from small one page howto to huge articles all in one place
 

search text in:





Poll
Which kernel version do you use?





poll results

Last additions:
using iotop to find disk usage hogs

using iotop to find disk usage hogs

words:

887

views:

103540

userrating:

average rating: 1.7 (85 votes) (1=very good 6=terrible)


May 25th. 2007:
Words

486

Views

218202

why adblockers are bad


Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

words:

161

views:

98816

userrating:

average rating: 1.3 (28 votes) (1=very good 6=terrible)


April, 26th. 2006:

Druckversion
You are here: manpages





MQPRIO

Section: Linux (8)
Updated: 24 Sept 2013
Index Return to Main Contents
 

NAME

MQPRIO - Multiqueue Priority Qdisc (Offloaded Hardware QOS)  

SYNOPSIS

tc qdisc ... dev dev ( parent classid | root) [ handle major: ] mqprio [ numtc tcs ] [ map P0 P1 P2... ] [ queues count1@offset1 count2@offset2 ... ] [ hw 1|0 ]

 

DESCRIPTION

The MQPRIO qdisc is a simple queuing discipline that allows mapping traffic flows to hardware queue ranges using priorities and a configurable priority to traffic class mapping. A traffic class in this context is a set of contiguous qdisc classes which map 1:1 to a set of hardware exposed queues.

By default the qdisc allocates a pfifo qdisc (packet limited first in, first out queue) per TX queue exposed by the lower layer device. Other queuing disciplines may be added subsequently. Packets are enqueued using the map parameter and hashed across the indicated queues in the offset and count. By default these parameters are configured by the hardware driver to match the hardware QOS structures.

Enabled hardware can provide hardware QOS with the ability to steer traffic flows to designated traffic classes provided by this qdisc. Configuring the hardware based QOS mechanism is outside the scope of this qdisc. Tools such as lldpad and ethtool exist to provide this functionality. Also further qdiscs may be added to the classes of MQPRIO to create more complex configurations.

 

ALGORITHM

On creation with 'tc qdisc add', eight traffic classes are created mapping priorities 0..7 to traffic classes 0..7 and priorities greater than 7 to traffic class 0. This requires base driver support and the creation will fail on devices that do not support hardware QOS schemes.

These defaults can be overridden using the qdisc parameters. Providing the 'hw 0' flag allows software to run without hardware coordination.

If hardware coordination is being used and arguments are provided that the hardware can not support then an error is returned. For many users hardware defaults should work reasonably well.

As one specific example numerous Ethernet cards support the 802.1Q link strict priority transmission selection algorithm (TSA). MQPRIO enabled hardware in conjunction with the classification methods below can provide hardware offloaded support for this TSA.

 

CLASSIFICATION

Multiple methods are available to set the SKB priority which MQPRIO uses to select which traffic class to enqueue the packet.
From user space
A process with sufficient privileges can encode the destination class directly with SO_PRIORITY, see socket(7).
with iptables/nftables
An iptables/nftables rule can be created to match traffic flows and set the priority. iptables(8)
with net_prio cgroups
The net_prio cgroup can be used to set the priority of all sockets belong to an application. See kernel and cgroup documentation for details.

 

QDISC PARAMETERS

num_tc
Number of traffic classes to use upto 16 classes supported.

map
The priority to traffic class map. Maps priorities 0..15 to a specified traffic class.

queues
Provide count and offset of queue range for each traffic class. In the format, count@offset. Queue ranges for each traffic classes cannot overlap and must be a contiguous range of queues.

hw
Set to 1 to use hardware QOS defaults. Set to 0 to override hardware defaults with user specified values.

 

AUTHORS

John Fastabend, <john.r.fastabend@intel.com>


 

Index

NAME
SYNOPSIS
DESCRIPTION
ALGORITHM
CLASSIFICATION
QDISC PARAMETERS
AUTHORS


Please read "Why adblockers are bad".



Other free services
toURL.org
Shorten long
URLs to short
links like
http://tourl.org/2
tourl.org
.
Reverse DNS lookup
Find out which hostname(s)
resolve to a
given IP or other hostnames for the server
www.reversednslookup.org
rdf newsfeed | rss newsfeed | Atom newsfeed
- Powered by LeopardCMS - Running on Gentoo -
Copyright 2004-2017 Sascha Nitsch Unternehmensberatung UG(haftungsbeschränkt)
Valid XHTML1.1 : Valid CSS : buttonmaker
- Level Triple-A Conformance to Web Content Accessibility Guidelines 1.0 -
- Copyright and legal notices -
Time to create this page: 3.5 ms