пакетная ограниченная очередь первым пришел - первым вышел (Packet limited First In, First Out queue)
Имя (Name)
pfifo - Packet limited First In, First Out queue
bfifo - Byte limited First In, First Out queue
Синопсис (Synopsis)
tc qdisc ... add pfifo [ limit packets ]
tc qdisc ... add bfifo [ limit bytes ]
Описание (Description)
The pfifo and bfifo qdiscs are unadorned First In, First Out
queues. They are the simplest queues possible and therefore have
no overhead. pfifo constrains the queue size as measured in
packets. bfifo does so as measured in bytes.
Like all non-default qdiscs, they maintain statistics. This might
be a reason to prefer pfifo or bfifo over the default.
Алгоритм (Algorithm)
A list of packets is maintained, when a packet is enqueued it
gets inserted at the tail of a list. When a packet needs to be
sent out to the network, it is taken from the head of the list.
If the list is too long, no further packets are allowed on. This
is called 'tail drop'.
Параметры (Parameters)
limit Maximum queue size. Specified in bytes for bfifo, in
packets for pfifo. For pfifo, defaults to the interface
txqueuelen, as specified with ifconfig(8) or ip(8). The
range for this parameter is [0, UINT32_MAX].
For bfifo, it defaults to the txqueuelen multiplied by the
interface MTU. The range for this parameter is [0,
UINT32_MAX] bytes.
Note: The link layer header was considered when counting
packets length.
Вывод (Output)
The output of tc -s qdisc ls contains the limit, either in
packets or in bytes, and the number of bytes and packets actually
sent. An unsent and dropped packet only appears between braces
and is not counted as 'Sent'.
In this example, the queue length is 100 packets, 45894 bytes
were sent over 681 packets. No packets were dropped, and as the
pfifo queue does not slow down packets, there were also no
overlimits:
# tc -s qdisc ls dev eth0
qdisc pfifo 8001: dev eth0 limit 100p
Sent 45894 bytes 681 pkts (dropped 0, overlimits 0)
If a backlog occurs, this is displayed as well.
Смотри также (See also)
tc(8)
