
C
488 lines
14 KiB
C
/*-
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* BSD LICENSE
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*
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* Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <sys/queue.h>
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#include <string.h>
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#include <rte_mbuf.h>
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#include <rte_memory.h>
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#include <rte_memzone.h>
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#include <rte_errno.h>
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#include <rte_string_fns.h>
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#include <rte_eal_memconfig.h>
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#include "rte_distributor.h"
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#define NO_FLAGS 0
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#define RTE_DISTRIB_PREFIX "DT_"
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/* we will use the bottom four bits of pointer for flags, shifting out
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* the top four bits to make room (since a 64-bit pointer actually only uses
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* 48 bits). An arithmetic-right-shift will then appropriately restore the
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* original pointer value with proper sign extension into the top bits. */
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#define RTE_DISTRIB_FLAG_BITS 4
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#define RTE_DISTRIB_FLAGS_MASK (0x0F)
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#define RTE_DISTRIB_NO_BUF 0 /**< empty flags: no buffer requested */
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#define RTE_DISTRIB_GET_BUF (1) /**< worker requests a buffer, returns old */
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#define RTE_DISTRIB_RETURN_BUF (2) /**< worker returns a buffer, no request */
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#define RTE_DISTRIB_BACKLOG_SIZE 8
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#define RTE_DISTRIB_BACKLOG_MASK (RTE_DISTRIB_BACKLOG_SIZE - 1)
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#define RTE_DISTRIB_MAX_RETURNS 128
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#define RTE_DISTRIB_RETURNS_MASK (RTE_DISTRIB_MAX_RETURNS - 1)
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/**
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* Maximum number of workers allowed.
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* Be aware of increasing the limit, becaus it is limited by how we track
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* in-flight tags. See @in_flight_bitmask and @rte_distributor_process
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*/
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#define RTE_DISTRIB_MAX_WORKERS 64
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/**
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* Buffer structure used to pass the pointer data between cores. This is cache
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* line aligned, but to improve performance and prevent adjacent cache-line
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* prefetches of buffers for other workers, e.g. when worker 1's buffer is on
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* the next cache line to worker 0, we pad this out to three cache lines.
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* Only 64-bits of the memory is actually used though.
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*/
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union rte_distributor_buffer {
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volatile int64_t bufptr64;
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char pad[RTE_CACHE_LINE_SIZE*3];
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} __rte_cache_aligned;
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struct rte_distributor_backlog {
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unsigned start;
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unsigned count;
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int64_t pkts[RTE_DISTRIB_BACKLOG_SIZE];
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};
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struct rte_distributor_returned_pkts {
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unsigned start;
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unsigned count;
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struct rte_mbuf *mbufs[RTE_DISTRIB_MAX_RETURNS];
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};
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struct rte_distributor {
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TAILQ_ENTRY(rte_distributor) next; /**< Next in list. */
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char name[RTE_DISTRIBUTOR_NAMESIZE]; /**< Name of the ring. */
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unsigned num_workers; /**< Number of workers polling */
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uint32_t in_flight_tags[RTE_DISTRIB_MAX_WORKERS];
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/**< Tracks the tag being processed per core */
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uint64_t in_flight_bitmask;
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/**< on/off bits for in-flight tags.
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* Note that if RTE_DISTRIB_MAX_WORKERS is larger than 64 then
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* the bitmask has to expand.
