svn commit: r271946 - in head/sys: dev/oce dev/vmware/vmxnet3 dev/xen/netfront kern net netinet ofed/drivers/net/mlx4 sys
Lawrence Stewart
lstewart at freebsd.org
Mon Oct 13 14:26:01 UTC 2014
Hi Hans,
I have questions and feedback regarding this patch that I was hoping to
work through with you. Some general points are below and then context
specific points are inline with the patch further down.
- Is QinQ support affected by this change?
- There are some style(9) nits throughout that might be tweaked if parts
of this patch end up being reworked e.g. new lines in
if_hw_tsomax_common() and if_hw_tsomax_update()
On 09/22/14 18:27, Hans Petter Selasky wrote:
> Author: hselasky
> Date: Mon Sep 22 08:27:27 2014
> New Revision: 271946
> URL: http://svnweb.freebsd.org/changeset/base/271946
>
> Log:
> Improve transmit sending offload, TSO, algorithm in general.
>
> The current TSO limitation feature only takes the total number of
> bytes in an mbuf chain into account and does not limit by the number
> of mbufs in a chain. Some kinds of hardware is limited by two
> factors. One is the fragment length and the second is the fragment
> count. Both of these limits need to be taken into account when doing
> TSO. Else some kinds of hardware might have to drop completely valid
> mbuf chains because they cannot loaded into the given hardware's DMA
> engine. The new way of doing TSO limitation has been made backwards
> compatible as input from other FreeBSD developers and will use
> defaults for values not set.
>
> Reviewed by: adrian, rmacklem
> Sponsored by: Mellanox Technologies
> MFC after: 1 week
>
> Modified:
> head/sys/dev/oce/oce_if.c
> head/sys/dev/oce/oce_if.h
> head/sys/dev/vmware/vmxnet3/if_vmx.c
> head/sys/dev/vmware/vmxnet3/if_vmxvar.h
> head/sys/dev/xen/netfront/netfront.c
> head/sys/kern/uipc_sockbuf.c
> head/sys/net/if.c
> head/sys/net/if_lagg.c
> head/sys/net/if_var.h
> head/sys/net/if_vlan.c
> head/sys/netinet/tcp_input.c
> head/sys/netinet/tcp_output.c
> head/sys/netinet/tcp_subr.c
> head/sys/netinet/tcp_var.h
> head/sys/ofed/drivers/net/mlx4/en_netdev.c
> head/sys/sys/sockbuf.h
>
> Modified: head/sys/dev/oce/oce_if.c
> ==============================================================================
> --- head/sys/dev/oce/oce_if.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/dev/oce/oce_if.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -1731,7 +1731,9 @@ oce_attach_ifp(POCE_SOFTC sc)
> sc->ifp->if_baudrate = IF_Gbps(10);
>
> #if __FreeBSD_version >= 1000000
> - sc->ifp->if_hw_tsomax = OCE_MAX_TSO_SIZE;
> + sc->ifp->if_hw_tsomax = 65536 - (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN);
> + sc->ifp->if_hw_tsomaxsegcount = OCE_MAX_TX_ELEMENTS;
> + sc->ifp->if_hw_tsomaxsegsize = 4096;
> #endif
>
> ether_ifattach(sc->ifp, sc->macaddr.mac_addr);
>
I don't like the use of the 65536 magic number here and throughout the
driver changes. Also, should it be 65536 or IP_MAXPACKET (65535)?
