Sorry the last e-mail had wrong output format.
We got a crash of ovs-vswitchd.I start ovs following the instructions of
INSTALL.DPDK.md, with the ovs master code.In my enironment, there are four cpu
cores, the "real_n_txq" of dpdk port is 1 and "txq_needs_locking" is "true"
...ovs-vsctl add-br br0 -- set bridge br0 datapath_type=netdevovs-vsctl
add-port br0 dpdk0 -- set Interface dpdk0 type=dpdkovs-vsctl add-port br0
dpdkvhost0 -- set Interface dpdkvhost0 type=dpdkvhost
It works, then i bring up a guest and do some tests, a segmentfault happenned
to ovs-vswitchd when I run "iperf3" clients on guest and host at the same
time.guest: iperf client sends tcp packets -> dpdkvhost0 -> OVS -> dpdk0 ->
outsidehost: iperf client sends tcp packets -> br0 -> OVS -> dpdk0 -> outside
The segmentfault like this:Program received signal SIGSEGV, Segmentation
fault.eth_em_xmit_pkts (tx_queue=0x7f623d0f9880, tx_pkts=0x7f623d0ebee8,
nb_pkts=65535) at dpdk-2.0.0/lib/librte_pmd_e1000/em_rxtx.c:436436
ol_flags = tx_pkt->ol_flags;(gdb) bt#0 eth_em_xmit_pkts
(tx_queue=0x7f623d0f9880, tx_pkts=0x7f623d0ebee8, nb_pkts=65535) at
dpdk-2.0.0/lib/librte_pmd_e1000/em_rxtx.c:436#1 0x0000000000625d3d in
rte_eth_tx_burst at
dpdk-2.0.0/x86_64-native-linuxapp-gcc/include/rte_ethdev.h:2572#2
dpdk_queue_flush__ (dev=dev@entry=0x7f623d0f9940, qid=qid@entry=0) at
lib/netdev-dpdk.c:808#3 0x0000000000627324 in dpdk_queue_pkts (cnt=1,
pkts=0x7fff5da5a8f0, qid=0, dev=0x7f623d0f9940) at lib/netdev-dpdk.c:1003#4
dpdk_do_tx_copy (netdev=netdev@entry=0x7f623d0f9940, qid=qid@entry=0,
pkts=pkts@entry=0x7fff5da5ae80, cnt=cnt@entry=1) at lib/netdev-dpdk.c:1073#5
0x0000000000627e96 in netdev_dpdk_send__ (may_steal=<optimized out>, cnt=1,
pkts=0x7fff5da5ae80, qid=0, dev=0x7f623d0f9940) at lib/netdev-dpdk.c:1116#6
netdev_dpdk_eth_send (netdev=0x7f623d0f9940, qid=<optimized out>,
pkts=0x7fff5da5ae80, cnt=1, may_steal=<optimized out>) at lib/netdev-dpdk.c:1169
The traffics of guest and br0 are processing by main thread and pmd thread
seperately. The pkts of br0 are sent by "netdev_dpdk_send__" with lock
"rte_spinlock_lock" via dpdk port, and the pmd main thread processes the
sending direction pkts of dpdk port by dpdk_queue_flush without lock. The carsh
seems to be caused by this.We fixed it with this patch and the segmentfault did
not happen again.The modification does not affect the performance phy to phy
when the txq num is equal to cpu num, we tesed it on server with Intel Xecn
E52630 and 82599 xge nic.I guess it also does not affect the performance of
the opposite condition(not equal) for the "flush_tx" of the txq is "true" and
it will be flushed every time in "dpdk_queue_pkts".We dont clearly kown if
there is better modificaion, some help will be greately appreciated.
------------------------------------------------------------------From:Gray,
Mark D <mark.d.g...@intel.com>Time:2015 Jun 5 (Fri) 22:53To:钢锁0310
<l...@dtdream.com>, d...@openvswitch.com <d...@openvswitch.com>Subject:Re:
[ovs-dev] [PATCH] netdev-dpdk: Do not flush tx queue which is shared
among CPUs since it is always flushed> > When tx queue is shared among CPUS,the
pkts always be flush in> 'netdev_dpdk_eth_send'> So it is unnecessarily for
flushing in netdev_dpdk_rxq_recv Otherwise tx will> be accessed without
lockingAre you seeing a specific bug or is this just to account for a device
withless queues than pmds?> > Signed-off-by: Wei li <l...@dtdream.com>> --->
lib/netdev-dpdk.c | 7 +++++--> 1 file changed, 5 insertions(+), 2
deletions(-)> > diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c index
63243d8..25e3a73> 100644> --- a/lib/netdev-dpdk.c> +++ b/lib/netdev-dpdk.c> @@
-892,8 +892,11 @@ netdev_dpdk_rxq_recv(struct netdev_rxq *rxq_,> struct
dp_packet **packets,> int nb_rx;> > /* There is only one tx queue for
this core. Do not flush other> - * queueus. */> - if (rxq_->queue_id ==
rte_lcore_id()) {> + * queueus.s/queueus/queues> + * Do not flush tx
queue which is shared among CPUs> + * since it is always flushed */> +
if (rxq_->queue_id == rte_lcore_id() &&> +
OVS_LIKELY(!dev->txq_needs_locking)) {> dpdk_queue_flush(dev,
rxq_->queue_id);Do you see any drop in performance in a simple phy-phy case
beforeand after this patch?> }> > --> 1.9.5.msysgit.1> > >
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