Date: Tue, 5 Jul 2011 18:43:54 +0000 (UTC) From: Colin Percival <cperciva@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r223797 - head/sys/netinet Message-ID: <201107051843.p65IhsKk080969@svn.freebsd.org>
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Author: cperciva Date: Tue Jul 5 18:43:54 2011 New Revision: 223797 URL: http://svn.freebsd.org/changeset/base/223797 Log: Don't allow lro->len to exceed 65535, as this will result in overflow when len is inserted back into the synthetic IP packet and cause a multiple of 2^16 bytes of TCP "packet loss". This improves Linux->FreeBSD netperf bandwidth by a factor of 300 in testing on Amazon EC2. Reviewed by: jfv MFC after: 2 weeks Modified: head/sys/netinet/tcp_lro.c Modified: head/sys/netinet/tcp_lro.c ============================================================================== --- head/sys/netinet/tcp_lro.c Tue Jul 5 18:42:10 2011 (r223796) +++ head/sys/netinet/tcp_lro.c Tue Jul 5 18:43:54 2011 (r223797) @@ -277,6 +277,14 @@ tcp_lro_rx(struct lro_ctrl *cntl, struct lro->dest_port == tcp->th_dport && lro->source_ip == ip->ip_src.s_addr && lro->dest_ip == ip->ip_dst.s_addr) { + /* Flush now if appending will result in overflow. */ + if (lro->len > (65535 - tcp_data_len)) { + SLIST_REMOVE(&cntl->lro_active, lro, + lro_entry, next); + tcp_lro_flush(cntl, lro); + break; + } + /* Try to append it */ if (__predict_false(seq != lro->next_seq ||
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