> Modified: head/sys/dev/oce/oce_if.h
> ==============================================================================
> --- head/sys/dev/oce/oce_if.h Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/dev/oce/oce_if.h Mon Sep 22 08:27:27 2014 (r271946)
> @@ -152,7 +152,6 @@ extern int mp_ncpus; /* system's total
> #define OCE_MAX_TX_ELEMENTS 29
> #define OCE_MAX_TX_DESC 1024
> #define OCE_MAX_TX_SIZE 65535
> -#define OCE_MAX_TSO_SIZE (65535 - ETHER_HDR_LEN)
> #define OCE_MAX_RX_SIZE 4096
> #define OCE_MAX_RQ_POSTS 255
> #define OCE_DEFAULT_PROMISCUOUS 0
>
> Modified: head/sys/dev/vmware/vmxnet3/if_vmx.c
> ==============================================================================
> --- head/sys/dev/vmware/vmxnet3/if_vmx.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/dev/vmware/vmxnet3/if_vmx.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -1722,7 +1722,9 @@ vmxnet3_setup_interface(struct vmxnet3_s
> ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
> ifp->if_init = vmxnet3_init;
> ifp->if_ioctl = vmxnet3_ioctl;
> - ifp->if_hw_tsomax = VMXNET3_TSO_MAXSIZE;
> + ifp->if_hw_tsomax = 65536 - (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN);
> + ifp->if_hw_tsomaxsegcount = VMXNET3_TX_MAXSEGS;
> + ifp->if_hw_tsomaxsegsize = VMXNET3_TX_MAXSEGSIZE;
>
> #ifdef VMXNET3_LEGACY_TX
> ifp->if_start = vmxnet3_start;
>
> Modified: head/sys/dev/vmware/vmxnet3/if_vmxvar.h
> ==============================================================================
> --- head/sys/dev/vmware/vmxnet3/if_vmxvar.h Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/dev/vmware/vmxnet3/if_vmxvar.h Mon Sep 22 08:27:27 2014 (r271946)
> @@ -277,8 +277,6 @@ struct vmxnet3_softc {
> */
> #define VMXNET3_TX_MAXSEGS 32
> #define VMXNET3_TX_MAXSIZE (VMXNET3_TX_MAXSEGS * MCLBYTES)
> -#define VMXNET3_TSO_MAXSIZE \
> - (VMXNET3_TX_MAXSIZE - sizeof(struct ether_vlan_header))
>
> /*
> * Maximum support Tx segments size. The length field in the
>
> Modified: head/sys/dev/xen/netfront/netfront.c
> ==============================================================================
> --- head/sys/dev/xen/netfront/netfront.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/dev/xen/netfront/netfront.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -134,7 +134,6 @@ static const int MODPARM_rx_flip = 0;
> * to mirror the Linux MAX_SKB_FRAGS constant.
> */
> #define MAX_TX_REQ_FRAGS (65536 / PAGE_SIZE + 2)
> -#define NF_TSO_MAXBURST ((IP_MAXPACKET / PAGE_SIZE) * MCLBYTES)
>
> #define RX_COPY_THRESHOLD 256
>
> @@ -2102,7 +2101,9 @@ create_netdev(device_t dev)
>
> ifp->if_hwassist = XN_CSUM_FEATURES;
> ifp->if_capabilities = IFCAP_HWCSUM;
> - ifp->if_hw_tsomax = NF_TSO_MAXBURST;
> + ifp->if_hw_tsomax = 65536 - (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN);
> + ifp->if_hw_tsomaxsegcount = MAX_TX_REQ_FRAGS;
> + ifp->if_hw_tsomaxsegsize = PAGE_SIZE;
>
> ether_ifattach(ifp, np->mac);
> callout_init(&np->xn_stat_ch, CALLOUT_MPSAFE);
>
> Modified: head/sys/kern/uipc_sockbuf.c
> ==============================================================================
> --- head/sys/kern/uipc_sockbuf.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/kern/uipc_sockbuf.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -1015,6 +1015,37 @@ sbsndptr(struct sockbuf *sb, u_int off,
> }
>
> /*
> + * Return the first mbuf and the mbuf data offset for the provided
> + * send offset without changing the "sb_sndptroff" field.
> + */
> +struct mbuf *
> +sbsndmbuf(struct sockbuf *sb, u_int off, u_int *moff)
> +{
> + struct mbuf *m;
> +
> + KASSERT(sb->sb_mb != NULL, ("%s: sb_mb is NULL", __func__));
> +
> + /*
> + * If the "off" is below the stored offset, which happens on
> + * retransmits, just use "sb_mb":
> + */
> + if (sb->sb_sndptr == NULL || sb->sb_sndptroff > off) {
> + m = sb->sb_mb;
> + } else {
> + m = sb->sb_sndptr;
> + off -= sb->sb_sndptroff;
> + }
> + while (off > 0 && m != NULL) {
> + if (off < m->m_len)
> + break;
> + off -= m->m_len;
> + m = m->m_next;
> + }
> + *moff = off;
> + return (m);
> +}
> +
> +/*
> * Drop a record off the front of a sockbuf and move the next record to the
> * front.
