UDP Sockets

Onload User Guide (UG1586)

Document ID

UG1586

Release Date

2023-07-31

Revision

1.2 English

The following table shows typical output for a UDP socket

Table 1. Stackdump Output: UDP Socket
Sample Output	Description
`UDP`	Socket configuration:
`4:1`	Stack:socket id.
`lcl=192.168.1.2:38142`	Local ip:port address.
`rmt=192.168.1.1:42638`	Remote ip:port address.
`UDP`	Connection is UDP.
`lock: 20000000 LOCKED`	Internal socket lock status, as a hexadecimal number, followed by status names including: `LOCKED` `CONTENDED.`
`rx_wake=000e69b0`	Internal sequence value that is incremented each time a receive queue is ‘woken’. `(RQ)` indicates that a wake has been requested.
`tx_wake=000e69b1`	Internal sequence value that is incremented each time a transmit queue is ‘woken’. `(RQ)` indicates that a wake has been requested.
`flags:`	Flags (if any), including: `WK_TX`, `WK_RX` `TCP_PP` `ORPH` `ACCEPTQ` `DEFERRED` `AVOID_INT` `O_ASYNC`, `O_NONBLOCK`, `O_NDELAY`, `O_APPEND`, `O_CLOEXEC` `CACHE`, `PASSIVE_CACHE`, `CACHE_NO_FD` `OS_BACKED` `NONB_UNSYNCED.`
`ul_poll:`	User-level `poll()`:
`0 spin cycles`	in spin cycles
`0 (usec)`	in μs.
`uid=0`	User id that owns this socket.
`s_flags: FILTER`	Socket flags, including: `CORK` `SHUTRD`, `SHUTWR` `TCP_NODELAY` `ACK` `REUSE` `KALIVE` `BCAST` `OOBIN` `LINGER` `DONTROUTE` `FILTER` `BOUND`, `ABOUND`, `PBOUND` `SNDBUF`, `RCVBUF` `SW_FILTER_FULL` `TRANSPARENT` `SCALACTIVE`, `SCALPASSIVE` `MAC_FILTER` `REUSEPORT` `BOUND_ALIEN` `CONNECT_MUST_BIND` `PMTU_DO` `ALWAYS_DF` `IP_TTL` `DEFERRED_BIND` `V6ONLY` `NOMCAST.`
`rcvbuf=129024`	Socket receive buffer size.
`sndbuf=129024`	Socket send buffer size.
`bindtodev=-1(01,0:0)`	Device to which the socket is bound, given as an interface, or -1 if unbound. This is followed by an (interface index, hardware port:vlan) tuple.
`ttl=64`	Initial TTL value.
`rcvtimeo_ms=0`	Timeout value (microseconds) before an error is generated for receive functions, as set by SO_RCVTIMEO.
`sndtimeo_ms=0`	Timeout value (microseconds) before an error is generated for send functions, as set by SO_SNDTIMEO.
`sigown=0`	The PID receiving signals from this socket.
`cmsg=`	Current message flags, including: `NO_MCAST_TX`.
`rx_errno=0`	Zero whilst data can still arrive, otherwise contains error code.
`tx_errno=0`	Zero if transmit can still happen, otherwise contains error code.
`so_error=0`	Current socket error, or zero if no error.
`os_sock=0`	0 if the socket is handled by Onload, 1 if the socket is handled by the OS and not by Onload.
`TX`	Socket is being used for transmit.
`epoll3: ready_list_id 0`	List of ready sockets from the epoll3 set.
`udpflags: FILT MCAST_LOOP RXOS`	UDP flags currently set for this socket, including: `FILT` `MCAST_LOOP` `IMP_BIND` `EFSND` `LAST_RCV_ON` `BIND` `MC_B2D` `NO_MC_B2D` `PEEKOS` `SO_TS` `MC` `MC_FILT` `NO_UC_FILT`.
`rcv:`	Receive data:
`q_pkts=0`	Number of packets currently in receive queue.
`reap=2`	Number of packet buffers in the process of being freed for reuse.
`tot_pkts=944560`	Total number of packet buffers used. Note any packets that are delivered to multiple receive queues get wrapped in an additional 0-length buffer, to reference those queues.
`rcv:`	Further receive data:
`oflow_drop=0(0%)`	Number of packets dropped because the buffer is full.
`mem_drop=0`	Number of packets dropped due to running out of packet buffer memory.
`eagain=0`	Number of times the application tried to read from a socket when there is no data ready. This value can be ignored on the receive side.
`pktinfo=0`	Number of times an `IP_PKTINFO` control message was received.
`q_max_pkts=0`	Maximum depth reached by the receive queue (packets).
`rcv:`	Further receive data:
`os=0(0%)`	Number of packets received via the operating system, both as a number and as a percentage of total packets received.
`os_slow=0`	Number of packets received via the operating system slow path.
