Ryfujk

Java - What do constructor type arguments mean when placed *before* the type?

I2C signal and power over long range (10meter cable)

Giant Toughroad SLR 2 for 200 miles in two days, will it make it?

Teaching indefinite integrals that require special-casing

Have I saved too much for retirement so far?

Why are all the doors on Ferenginar (the Ferengi home world) far shorter than the average Ferengi?

The One-Electron Universe postulate is true - what simple change can I make to change the whole universe?

How do I repair my stair bannister?

Could solar power be utilized and substitute coal in the 19th century?

Books on the History of math research at European universities

Are Warlocks Arcane or Divine?

Resetting two CD4017 counters simultaneously, only one resets

Can the harmonic series explain the origin of the major scale?

Are taller landing gear bad for aircraft, particulary large airliners?

Greatest common substring

What will be the benefits of Brexit?

Freedom of speech and where it applies

Is there a problem with hiding "forgot password" until it's needed?

Can the electrostatic force be infinite in magnitude?

"lassen" in meaning "sich fassen"

How do ultrasonic sensors differentiate between transmitted and received signals?

What to do when my ideas aren't chosen, when I strongly disagree with the chosen solution?

Reply ‘no position’ while the job posting is still there (‘HiWi’ position in Germany)

Is there enough fresh water in the world to eradicate the drinking water crisis?

irqbalance on linux and dropped packets

how to use several computers as a cluster?Monitor dual intel xeon cpu load?Dropped connections between Linux Servers in Data CenterIPSec software that can use multiple CPU coresOptimizing Linux Compute ClusterHas anyone seen this kernel panic? What to do? (Ubuntu 10.04 LTS)Mysteriously dropped packetsinterrupt coalescing for high bandwidth packet capture?ifconfig eth0 RX dropped packetsksoftirqd and events process high CPU load

0

1

I am investigating dropped packets on a dual core, quad XEON box running Linux. One thing I see is irqbalance running on the system. I have a couple of questions. Reading the docs here I think I understand how it is supposed to work, but one thing that seems confusing is this line - "The current Linux irqbalance program is several years old in design, and is blissfully unaware of the ideas of Quad (or even Dual) core or even power usage. The program is conceptually closer to the naive balancing than to the smart interrupt balancer." This seems to indicate that there is an old and a new version of irqbalance. Is this the case? How can you tell which is running on the machine.

Also, if my goal is to optimize packet processing during bursts, do I want to run irqbalance, or should I manually bind the network card to a set of CPUs?

linux packets

share|improve this question

edited Oct 21 '15 at 15:49

HBruijn

55.6k1190149

asked Jul 25 '12 at 4:49

Andy FAndy F

1213

bumped to the homepage by Community♦ 10 mins ago

This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.

add a comment | 

0

1

I am investigating dropped packets on a dual core, quad XEON box running Linux. One thing I see is irqbalance running on the system. I have a couple of questions. Reading the docs here I think I understand how it is supposed to work, but one thing that seems confusing is this line - "The current Linux irqbalance program is several years old in design, and is blissfully unaware of the ideas of Quad (or even Dual) core or even power usage. The program is conceptually closer to the naive balancing than to the smart interrupt balancer." This seems to indicate that there is an old and a new version of irqbalance. Is this the case? How can you tell which is running on the machine.

Also, if my goal is to optimize packet processing during bursts, do I want to run irqbalance, or should I manually bind the network card to a set of CPUs?

linux packets

share|improve this question

edited Oct 21 '15 at 15:49

HBruijn

55.6k1190149

asked Jul 25 '12 at 4:49

Andy FAndy F

1213

bumped to the homepage by Community♦ 10 mins ago

This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.

add a comment | 

I am investigating dropped packets on a dual core, quad XEON box running Linux. One thing I see is irqbalance running on the system. I have a couple of questions. Reading the docs here I think I understand how it is supposed to work, but one thing that seems confusing is this line - "The current Linux irqbalance program is several years old in design, and is blissfully unaware of the ideas of Quad (or even Dual) core or even power usage. The program is conceptually closer to the naive balancing than to the smart interrupt balancer." This seems to indicate that there is an old and a new version of irqbalance. Is this the case? How can you tell which is running on the machine.