> */
>
> Modified: head/sys/net/if.c
> ==============================================================================
> --- head/sys/net/if.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/net/if.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -584,6 +584,57 @@ if_attach(struct ifnet *ifp)
> if_attach_internal(ifp, 0);
> }
>
> +/*
> + * Compute the least common TSO limit.
> + */
> +void
> +if_hw_tsomax_common(if_t ifp, struct ifnet_hw_tsomax *pmax)
> +{
> + /*
> + * 1) If there is no limit currently, take the limit from
> + * the network adapter.
> + *
> + * 2) If the network adapter has a limit below the current
> + * limit, apply it.
> + */
> + if (pmax->tsomaxbytes == 0 || (ifp->if_hw_tsomax != 0 &&
> + ifp->if_hw_tsomax < pmax->tsomaxbytes)) {
> + pmax->tsomaxbytes = ifp->if_hw_tsomax;
> + }
> + if (pmax->tsomaxsegcount == 0 || (ifp->if_hw_tsomaxsegcount != 0 &&
> + ifp->if_hw_tsomaxsegcount < pmax->tsomaxsegcount)) {
> + pmax->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
> + }
> + if (pmax->tsomaxsegsize == 0 || (ifp->if_hw_tsomaxsegsize != 0 &&
> + ifp->if_hw_tsomaxsegsize < pmax->tsomaxsegsize)) {
> + pmax->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
> + }
> +}
> +
> +/*
> + * Update TSO limit of a network adapter.
> + *
> + * Returns zero if no change. Else non-zero.
> + */
> +int
> +if_hw_tsomax_update(if_t ifp, struct ifnet_hw_tsomax *pmax)
> +{
> + int retval = 0;
> + if (ifp->if_hw_tsomax != pmax->tsomaxbytes) {
> + ifp->if_hw_tsomax = pmax->tsomaxbytes;
> + retval++;
> + }
> + if (ifp->if_hw_tsomaxsegsize != pmax->tsomaxsegsize) {
> + ifp->if_hw_tsomaxsegsize = pmax->tsomaxsegsize;
> + retval++;
> + }
> + if (ifp->if_hw_tsomaxsegcount != pmax->tsomaxsegcount) {
> + ifp->if_hw_tsomaxsegcount = pmax->tsomaxsegcount;
> + retval++;
> + }
> + return (retval);
> +}
> +
> static void
> if_attach_internal(struct ifnet *ifp, int vmove)
> {
> @@ -659,13 +710,36 @@ if_attach_internal(struct ifnet *ifp, in
> ifp->if_broadcastaddr = NULL;
>
> #if defined(INET) || defined(INET6)
> - /* Initialize to max value. */
> - if (ifp->if_hw_tsomax == 0)
> - ifp->if_hw_tsomax = min(IP_MAXPACKET, 32 * MCLBYTES -
> + /* Use defaults for TSO, if nothing is set */
> + if (ifp->if_hw_tsomax == 0 &&
> + ifp->if_hw_tsomaxsegcount == 0 &&
> + ifp->if_hw_tsomaxsegsize == 0) {
> + /*
> + * The TSO defaults needs to be such that an
> + * NFS mbuf list of 35 mbufs totalling just
> + * below 64K works and that a chain of mbufs
> + * can be defragged into at most 32 segments:
> + */
> + ifp->if_hw_tsomax = min(IP_MAXPACKET, (32 * MCLBYTES) -
> (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN));
> - KASSERT(ifp->if_hw_tsomax <= IP_MAXPACKET &&
> - ifp->if_hw_tsomax >= IP_MAXPACKET / 8,
> - ("%s: tsomax outside of range", __func__));
> + ifp->if_hw_tsomaxsegcount = 35;
> + ifp->if_hw_tsomaxsegsize = 2048; /* 2K */
> +
> + /* XXX some drivers set IFCAP_TSO after ethernet attach */
> + if (ifp->if_capabilities & IFCAP_TSO) {
> + if_printf(ifp, "Using defaults for TSO: %u/%u/%u\n",
> + ifp->if_hw_tsomax,
> + ifp->if_hw_tsomaxsegcount,
> + ifp->if_hw_tsomaxsegsize);
> + }
> + }
> + /*
> + * If the "if_hw_tsomax" limit is set, check if it is
> + * too small:
> + */
> + KASSERT(ifp->if_hw_tsomax == 0 ||
> + ifp->if_hw_tsomax >= (IP_MAXPACKET / 8),
> + ("%s: if_hw_tsomax is outside of range", __func__));
I don't understand the second condition of the KASSERT i.e.
