The HTB implementation in libnl uses units of microseconds in a number
of places where it seems TC is expecting time in units of ticks, which
causes actual rates much higher than requested. Additionally, libnl
uses USER_HZ for calculating buffer and cbuffer sizes, which can
result in much larger buffers than necessary on systems with high
resolution timers.
Note that the TBF qdisc uses microseconds incorrectly in two spots as
well, I fixed this but did not test.
The plug qdisc supports two operations - plug and unplug. When the
qdisc receives a plug ("buffer") command via netlink request,
packets arriving henceforth are buffered until a corresponding unplug
command is received. Depending on the type of unplug ("release_one"
or "release_indefinite"), the queue can be unplugged indefinitely or
selectively.
The plug qdisc allows a user to implement network output buffering
(aka output commit), used commonly in checkpoint based fault tolerance
systems. It also supports a general purpose queue plug/unplug
functionality.
The associated kernel module is available in David Miller's net-next
tree, commit: c3059be16c9ef29c05f0876a9df5fea21f29724f
This patch introduces userspace tools and API, to control the qdisc
via netlink messages.
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Signed-off-by: Thomas Graf <tgraf@redhat.com>