Also, if my goal is to optimize packet processing during bursts, do I want to run irqbalance, or should I manually bind the network card to a set of CPUs?

linux packets

share|improve this question

edited Oct 21 '15 at 15:49

HBruijn

55.6k1190149

asked Jul 25 '12 at 4:49

Andy FAndy F

1213

share|improve this question

edited Oct 21 '15 at 15:49

HBruijn

55.6k1190149

asked Jul 25 '12 at 4:49

Andy FAndy F

1213

share|improve this question

edited Oct 21 '15 at 15:49

HBruijn

55.6k1190149

asked Jul 25 '12 at 4:49

Andy FAndy F

1213

edited Oct 21 '15 at 15:49

HBruijn

55.6k1190149

edited Oct 21 '15 at 15:49

HBruijn

55.6k1190149

asked Jul 25 '12 at 4:49

Andy FAndy F

1213

asked Jul 25 '12 at 4:49

Andy FAndy F

1213

2 Answers
2

active

oldest

votes

0

By "current", it means what was common when that page was written, five years ago or so. Every modern Linux distribution that you are likely to use has a modern, smart irqbalance. You're trying to fix a problem that is very, very unlikely to exist.

share|improve this answer

answered Jul 25 '12 at 7:33

David SchwartzDavid Schwartz

28.6k14372

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  David, thanks for your answer about the version of irqbalance. I neglected to mention that this system is used in high frequency trading. In this domain, I know that quite a few systems tweak their IRQs and CPU affinities, so while you're right that this is a very unusual aspect to look at for general networking, I need to make sure I understand how this part of the system works.
  
  – Andy F
  Jul 25 '12 at 12:15
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try irqbalance --debug --oneshot to see what irqbalance is doing.
  
  – David Schwartz
  Jul 25 '12 at 12:17
  

  
  
  
  

add a comment | 

0

One solution to this problem is to use a combination of disabling irqbalance, cpu isolation and pinning the NIC interrupts to an isolated CPU.

• Disable irqbalance. This will cause all interrupts to be on CPU0


• Isolate CPUs 1-3 via a kernel boot parameter "isolcpus=1-3"


• Manually pin the interrupts for the NIC to one of the isolated CPUs (echo 'cpumask' . /proc/irq//smp_affinity).

Doing this will allow the NIC to have its IRQs run on a CPU which is not bothered by random kernel threads and IRQs from other hardware devices.

Here's a good explanation of how to pin an IRQ to a specific CPU.

https://cs.uwaterloo.ca/~brecht/servers/apic/SMP-affinity.txt

share|improve this answer

answered Jan 17 '17 at 1:47

bgoldbergbgoldberg

262

add a comment | 

Your Answer

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "2"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fserverfault.com%2fquestions%2f410928%2firqbalance-on-linux-and-dropped-packets%23new-answer', 'question_page');
}
);

Post as a guest

Name

Email

Required, but never shown

0

By "current", it means what was common when that page was written, five years ago or so. Every modern Linux distribution that you are likely to use has a modern, smart irqbalance. You're trying to fix a problem that is very, very unlikely to exist.

share|improve this answer

answered Jul 25 '12 at 7:33

David SchwartzDavid Schwartz

28.6k14372

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  David, thanks for your answer about the version of irqbalance. I neglected to mention that this system is used in high frequency trading. In this domain, I know that quite a few systems tweak their IRQs and CPU affinities, so while you're right that this is a very unusual aspect to look at for general networking, I need to make sure I understand how this part of the system works.
  
  – Andy F
  Jul 25 '12 at 12:15
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try irqbalance --debug --oneshot to see what irqbalance is doing.
  