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*/
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struct rte_distributor_backlog backlog[RTE_DISTRIB_MAX_WORKERS];
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union rte_distributor_buffer bufs[RTE_DISTRIB_MAX_WORKERS];
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struct rte_distributor_returned_pkts returns;
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};
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TAILQ_HEAD(rte_distributor_list, rte_distributor);
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static struct rte_tailq_elem rte_distributor_tailq = {
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.name = "RTE_DISTRIBUTOR",
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};
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EAL_REGISTER_TAILQ(rte_distributor_tailq)
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/**** APIs called by workers ****/
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void
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rte_distributor_request_pkt(struct rte_distributor *d,
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unsigned worker_id, struct rte_mbuf *oldpkt)
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{
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union rte_distributor_buffer *buf = &d->bufs[worker_id];
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int64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS)
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| RTE_DISTRIB_GET_BUF;
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while (unlikely(buf->bufptr64 & RTE_DISTRIB_FLAGS_MASK))
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rte_pause();
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buf->bufptr64 = req;
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}
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struct rte_mbuf *
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rte_distributor_poll_pkt(struct rte_distributor *d,
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unsigned worker_id)
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{
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union rte_distributor_buffer *buf = &d->bufs[worker_id];
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if (buf->bufptr64 & RTE_DISTRIB_GET_BUF)
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return NULL;
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/* since bufptr64 is signed, this should be an arithmetic shift */
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int64_t ret = buf->bufptr64 >> RTE_DISTRIB_FLAG_BITS;
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return (struct rte_mbuf *)((uintptr_t)ret);
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}
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struct rte_mbuf *
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rte_distributor_get_pkt(struct rte_distributor *d,
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unsigned worker_id, struct rte_mbuf *oldpkt)
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{
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struct rte_mbuf *ret;
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rte_distributor_request_pkt(d, worker_id, oldpkt);
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while ((ret = rte_distributor_poll_pkt(d, worker_id)) == NULL)
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rte_pause();
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return ret;
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}
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int
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rte_distributor_return_pkt(struct rte_distributor *d,
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unsigned worker_id, struct rte_mbuf *oldpkt)
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{
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union rte_distributor_buffer *buf = &d->bufs[worker_id];
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uint64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS)
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| RTE_DISTRIB_RETURN_BUF;
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buf->bufptr64 = req;
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return 0;
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}
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/**** APIs called on distributor core ***/
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/* as name suggests, adds a packet to the backlog for a particular worker */
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static int
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add_to_backlog(struct rte_distributor_backlog *bl, int64_t item)
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{
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if (bl->count == RTE_DISTRIB_BACKLOG_SIZE)
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return -1;
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bl->pkts[(bl->start + bl->count++) & (RTE_DISTRIB_BACKLOG_MASK)]
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= item;
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return 0;
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}
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/* takes the next packet for a worker off the backlog */
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static int64_t
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backlog_pop(struct rte_distributor_backlog *bl)
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{
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bl->count--;
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return bl->pkts[bl->start++ & RTE_DISTRIB_BACKLOG_MASK];
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}
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/* stores a packet returned from a worker inside the returns array */
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static inline void
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store_return(uintptr_t oldbuf, struct rte_distributor *d,
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unsigned *ret_start, unsigned *ret_count)
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{
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/* store returns in a circular buffer - code is branch-free */
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d->returns.mbufs[(*ret_start + *ret_count) & RTE_DISTRIB_RETURNS_MASK]
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= (void *)oldbuf;
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*ret_start += (*ret_count == RTE_DISTRIB_RETURNS_MASK) & !!(oldbuf);
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*ret_count += (*ret_count != RTE_DISTRIB_RETURNS_MASK) & !!(oldbuf);
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}
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static inline void
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handle_worker_shutdown(struct rte_distributor *d, unsigned wkr)
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{
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d->in_flight_tags[wkr] = 0;
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d->in_flight_bitmask &= ~(1UL << wkr);
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d->bufs[wkr].bufptr64 = 0;
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if (unlikely(d->backlog[wkr].count != 0)) {
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/* On return of a packet, we need to move the
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* queued packets for this core elsewhere.
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* Easiest solution is to set things up for
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* a recursive call. That will cause those
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* packets to be queued up for the next free
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* core, i.e. it will return as soon as a
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* core becomes free to accept the first
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* packet, as subsequent ones will be added to
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* the backlog for that core.
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*/
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struct rte_mbuf *pkts[RTE_DISTRIB_BACKLOG_SIZE];
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unsigned i;
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struct rte_distributor_backlog *bl = &d->backlog[wkr];
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for (i = 0; i < bl->count; i++) {
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unsigned idx = (bl->start + i) &
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RTE_DISTRIB_BACKLOG_MASK;
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pkts[i] = (void *)((uintptr_t)(bl->pkts[idx] >>
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RTE_DISTRIB_FLAG_BITS));
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}
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/* recursive call.