"ifp->if_hw_tsomax >= (IP_MAXPACKET / 8)"
> #endif
> }
> #ifdef VIMAGE
>
> Modified: head/sys/net/if_lagg.c
> ==============================================================================
> --- head/sys/net/if_lagg.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/net/if_lagg.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -454,23 +454,18 @@ lagg_capabilities(struct lagg_softc *sc)
> struct lagg_port *lp;
> int cap = ~0, ena = ~0;
> u_long hwa = ~0UL;
> -#if defined(INET) || defined(INET6)
> - u_int hw_tsomax = IP_MAXPACKET; /* Initialize to the maximum value. */
> -#else
> - u_int hw_tsomax = ~0; /* if_hw_tsomax is only for INET/INET6, but.. */
> -#endif
> + struct ifnet_hw_tsomax hw_tsomax;
>
> LAGG_WLOCK_ASSERT(sc);
>
> + memset(&hw_tsomax, 0, sizeof(hw_tsomax));
> +
> /* Get capabilities from the lagg ports */
> SLIST_FOREACH(lp, &sc->sc_ports, lp_entries) {
> cap &= lp->lp_ifp->if_capabilities;
> ena &= lp->lp_ifp->if_capenable;
> hwa &= lp->lp_ifp->if_hwassist;
> - /* Set to the minimum value of the lagg ports. */
> - if (lp->lp_ifp->if_hw_tsomax < hw_tsomax &&
> - lp->lp_ifp->if_hw_tsomax > 0)
> - hw_tsomax = lp->lp_ifp->if_hw_tsomax;
> + if_hw_tsomax_common(lp->lp_ifp, &hw_tsomax);
> }
> cap = (cap == ~0 ? 0 : cap);
> ena = (ena == ~0 ? 0 : ena);
> @@ -479,11 +474,10 @@ lagg_capabilities(struct lagg_softc *sc)
> if (sc->sc_ifp->if_capabilities != cap ||
> sc->sc_ifp->if_capenable != ena ||
> sc->sc_ifp->if_hwassist != hwa ||
> - sc->sc_ifp->if_hw_tsomax != hw_tsomax) {
> + if_hw_tsomax_update(sc->sc_ifp, &hw_tsomax) != 0) {
> sc->sc_ifp->if_capabilities = cap;
> sc->sc_ifp->if_capenable = ena;
> sc->sc_ifp->if_hwassist = hwa;
> - sc->sc_ifp->if_hw_tsomax = hw_tsomax;
> getmicrotime(&sc->sc_ifp->if_lastchange);
>
> if (sc->sc_ifflags & IFF_DEBUG)
>
> Modified: head/sys/net/if_var.h
> ==============================================================================
> --- head/sys/net/if_var.h Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/net/if_var.h Mon Sep 22 08:27:27 2014 (r271946)
> @@ -119,6 +119,12 @@ typedef void (*if_qflush_fn_t)(if_t);
> typedef int (*if_transmit_fn_t)(if_t, struct mbuf *);
> typedef uint64_t (*if_get_counter_t)(if_t, ift_counter);
>
> +struct ifnet_hw_tsomax {
> + u_int tsomaxbytes; /* TSO total burst length limit in bytes */
> + u_int tsomaxsegcount; /* TSO maximum segment count */
> + u_int tsomaxsegsize; /* TSO maximum segment size in bytes */
> +};
> +
> /*
> * Structure defining a network interface.