`os_error=0`	Number of times a `recv()` function call via the operating system returned an error.
`snd:`	Send data:
`q=0+0`	Number of bytes sent to the interface but not yet transmitted, + number of bytes waiting because the interface lock is contended in `sendmsg()`.
`ul=944561`	Number of packets sent via Onload.
`os=0(0%)`	Number of packets sent via the operating system, both as a number and as a percentage of total packets sent.
`snd:`	Send data…
`LOCK`	…about locks:
`cp=1(0%)`	Count of locks held while updating the control plane.
`pkt=737815(99%)`	Count of locks to get a packet buffer.
`snd=3(0%)`	Count of locks held when sending.
`poll=0(0%)`	Count of locks held to poll the stack.
`defer=1(0%)`	Count of sends deferred to the lock holder.
`snd:`	Send data…
`MCAST`	…about multicast:
`if=9`	The interfaces being used by the UDP stack.
`src=172.16.128.28`	Source IP address for multicast.
`ttl=1`	Initial TTL value.
`snd:`	Send data…
`TO`	…about unconnected sends:
`n=737820`	Total number of UDP packets sent on this socket via Onload.
`match=737819(99%)`	Number of packets that matched the cache, both as a number and as a percentage of total packets sent.
`lookup=1+0(0%)`	Number of packets needing lookup, from the control plane + because unlocked, both as numbers and as a percentage of total packets sent.
`Onloaded(Valid)`	Status of cached control plane information, one of: `Onloaded` = can reach the destination via an accelerated interface `NoMac` `NoRoute` `ViaOs` `Local` `MacFail` followed by its validity: `(Valid)`: information is up-to-date. Can send immediately using this information. `(Old)`: information might be out-of-date. On next send Onload will do a control plane lookup - this will add some latency.
`snd:`	Further send data…
`TO`	…about unconnected sends:
`if=9`	Interface being used.
`mtu=1500`	MTU being used.
`intf_i=0`	Intf_i value.
`vlan=0`	VLAN being used.
`encap=4`	Types of encapsulation supported by the NIC, as a hexadecimal mask.
`snd:`	Further send data…
`TO`	…about unconnected sends:
`172.16.128.28:34645 =>`	UDP send multicast source ip:port address.
`224.1.2.3:8001`	UDP send multicast ip:port address.
`snd:`	Further send data…
`CON`	…about connected sends:
`n=0`	Total number of UDP packets sent on this socket via Onload.
`lookup=0`	Number of packets needing lookup from the control plane.
`NoRoute(Old)`	Status of cached control plane information, one of: `Onloaded` = can reach the destination via an accelerated interface `NoMac` `NoRoute` `ViaOs` `Local` `MacFail` followed by its validity: `(Valid)`: information is up-to-date. Can send immediately using this information. `(Old)`: information might be out-of-date. On next send Onload will do a control plane lookup - this will add some latency.
`snd:`	Further send data…
`CON`	…about connected sends:
`if=9`	Interface being used.
`mtu=0`	MTU being used.
`intf_i=-1`	Intf_i value.
`vlan=0`	VLAN being used.
`encap=0`	Types of encapsulation supported by the NIC, as a hexadecimal mask.
`snd:`	Further send data:
`eagain=0`	Count of the number of times the application tried to send data, but the transmit queue is already full. A high value on the send side might indicate transmit issues.
`spin=0`	Number of times process had to spin when the send queue was full.
`block=0`	Number of times process had to block when the send queue was full.
`snd:`	Further send data:
`poll_avoids_full=0`	Number of times polling created space in the send queue.
`fragments=0`	Number of (non first) fragments sent.
`confirm=0`	Number of packets sent with `MSG_CONFIRM` flag.
`snd:`	Further send data:
`os_slow=1`	Number of packets sent via the operating system slow path.
`os_late=0`	Number of packets sent via the operating system after copying
`unconnect_late=0`	Number of packets silently dropped when process/thread becomes disconnected during a send procedure.
`nomac=0(0%)`	Number of times when no MAC address was known, so ARP was required before delivering traffic.