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* Note that the tags were set before first level call
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* to rte_distributor_process.
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*/
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rte_distributor_process(d, pkts, i);
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bl->count = bl->start = 0;
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}
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}
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/* this function is called when process() fn is called without any new
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* packets. It goes through all the workers and clears any returned packets
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* to do a partial flush.
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*/
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static int
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process_returns(struct rte_distributor *d)
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{
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unsigned wkr;
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unsigned flushed = 0;
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unsigned ret_start = d->returns.start,
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ret_count = d->returns.count;
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for (wkr = 0; wkr < d->num_workers; wkr++) {
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const int64_t data = d->bufs[wkr].bufptr64;
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uintptr_t oldbuf = 0;
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if (data & RTE_DISTRIB_GET_BUF) {
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flushed++;
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if (d->backlog[wkr].count)
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d->bufs[wkr].bufptr64 =
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backlog_pop(&d->backlog[wkr]);
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else {
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d->bufs[wkr].bufptr64 = RTE_DISTRIB_GET_BUF;
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d->in_flight_tags[wkr] = 0;
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d->in_flight_bitmask &= ~(1UL << wkr);
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}
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oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
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} else if (data & RTE_DISTRIB_RETURN_BUF) {
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handle_worker_shutdown(d, wkr);
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oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
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}
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store_return(oldbuf, d, &ret_start, &ret_count);
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}
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d->returns.start = ret_start;
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d->returns.count = ret_count;
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return flushed;
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}
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/* process a set of packets to distribute them to workers */
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int
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rte_distributor_process(struct rte_distributor *d,
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struct rte_mbuf **mbufs, unsigned num_mbufs)
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{
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unsigned next_idx = 0;
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unsigned wkr = 0;
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struct rte_mbuf *next_mb = NULL;
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int64_t next_value = 0;
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uint32_t new_tag = 0;
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unsigned ret_start = d->returns.start,
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ret_count = d->returns.count;
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if (unlikely(num_mbufs == 0))
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return process_returns(d);
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while (next_idx < num_mbufs || next_mb != NULL) {
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int64_t data = d->bufs[wkr].bufptr64;
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uintptr_t oldbuf = 0;
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if (!next_mb) {
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next_mb = mbufs[next_idx++];
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next_value = (((int64_t)(uintptr_t)next_mb)
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<< RTE_DISTRIB_FLAG_BITS);
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/*
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* User is advocated to set tag vaue for each
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* mbuf before calling rte_distributor_process.
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* User defined tags are used to identify flows,
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* or sessions.
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*/
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new_tag = next_mb->hash.usr;
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/*
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* Note that if RTE_DISTRIB_MAX_WORKERS is larger than 64
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* then the size of match has to be expanded.
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*/
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uint64_t match = 0;
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unsigned i;
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/*
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* to scan for a match use "xor" and "not" to get a 0/1
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* value, then use shifting to merge to single "match"
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* variable, where a one-bit indicates a match for the
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* worker given by the bit-position
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*/
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for (i = 0; i < d->num_workers; i++)
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match |= (!(d->in_flight_tags[i] ^ new_tag)
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<< i);
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/* Only turned-on bits are considered as match */
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match &= d->in_flight_bitmask;
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if (match) {
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next_mb = NULL;
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unsigned worker = __builtin_ctzl(match);
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if (add_to_backlog(&d->backlog[worker],
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next_value) < 0)
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next_idx--;
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}
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}
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if ((data & RTE_DISTRIB_GET_BUF) &&
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(d->backlog[wkr].count || next_mb)) {
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if (d->backlog[wkr].count)
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d->bufs[wkr].bufptr64 =
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backlog_pop(&d->backlog[wkr]);
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else {
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d->bufs[wkr].bufptr64 = next_value;
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d->in_flight_tags[wkr] = new_tag;
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d->in_flight_bitmask |= (1UL << wkr);
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next_mb = NULL;