> *
> @@ -222,10 +228,11 @@ struct ifnet {
> if_get_counter_t if_get_counter; /* get counter values */
>
> /* Stuff that's only temporary and doesn't belong here. */
> - u_int if_hw_tsomax; /* tso burst length limit, the minimum
> - * is (IP_MAXPACKET / 8).
> - * XXXAO: Have to find a better place
> - * for it eventually. */
> + u_int if_hw_tsomax; /* TSO total burst length
> + * limit in bytes. A value of
> + * zero means no limit. Have
> + * to find a better place for
> + * it eventually. */
> /*
> * Old, racy and expensive statistics, should not be used in
> * new drivers.
> @@ -243,6 +250,10 @@ struct ifnet {
> uint64_t if_oqdrops; /* dropped on output */
> uint64_t if_noproto; /* destined for unsupported protocol */
>
> + /* TSO fields for segment limits. If a field is zero below, there is no limit. */
> + u_int if_hw_tsomaxsegcount; /* TSO maximum segment count */
> + u_int if_hw_tsomaxsegsize; /* TSO maximum segment size in bytes */
> +
> /*
> * Spare fields to be added before branching a stable branch, so
> * that structure can be enhanced without changing the kernel
> @@ -596,5 +607,9 @@ struct mbuf* drbr_dequeue_drv(if_t ifp,
> int drbr_needs_enqueue_drv(if_t ifp, struct buf_ring *br);
> int drbr_enqueue_drv(if_t ifp, struct buf_ring *br, struct mbuf *m);
>
> +/* TSO */
> +void if_hw_tsomax_common(if_t ifp, struct ifnet_hw_tsomax *);
> +int if_hw_tsomax_update(if_t ifp, struct ifnet_hw_tsomax *);
> +
> #endif /* _KERNEL */
> #endif /* !_NET_IF_VAR_H_ */
>
> Modified: head/sys/net/if_vlan.c
> ==============================================================================
> --- head/sys/net/if_vlan.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/net/if_vlan.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -1536,6 +1536,7 @@ vlan_capabilities(struct ifvlan *ifv)
> {
> struct ifnet *p = PARENT(ifv);
> struct ifnet *ifp = ifv->ifv_ifp;
> + struct ifnet_hw_tsomax hw_tsomax;
>
> TRUNK_LOCK_ASSERT(TRUNK(ifv));
>
> @@ -1562,8 +1563,9 @@ vlan_capabilities(struct ifvlan *ifv)
> * propagate the hardware-assisted flag. TSO on VLANs
> * does not necessarily require hardware VLAN tagging.
> */
> - if (p->if_hw_tsomax > 0)
> - ifp->if_hw_tsomax = p->if_hw_tsomax;
> + memset(&hw_tsomax, 0, sizeof(hw_tsomax));
> + if_hw_tsomax_common(p, &hw_tsomax);
> + if_hw_tsomax_update(ifp, &hw_tsomax);
> if (p->if_capabilities & IFCAP_VLAN_HWTSO)
> ifp->if_capabilities |= p->if_capabilities & IFCAP_TSO;
> if (p->if_capenable & IFCAP_VLAN_HWTSO) {
>
> Modified: head/sys/netinet/tcp_input.c
> ==============================================================================
> --- head/sys/netinet/tcp_input.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/netinet/tcp_input.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -3591,6 +3591,8 @@ tcp_mss(struct tcpcb *tp, int offer)
> if (cap.ifcap & CSUM_TSO) {
> tp->t_flags |= TF_TSO;
> tp->t_tsomax = cap.tsomax;
> + tp->t_tsomaxsegcount = cap.tsomaxsegcount;
> + tp->t_tsomaxsegsize = cap.tsomaxsegsize;
> }
> }
>
>
> Modified: head/sys/netinet/tcp_output.c
> ==============================================================================
> --- head/sys/netinet/tcp_output.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/netinet/tcp_output.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -767,28 +767,113 @@ send:
> flags &= ~TH_FIN;
>
> if (tso) {
> + u_int if_hw_tsomax;
> + u_int if_hw_tsomaxsegcount;
> + u_int if_hw_tsomaxsegsize;
> + struct mbuf *mb;
> + u_int moff;
> + int max_len;
> +
> + /* extract TSO information */
> + if_hw_tsomax = tp->t_tsomax;
> + if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
> + if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
> +
> + /*
> + * Limit a TSO burst to prevent it from
> + * overflowing or exceeding the maximum length
> + * allowed by the network interface:
> + */
This appears to have been moved from just below for no apparent reason?
