7127e6acf0
Add a last-modified timestamp to each LRO entry and provide an interface to flush all inactive entries. Drivers decide when to flush and what the inactivity threshold should be. Network drivers that process an rx queue to completion can enter a livelock type situation when the rate at which packets are received reaches equilibrium with the rate at which the rx thread is processing them. When this happens the final LRO flush (normally when the rx routine is done) does not occur. Pure ACKs and segments with total payload < 64K can get stuck in an LRO entry. Symptoms are that TCP tx-mostly connections' performance falls off a cliff during heavy, unrelated rx on the interface. Flushing only inactive LRO entries works better than any of these alternates that I tried: - don't LRO pure ACKs - flush _all_ LRO entries periodically (every 'x' microseconds or every 'y' descriptors) - stop rx processing in the driver periodically and schedule remaining work for later. Reviewed by: andre
97 lines
2.9 KiB
C
97 lines
2.9 KiB
C
/*-
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* Copyright (c) 2006, Myricom Inc.
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* Copyright (c) 2008, Intel Corporation.
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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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* 1. 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _TCP_LRO_H_
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#define _TCP_LRO_H_
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#include <sys/time.h>
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struct lro_entry
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{
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SLIST_ENTRY(lro_entry) next;
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struct mbuf *m_head;
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struct mbuf *m_tail;
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union {
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struct ip *ip4;
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struct ip6_hdr *ip6;
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} leip;
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union {
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in_addr_t s_ip4;
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struct in6_addr s_ip6;
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} lesource;
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union {
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in_addr_t d_ip4;
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struct in6_addr d_ip6;
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} ledest;
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uint16_t source_port;
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uint16_t dest_port;
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uint16_t eh_type; /* EthernetHeader type. */
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uint16_t append_cnt;
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uint32_t p_len; /* IP header payload length. */
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uint32_t ulp_csum; /* TCP, etc. checksum. */
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uint32_t next_seq; /* tcp_seq */
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uint32_t ack_seq; /* tcp_seq */
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uint32_t tsval;
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uint32_t tsecr;
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uint16_t window;
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uint16_t timestamp; /* flag, not a TCP hdr field. */
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struct timeval mtime;
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};
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SLIST_HEAD(lro_head, lro_entry);
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#define le_ip4 leip.ip4
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#define le_ip6 leip.ip6
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#define source_ip4 lesource.s_ip4
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#define dest_ip4 ledest.d_ip4
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#define source_ip6 lesource.s_ip6
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#define dest_ip6 ledest.d_ip6
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/* NB: This is part of driver structs. */
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struct lro_ctrl {
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struct ifnet *ifp;
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int lro_queued;
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int lro_flushed;
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int lro_bad_csum;
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int lro_cnt;
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struct lro_head lro_active;
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struct lro_head lro_free;
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};
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int tcp_lro_init(struct lro_ctrl *);
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void tcp_lro_free(struct lro_ctrl *);
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void tcp_lro_flush_inactive(struct lro_ctrl *, const struct timeval *);
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void tcp_lro_flush(struct lro_ctrl *, struct lro_entry *);
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int tcp_lro_rx(struct lro_ctrl *, struct mbuf *, uint32_t);
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#define TCP_LRO_CANNOT -1
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#define TCP_LRO_NOT_SUPPORTED 1
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#endif /* _TCP_LRO_H_ */
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