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}
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oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
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} else if (data & RTE_DISTRIB_RETURN_BUF) {
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handle_worker_shutdown(d, wkr);
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oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
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}
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/* store returns in a circular buffer */
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store_return(oldbuf, d, &ret_start, &ret_count);
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if (++wkr == d->num_workers)
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wkr = 0;
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}
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/* to finish, check all workers for backlog and schedule work for them
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* if they are ready */
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for (wkr = 0; wkr < d->num_workers; wkr++)
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if (d->backlog[wkr].count &&
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(d->bufs[wkr].bufptr64 & RTE_DISTRIB_GET_BUF)) {
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int64_t oldbuf = d->bufs[wkr].bufptr64 >>
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RTE_DISTRIB_FLAG_BITS;
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store_return(oldbuf, d, &ret_start, &ret_count);
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d->bufs[wkr].bufptr64 = backlog_pop(&d->backlog[wkr]);
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}
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d->returns.start = ret_start;
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d->returns.count = ret_count;
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return num_mbufs;
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}
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/* return to the caller, packets returned from workers */
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int
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rte_distributor_returned_pkts(struct rte_distributor *d,
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struct rte_mbuf **mbufs, unsigned max_mbufs)
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{
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struct rte_distributor_returned_pkts *returns = &d->returns;
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unsigned retval = (max_mbufs < returns->count) ?
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max_mbufs : returns->count;
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unsigned i;
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for (i = 0; i < retval; i++) {
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unsigned idx = (returns->start + i) & RTE_DISTRIB_RETURNS_MASK;
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mbufs[i] = returns->mbufs[idx];
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}
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returns->start += i;
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returns->count -= i;
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return retval;
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}
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/* return the number of packets in-flight in a distributor, i.e. packets
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* being workered on or queued up in a backlog. */
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static inline unsigned
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total_outstanding(const struct rte_distributor *d)
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{
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unsigned wkr, total_outstanding;
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total_outstanding = __builtin_popcountl(d->in_flight_bitmask);
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for (wkr = 0; wkr < d->num_workers; wkr++)
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total_outstanding += d->backlog[wkr].count;
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return total_outstanding;
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}
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/* flush the distributor, so that there are no outstanding packets in flight or
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* queued up. */
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int
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rte_distributor_flush(struct rte_distributor *d)
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{
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const unsigned flushed = total_outstanding(d);
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while (total_outstanding(d) > 0)
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rte_distributor_process(d, NULL, 0);
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return flushed;
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}
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/* clears the internal returns array in the distributor */
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void
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rte_distributor_clear_returns(struct rte_distributor *d)
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{
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d->returns.start = d->returns.count = 0;
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#ifndef __OPTIMIZE__
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memset(d->returns.mbufs, 0, sizeof(d->returns.mbufs));
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#endif
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}
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/* creates a distributor instance */
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struct rte_distributor *
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rte_distributor_create(const char *name,
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unsigned socket_id,
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unsigned num_workers)
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{
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struct rte_distributor *d;
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struct rte_distributor_list *distributor_list;
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char mz_name[RTE_MEMZONE_NAMESIZE];
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const struct rte_memzone *mz;
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/* compilation-time checks */
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RTE_BUILD_BUG_ON((sizeof(*d) & RTE_CACHE_LINE_MASK) != 0);
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RTE_BUILD_BUG_ON((RTE_DISTRIB_MAX_WORKERS & 7) != 0);
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RTE_BUILD_BUG_ON(RTE_DISTRIB_MAX_WORKERS >
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sizeof(d->in_flight_bitmask) * CHAR_BIT);
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if (name == NULL || num_workers >= RTE_DISTRIB_MAX_WORKERS) {
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rte_errno = EINVAL;
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return NULL;
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}
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snprintf(mz_name, sizeof(mz_name), RTE_DISTRIB_PREFIX"%s", name);
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mz = rte_memzone_reserve(mz_name, sizeof(*d), socket_id, NO_FLAGS);
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if (mz == NULL) {
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rte_errno = ENOMEM;
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return NULL;
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}
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d = mz->addr;
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snprintf(d->name, sizeof(d->name), "%s", name);
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d->num_workers = num_workers;
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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;
|
|
}
|