  – David Schwartz
  Jul 25 '12 at 12:17
  

  
  
  
  

add a comment | 

0

By "current", it means what was common when that page was written, five years ago or so. Every modern Linux distribution that you are likely to use has a modern, smart irqbalance. You're trying to fix a problem that is very, very unlikely to exist.

share|improve this answer

answered Jul 25 '12 at 7:33

David SchwartzDavid Schwartz

28.6k14372

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  David, thanks for your answer about the version of irqbalance. I neglected to mention that this system is used in high frequency trading. In this domain, I know that quite a few systems tweak their IRQs and CPU affinities, so while you're right that this is a very unusual aspect to look at for general networking, I need to make sure I understand how this part of the system works.
  
  – Andy F
  Jul 25 '12 at 12:15
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try irqbalance --debug --oneshot to see what irqbalance is doing.
  
  – David Schwartz
  Jul 25 '12 at 12:17
  

  
  
  
  

add a comment | 

By "current", it means what was common when that page was written, five years ago or so. Every modern Linux distribution that you are likely to use has a modern, smart irqbalance. You're trying to fix a problem that is very, very unlikely to exist.

share|improve this answer

answered Jul 25 '12 at 7:33

David SchwartzDavid Schwartz

28.6k14372

share|improve this answer

answered Jul 25 '12 at 7:33

David SchwartzDavid Schwartz

28.6k14372

answered Jul 25 '12 at 7:33

David SchwartzDavid Schwartz

28.6k14372

answered Jul 25 '12 at 7:33

David SchwartzDavid Schwartz

28.6k14372

0

One solution to this problem is to use a combination of disabling irqbalance, cpu isolation and pinning the NIC interrupts to an isolated CPU.

• Disable irqbalance. This will cause all interrupts to be on CPU0


• Isolate CPUs 1-3 via a kernel boot parameter "isolcpus=1-3"


• Manually pin the interrupts for the NIC to one of the isolated CPUs (echo 'cpumask' . /proc/irq//smp_affinity).

Doing this will allow the NIC to have its IRQs run on a CPU which is not bothered by random kernel threads and IRQs from other hardware devices.

Here's a good explanation of how to pin an IRQ to a specific CPU.

https://cs.uwaterloo.ca/~brecht/servers/apic/SMP-affinity.txt

share|improve this answer

answered Jan 17 '17 at 1:47

bgoldbergbgoldberg

262

add a comment | 

0

One solution to this problem is to use a combination of disabling irqbalance, cpu isolation and pinning the NIC interrupts to an isolated CPU.

• Disable irqbalance. This will cause all interrupts to be on CPU0


• Isolate CPUs 1-3 via a kernel boot parameter "isolcpus=1-3"


• Manually pin the interrupts for the NIC to one of the isolated CPUs (echo 'cpumask' . /proc/irq//smp_affinity).

Doing this will allow the NIC to have its IRQs run on a CPU which is not bothered by random kernel threads and IRQs from other hardware devices.

Here's a good explanation of how to pin an IRQ to a specific CPU.

https://cs.uwaterloo.ca/~brecht/servers/apic/SMP-affinity.txt

share|improve this answer

answered Jan 17 '17 at 1:47

bgoldbergbgoldberg

262

add a comment | 

One solution to this problem is to use a combination of disabling irqbalance, cpu isolation and pinning the NIC interrupts to an isolated CPU.

• Disable irqbalance. This will cause all interrupts to be on CPU0


• Isolate CPUs 1-3 via a kernel boot parameter "isolcpus=1-3"


• Manually pin the interrupts for the NIC to one of the isolated CPUs (echo 'cpumask' . /proc/irq//smp_affinity).

Doing this will allow the NIC to have its IRQs run on a CPU which is not bothered by random kernel threads and IRQs from other hardware devices.

Here's a good explanation of how to pin an IRQ to a specific CPU.

https://cs.uwaterloo.ca/~brecht/servers/apic/SMP-affinity.txt

share|improve this answer

answered Jan 17 '17 at 1:47

bgoldbergbgoldberg

262

share|improve this answer

answered Jan 17 '17 at 1:47

bgoldbergbgoldberg

262

answered Jan 17 '17 at 1:47

bgoldbergbgoldberg

262

answered Jan 17 '17 at 1:47

bgoldbergbgoldberg

262