Date: Tue, 22 Mar 2016 06:31:39 +0000 (UTC) From: Sepherosa Ziehau <sephe@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r297180 - head/sys/dev/hyperv/netvsc Message-ID: <201603220631.u2M6Vd2G096744@repo.freebsd.org>
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Author: sephe Date: Tue Mar 22 06:31:39 2016 New Revision: 297180 URL: https://svnweb.freebsd.org/changeset/base/297180 Log: hyperv/hn: Reduce TCP segment aggregation limit for multiple RX rings This mainly used to improve ACK timeliness when multiple RX rings are enabled. This value gives the best performance in both Azure and Hyper-V environment, w/ both 10Ge and 40Ge using non-{INVARIANTS,WITNESS} kernel. MFC after: 1 week Sponsored by: Microsoft OSTC Differential Revision: https://reviews.freebsd.org/D5691 Modified: head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Modified: head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c ============================================================================== --- head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Tue Mar 22 06:24:52 2016 (r297179) +++ head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Tue Mar 22 06:31:39 2016 (r297180) @@ -181,6 +181,7 @@ struct hn_txdesc { #define HN_CSUM_ASSIST_WIN8 (CSUM_IP | CSUM_TCP) #define HN_CSUM_ASSIST (CSUM_IP | CSUM_UDP | CSUM_TCP) +#define HN_LRO_LENLIM_MULTIRX_DEF (12 * ETHERMTU) #define HN_LRO_LENLIM_DEF (25 * ETHERMTU) /* YYY 2*MTU is a bit rough, but should be good enough. */ #define HN_LRO_LENLIM_MIN(ifp) (2 * (ifp)->if_mtu) @@ -530,6 +531,21 @@ netvsc_attach(device_t dev) device_printf(dev, "%d TX ring, %d RX ring\n", sc->hn_tx_ring_inuse, sc->hn_rx_ring_inuse); +#if __FreeBSD_version >= 1100099 + if (sc->hn_rx_ring_inuse > 1) { + int i; + + /* + * Reduce TCP segment aggregation limit for multiple + * RX rings to increase ACK timeliness. + */ + for (i = 0; i < sc->hn_rx_ring_inuse; ++i) { + sc->hn_rx_ring[i].hn_lro.lro_length_lim = + HN_LRO_LENLIM_MULTIRX_DEF; + } + } +#endif + if (device_info.link_state == 0) { sc->hn_carrier = 1; }
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