Changing qdisc algorithm sysctl and tc
What qdisc is controlled via the tc command versus sysctl net.core.default_qdisc? Consider
$ tc qdisc show dev eth2
qdisc mq 0: dev eth2 root
$ sysctl net.core.default_qdisc
net.core.default_qdisc = pfifo_fast
On this system, the default qdisc is set to pfifo_fast but the qdisc in use is mq (Multi-queue) after a reboot. It's rather obvious that they are not directly related, or at the least, not in a manner which makes sense "out of the box". This link about queuing in the Linux Network Stack makes it clear that tc qdisc ... applies to the Queue which sits between the IP Stack and the Driver Queue.
Can anyone disambiguate these two for me?
networking kernel network-interface
edited Nov 12 '18 at 22:06
Rui F Ribeiro
39.9k1479135
asked Nov 12 '18 at 22:05
Andrew FalangaAndrew Falanga
249312
add a comment |
What qdisc is controlled via the tc command versus sysctl net.core.default_qdisc? Consider
$ tc qdisc show dev eth2
qdisc mq 0: dev eth2 root
$ sysctl net.core.default_qdisc
net.core.default_qdisc = pfifo_fast
On this system, the default qdisc is set to pfifo_fast but the qdisc in use is mq (Multi-queue) after a reboot. It's rather obvious that they are not directly related, or at the least, not in a manner which makes sense "out of the box". This link about queuing in the Linux Network Stack makes it clear that tc qdisc ... applies to the Queue which sits between the IP Stack and the Driver Queue.
Can anyone disambiguate these two for me?
networking kernel network-interface
edited Nov 12 '18 at 22:06
Rui F Ribeiro
39.9k1479135
asked Nov 12 '18 at 22:05
Andrew FalangaAndrew Falanga
249312
add a comment |
What qdisc is controlled via the tc command versus sysctl net.core.default_qdisc? Consider
$ tc qdisc show dev eth2
qdisc mq 0: dev eth2 root
$ sysctl net.core.default_qdisc
net.core.default_qdisc = pfifo_fast
On this system, the default qdisc is set to pfifo_fast but the qdisc in use is mq (Multi-queue) after a reboot. It's rather obvious that they are not directly related, or at the least, not in a manner which makes sense "out of the box". This link about queuing in the Linux Network Stack makes it clear that tc qdisc ... applies to the Queue which sits between the IP Stack and the Driver Queue.
Can anyone disambiguate these two for me?
networking kernel network-interface
edited Nov 12 '18 at 22:06
Rui F Ribeiro
39.9k1479135
asked Nov 12 '18 at 22:05
Andrew FalangaAndrew Falanga
249312
What qdisc is controlled via the tc command versus sysctl net.core.default_qdisc? Consider
$ tc qdisc show dev eth2
qdisc mq 0: dev eth2 root
$ sysctl net.core.default_qdisc
net.core.default_qdisc = pfifo_fast
On this system, the default qdisc is set to pfifo_fast but the qdisc in use is mq (Multi-queue) after a reboot. It's rather obvious that they are not directly related, or at the least, not in a manner which makes sense "out of the box". This link about queuing in the Linux Network Stack makes it clear that tc qdisc ... applies to the Queue which sits between the IP Stack and the Driver Queue.
Can anyone disambiguate these two for me?
networking kernel network-interface
networking kernel network-interface
edited Nov 12 '18 at 22:06
Rui F Ribeiro
39.9k1479135
asked Nov 12 '18 at 22:05
Andrew FalangaAndrew Falanga
249312
edited Nov 12 '18 at 22:06
Rui F Ribeiro
39.9k1479135
asked Nov 12 '18 at 22:05
Andrew FalangaAndrew Falanga
249312
edited Nov 12 '18 at 22:06
Rui F Ribeiro
39.9k1479135
edited Nov 12 '18 at 22:06
Rui F Ribeiro
39.9k1479135
edited Nov 12 '18 at 22:06
Rui F Ribeiro
39.9k1479135
39.9k1479135
asked Nov 12 '18 at 22:05
Andrew FalangaAndrew Falanga
249312
asked Nov 12 '18 at 22:05
Andrew FalangaAndrew Falanga
249312
asked Nov 12 '18 at 22:05
Andrew FalangaAndrew Falanga
249312
249312
add a comment |
add a comment |
1 Answer
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The multiqueue ("mq") scheduler enables the Linux kernel to support a feature called Receive-Side-Scaling (RSS) where the load for packet processing is distributed across multiple CPU cores.
On my Ubuntu 18.04.1 Desktop system with net.core.default_qdisc set to pfifo_fast and I execute the following command:
$ tc qdisc show dev eth0
This is what is output:
qdisc mq 0: root
qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
The mq scheduler has configured two pfifo_fast queues on device eth0 by default.
Hope this clears things up.
answered Jan 28 at 1:50
E. SmithE. Smith
1
add a comment |
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1 Answer
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1 Answer
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active
oldest
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active
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active
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votes
The multiqueue ("mq") scheduler enables the Linux kernel to support a feature called Receive-Side-Scaling (RSS) where the load for packet processing is distributed across multiple CPU cores.
On my Ubuntu 18.04.1 Desktop system with net.core.default_qdisc set to pfifo_fast and I execute the following command:
$ tc qdisc show dev eth0
This is what is output:
qdisc mq 0: root
qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
The mq scheduler has configured two pfifo_fast queues on device eth0 by default.
Hope this clears things up.
answered Jan 28 at 1:50
E. SmithE. Smith
1
add a comment |
The multiqueue ("mq") scheduler enables the Linux kernel to support a feature called Receive-Side-Scaling (RSS) where the load for packet processing is distributed across multiple CPU cores.
On my Ubuntu 18.04.1 Desktop system with net.core.default_qdisc set to pfifo_fast and I execute the following command:
$ tc qdisc show dev eth0
This is what is output:
qdisc mq 0: root
qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
The mq scheduler has configured two pfifo_fast queues on device eth0 by default.
Hope this clears things up.
answered Jan 28 at 1:50
E. SmithE. Smith
1
add a comment |
The multiqueue ("mq") scheduler enables the Linux kernel to support a feature called Receive-Side-Scaling (RSS) where the load for packet processing is distributed across multiple CPU cores.
On my Ubuntu 18.04.1 Desktop system with net.core.default_qdisc set to pfifo_fast and I execute the following command:
$ tc qdisc show dev eth0
This is what is output:
qdisc mq 0: root
qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
The mq scheduler has configured two pfifo_fast queues on device eth0 by default.
Hope this clears things up.
answered Jan 28 at 1:50
E. SmithE. Smith
1
The multiqueue ("mq") scheduler enables the Linux kernel to support a feature called Receive-Side-Scaling (RSS) where the load for packet processing is distributed across multiple CPU cores.
On my Ubuntu 18.04.1 Desktop system with net.core.default_qdisc set to pfifo_fast and I execute the following command:
$ tc qdisc show dev eth0
This is what is output:
qdisc mq 0: root
qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
The mq scheduler has configured two pfifo_fast queues on device eth0 by default.
Hope this clears things up.
answered Jan 28 at 1:50
E. SmithE. Smith
1
answered Jan 28 at 1:50
E. SmithE. Smith
1
answered Jan 28 at 1:50
E. SmithE. Smith
1
answered Jan 28 at 1:50
E. SmithE. Smith
1
1
add a comment |
add a comment |
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