> KASSERT(ipoptlen == 0,
> ("%s: TSO can't do IP options", __func__));
>
> /*
> - * Limit a burst to t_tsomax minus IP,
> - * TCP and options length to keep ip->ip_len
> - * from overflowing or exceeding the maximum
> - * length allowed by the network interface.
> + * Check if we should limit by maximum payload
> + * length:
> */
> - if (len > tp->t_tsomax - hdrlen) {
> - len = tp->t_tsomax - hdrlen;
> - sendalot = 1;
> + if (if_hw_tsomax != 0) {
> + /* compute maximum TSO length */
> + max_len = (if_hw_tsomax - hdrlen);
> + if (max_len <= 0) {
> + len = 0;
Is the "max_len < 0" check useful? If "if_hw_tsomax - hdrlen" is leq 0,
then TSO is unusable on the interface is it not?
> + } else if (len > (u_int)max_len) {
> + sendalot = 1;
> + len = (u_int)max_len;
> + }
Why is max_len cast to u_int for comparison/assignment with/to len here
and elsewhere?
> + }
> +
> + /*
> + * Check if we should limit by maximum segment
> + * size and count:
> + */
> + if (if_hw_tsomaxsegcount != 0 && if_hw_tsomaxsegsize != 0) {
Is it conceivable a driver may want to limit by maxsegcount or
maxsegsize, but not by both?
In the event if_hw_tsomax, if_hw_tsomaxsegcount and if_hw_tsomaxsegsize
are non-zero, the calculation of len related to if_hw_tsomax will be
overridden to a potentially incorrect value in this block.
> + max_len = 0;
> + mb = sbsndmbuf(&so->so_snd, off, &moff);
> +
> + while (mb != NULL && (u_int)max_len < len) {
> + u_int cur_length;
> + u_int cur_frags;
> +
> + /*
> + * Get length of mbuf fragment
> + * and how many hardware
> + * frags, rounded up, it would
> + * use:
> + */
> + cur_length = (mb->m_len - moff);
> + cur_frags = (cur_length + if_hw_tsomaxsegsize -
> + 1) / if_hw_tsomaxsegsize;
> +
> + /* Handle special case: Zero Length Mbuf */
> + if (cur_frags == 0)
> + cur_frags = 1;
> +
> + /*
> + * Check if the fragment limit
> + * will be reached or
> + * exceeded:
> + */
> + if (cur_frags >= if_hw_tsomaxsegcount) {
> + max_len += min(cur_length,
> + if_hw_tsomaxsegcount *
> + if_hw_tsomaxsegsize);
> + break;
> + }
> + max_len += cur_length;
> + if_hw_tsomaxsegcount -= cur_frags;
> + moff = 0;
> + mb = mb->m_next;
> + }
> + if (max_len <= 0) {
> + len = 0;
> + } else if (len > (u_int)max_len) {
> + sendalot = 1;
> + len = (u_int)max_len;
> + }
> }
>
> /*
> * Prevent the last segment from being
> - * fractional unless the send sockbuf can
> - * be emptied.
> + * fractional unless the send sockbuf can be
> + * emptied:
> + */
> + max_len = (tp->t_maxopd - optlen);
> + if ((off + len) < so->so_snd.sb_cc) {
> + moff = len % (u_int)max_len;
> + if (moff != 0) {
> + len -= moff;
> + sendalot = 1;
> + }
> + }
> +
> + /*
> + * In case there are too many small fragments
> + * don't use TSO:
> */
> - if (sendalot && off + len < so->so_snd.sb_cc) {
> - len -= len % (tp->t_maxopd - optlen);
> + if (len <= (u_int)max_len) {
> + len = (u_int)max_len;
> sendalot = 1;
> + tso = 0;
> }
I don't quite understand the "too many small fragements" check.
