d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Only chain non-LRO mbufs when LRO is not possible

Browse Source 
Preserve packet order between tcp_lro_rx() and if_input() to avoid
creating extra corner cases. If no packets can be LROed, combine them
into one chain for submission via if_input(). If any packet can
potentially be LROed however, retain old behaviour and call if_input()
for each packet.

This should keep the 12% improvement for small packet forwarding intact,
but mostly avoids impacting the LRO case.

Reviewed by:	cem, sbruno
Approved by:	sbruno (mentor)
Sponsored by:	Limelight Networks
Differential Revision:	https://reviews.freebsd.org/D12876
This commit is contained in:
Stephen Hurd 2017-11-06 16:23:21 +00:00
parent da86af2815
commit 35e4e998d8
1 changed files with 64 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

70
sys/net/iflib.c
View File

@ -59,6 +59,7 @@ __FBSDID("$FreeBSD$");
#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/mp_ring.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
@ -68,6 +69,8 @@ __FBSDID("$FreeBSD$");
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/tcp.h>
#include <netinet/ip_var.h>
#include <netinet6/ip6_var.h>
#include <machine/bus.h>
#include <machine/in_cksum.h>
@ -2463,6 +2466,47 @@ iflib_rxd_pkt_get(iflib_rxq_t rxq, if_rxd_info_t ri)
return (m);
}
#if defined(INET6) || defined(INET)
/*
* Returns true if it's possible this packet could be LROed.
* if it returns false, it is guaranteed that tcp_lro_rx()
* would not return zero.
*/
static bool
iflib_check_lro_possible(struct lro_ctrl *lc, struct mbuf *m)
{
struct ether_header *eh;
uint16_t eh_type;
eh = mtod(m, struct ether_header *);
eh_type = ntohs(eh->ether_type);
switch (eh_type) {
case ETHERTYPE_IPV6:
{
CURVNET_SET(lc->ifp->if_vnet);
if (VNET(ip6_forwarding) == 0) {
CURVNET_RESTORE();
return true;
}
CURVNET_RESTORE();
break;
}
case ETHERTYPE_IP:
{
CURVNET_SET(lc->ifp->if_vnet);
if (VNET(ipforwarding) == 0) {
CURVNET_RESTORE();
return true;
}
CURVNET_RESTORE();
break;
}
}
return false;
}
#endif
static bool
iflib_rxeof(iflib_rxq_t rxq, qidx_t budget)
{
@ -2476,6 +2520,7 @@ iflib_rxeof(iflib_rxq_t rxq, qidx_t budget)
iflib_fl_t fl;
struct ifnet *ifp;
int lro_enabled;
bool lro_possible = false;
/*
* XXX early demux data packets so that if_input processing only handles
@ -2555,8 +2600,6 @@ iflib_rxeof(iflib_rxq_t rxq, qidx_t budget)
mt = mf = NULL;
while (mh != NULL) {
m = mh;
if (mf == NULL)
mf = m;
mh = mh->m_nextpkt;
m->m_nextpkt = NULL;
#ifndef __NO_STRICT_ALIGNMENT
@ -2566,12 +2609,27 @@ iflib_rxeof(iflib_rxq_t rxq, qidx_t budget)
rx_bytes += m->m_pkthdr.len;
rx_pkts++;
#if defined(INET6) || defined(INET)
if (lro_enabled && tcp_lro_rx(&rxq->ifr_lc, m, 0) == 0) {
if (mf == m)
mf = NULL;
continue;
if (lro_enabled) {
if (!lro_possible) {
lro_possible = iflib_check_lro_possible(&rxq->ifr_lc, m);
if (lro_possible && mf != NULL) {
ifp->if_input(ifp, mf);
DBG_COUNTER_INC(rx_if_input);
mt = mf = NULL;
}
}
if (lro_possible && tcp_lro_rx(&rxq->ifr_lc, m, 0) == 0)
continue;
}
#endif
if (lro_possible) {
ifp->if_input(ifp, m);
DBG_COUNTER_INC(rx_if_input);
continue;
}
if (mf == NULL)
mf = m;
if (mt != NULL)
mt->m_nextpkt = m;
mt = m;