Author: sephe Date: Tue Jan 12 01:50:56 2016 New Revision: 293721 URL: https://svnweb.freebsd.org/changeset/base/293721
Log: hyperv/hn: Avoid mbuf cluster allocation, if the packet is small. This one mainly avoids mbuf cluster allocation for TCP ACKs during TCP sending tests. And it gives me ~200Mbps improvement (4.7Gbps -> 4.9Gbps), when running iperf3 TCP sending test w/ 16 connections. While I'm here, nuke the unnecessary zeroing out pkthdr.csum_flags. Reviewed by: adrain Approved by: adrian (mentor) Sponsored by: Microsoft OSTC Differential Revision: https://reviews.freebsd.org/D4853 Modified: head/sys/dev/hyperv/netvsc/hv_net_vsc.h head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Modified: head/sys/dev/hyperv/netvsc/hv_net_vsc.h ============================================================================== --- head/sys/dev/hyperv/netvsc/hv_net_vsc.h Tue Jan 12 01:41:34 2016 (r293720) +++ head/sys/dev/hyperv/netvsc/hv_net_vsc.h Tue Jan 12 01:50:56 2016 (r293721) @@ -1011,6 +1011,7 @@ typedef struct hn_softc { u_long hn_csum_tcp; u_long hn_csum_trusted; u_long hn_lro_tried; + u_long hn_small_pkts; } hn_softc_t; Modified: head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c ============================================================================== --- head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Tue Jan 12 01:41:34 2016 (r293720) +++ head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Tue Jan 12 01:50:56 2016 (r293721) @@ -469,6 +469,8 @@ netvsc_attach(device_t dev) SYSCTL_ADD_ULONG(ctx, child, OID_AUTO, "csum_trusted", CTLFLAG_RW, &sc->hn_csum_trusted, "# of TCP segements that we trust host's csum verification"); + SYSCTL_ADD_ULONG(ctx, child, OID_AUTO, "small_pkts", + CTLFLAG_RW, &sc->hn_small_pkts, "# of small packets received"); if (unit == 0) { struct sysctl_ctx_list *dc_ctx; @@ -1022,35 +1024,38 @@ netvsc_recv(struct hv_device *device_ctx */ if (packet->tot_data_buf_len > (ifp->if_mtu + ETHER_HDR_LEN)) { return (0); - } - - /* - * Get an mbuf with a cluster. For packets 2K or less, - * get a standard 2K cluster. For anything larger, get a - * 4K cluster. Any buffers larger than 4K can cause problems - * if looped around to the Hyper-V TX channel, so avoid them. - */ - size = MCLBYTES; - - if (packet->tot_data_buf_len > MCLBYTES) { - /* 4096 */ - size = MJUMPAGESIZE; - } + } else if (packet->tot_data_buf_len <= MHLEN) { + m_new = m_gethdr(M_NOWAIT, MT_DATA); + if (m_new == NULL) + return (0); + memcpy(mtod(m_new, void *), packet->data, + packet->tot_data_buf_len); + m_new->m_pkthdr.len = m_new->m_len = packet->tot_data_buf_len; + sc->hn_small_pkts++; + } else { + /* + * Get an mbuf with a cluster. For packets 2K or less, + * get a standard 2K cluster. For anything larger, get a + * 4K cluster. Any buffers larger than 4K can cause problems + * if looped around to the Hyper-V TX channel, so avoid them. + */ + size = MCLBYTES; + if (packet->tot_data_buf_len > MCLBYTES) { + /* 4096 */ + size = MJUMPAGESIZE; + } - m_new = m_getjcl(M_NOWAIT, MT_DATA, M_PKTHDR, size); + m_new = m_getjcl(M_NOWAIT, MT_DATA, M_PKTHDR, size); + if (m_new == NULL) { + device_printf(dev, "alloc mbuf failed.\n"); + return (0); + } - if (m_new == NULL) { - device_printf(dev, "alloc mbuf failed.\n"); - return (0); + hv_m_append(m_new, packet->tot_data_buf_len, packet->data); } - - hv_m_append(m_new, packet->tot_data_buf_len, - packet->data); - m_new->m_pkthdr.rcvif = ifp; /* receive side checksum offload */ - m_new->m_pkthdr.csum_flags = 0; if (NULL != csum_info) { /* IP csum offload */ if (csum_info->receive.ip_csum_succeeded) { _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