>
> /*
>
> Modified: head/sys/netinet/tcp_subr.c
> ==============================================================================
> --- head/sys/netinet/tcp_subr.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/netinet/tcp_subr.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -1819,6 +1819,8 @@ tcp_maxmtu(struct in_conninfo *inc, stru
> ifp->if_hwassist & CSUM_TSO) {
> cap->ifcap |= CSUM_TSO;
> cap->tsomax = ifp->if_hw_tsomax;
> + cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
> + cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
> }
> }
> RTFREE(sro.ro_rt);
> @@ -1858,6 +1860,8 @@ tcp_maxmtu6(struct in_conninfo *inc, str
> ifp->if_hwassist & CSUM_TSO) {
> cap->ifcap |= CSUM_TSO;
> cap->tsomax = ifp->if_hw_tsomax;
> + cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
> + cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
> }
> }
> RTFREE(sro6.ro_rt);
>
> Modified: head/sys/netinet/tcp_var.h
> ==============================================================================
> --- head/sys/netinet/tcp_var.h Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/netinet/tcp_var.h Mon Sep 22 08:27:27 2014 (r271946)
> @@ -199,9 +199,12 @@ struct tcpcb {
> u_int t_keepintvl; /* interval between keepalives */
> u_int t_keepcnt; /* number of keepalives before close */
>
> - u_int t_tsomax; /* tso burst length limit */
> + u_int t_tsomax; /* TSO total burst length limit in bytes */
> +
> + uint32_t t_ispare[6]; /* 5 UTO, 1 TBD */
> + uint32_t t_tsomaxsegcount; /* TSO maximum segment count */
> + uint32_t t_tsomaxsegsize; /* TSO maximum segment size in bytes */
>
> - uint32_t t_ispare[8]; /* 5 UTO, 3 TBD */
> void *t_pspare2[4]; /* 1 TCP_SIGNATURE, 3 TBD */
> uint64_t _pad[6]; /* 6 TBD (1-2 CC/RTT?) */
> };
I don't think the patch for head should be consuming the spares in
struct tcpcb. We generally only consume spares when MFCing to stable
branches, leaving the spares intact on the head branch.
> @@ -324,6 +327,8 @@ struct hc_metrics_lite { /* must stay in
> struct tcp_ifcap {
> int ifcap;
> u_int tsomax;
> + u_int tsomaxsegcount;
> + u_int tsomaxsegsize;
> };
>
> #ifndef _NETINET_IN_PCB_H_
>
> Modified: head/sys/ofed/drivers/net/mlx4/en_netdev.c
> ==============================================================================
> --- head/sys/ofed/drivers/net/mlx4/en_netdev.c Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/ofed/drivers/net/mlx4/en_netdev.c Mon Sep 22 08:27:27 2014 (r271946)
> @@ -673,6 +673,11 @@ int mlx4_en_do_start_port(struct net_dev
> else
> priv->rx_csum = 0;
>
> + /* set TSO limits so that we don't have to drop TX packets */
> + dev->if_hw_tsomax = 65536 - (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN);
> + dev->if_hw_tsomaxsegcount = 16;
> + dev->if_hw_tsomaxsegsize = 65536; /* XXX can do up to 4GByte */
> +
> err = mlx4_wol_read(priv->mdev->dev, &config, priv->port);
> if (err) {
> en_err(priv, "Failed to get WoL info, unable to modify\n");
>
> Modified: head/sys/sys/sockbuf.h
> ==============================================================================
> --- head/sys/sys/sockbuf.h Mon Sep 22 07:59:25 2014 (r271945)
> +++ head/sys/sys/sockbuf.h Mon Sep 22 08:27:27 2014 (r271946)
> @@ -158,6 +158,8 @@ int sbreserve_locked(struct sockbuf *sb,
> struct thread *td);
> struct mbuf *
> sbsndptr(struct sockbuf *sb, u_int off, u_int len, u_int *moff);
> +struct mbuf *
> + sbsndmbuf(struct sockbuf *sb, u_int off, u_int *moff);
> void sbtoxsockbuf(struct sockbuf *sb, struct xsockbuf *xsb);
> int sbwait(struct sockbuf *sb);
> int sblock(struct sockbuf *sb, int flags);
>
That's the initial list of things I noticed.
Cheers,
Lawrence
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