What is low latency kernel?  When do we need to use it? Any something may be affected when we use low latency kernel?
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After installing Ubuntu Studio 12.04, I have found that it uses a low latency kernel.   I searched for an explanation and how to change back it to a real-time or generic one. However, it looks like this part of Linux hasn't been covered to explain the details.   Q: Why choose a low latency kernel over a generic or real-time one?  PS: I have already read the answers from  question and  post.
29746
Per the kernel documentation:  This control is used to define how aggressive the kernel will swap memory pages.  Higher values will increase aggressiveness, lower values decrease the amount of swap.   However this is kind of vague. I'm trying to figure out exactly what the parameter ultimately controls. I know it adjusts how aggressively the kernel tries to swap out pages, but what decision making process in the kernel code does it affect?  Does it adjust how long ago a page must have been accessed before the kernel swaps it out? If so what does the default value of 60 represent? And how much is changed by a increment/decrement of 1 (a formula would be nice)? Or does it swap out pages based on their access frequency? Or something else?
111269
My machine was updated today to Ubuntu 16.04.2. However, the kernel is still "4.4.0-62-generic". What happened (it seemed that the principal advantage of the 16.04.2 version was the update of the kernel to 4.8) ? Do I have to make a fresh install ?
42636
Is there any tool that helps to determine the weakest link of my current laptop hardware specification? Any online guide to help me choose nice balanced configuration for the new laptop?    I need to find the answers:  a) which component should be invested to increase overall performance the most? CPU? GPU? RAM?  b) which component may decrease overall performance and work as a bottleneck for the specific configuration?    The question is general and regards both to validating the current hardware usage (and its possible bottlenecks) and estimating the performance (and avoiding possible issues) of specs I'm going to choose and buy.    P.S. For the specific laptop I need to replace, the following software will be in use:    Windows antivirus, firewall, dropbox service running in the background mail app + web browser with a dozen or so tabs open from time to time: libreoffice apps, movies, games (both online and installed).
106001
I have a MacBook Pro (5,1) with 4GB of memory running 10A432 - but it's running the 32-bit kernel.  Any ideas why it wouldn't be running in 64-bit mode, and how I can get it to do so?
11471
I'm trying to detect what filesystems a kernel can support. Ideally in a little list of their names but I'll take anything you've got.  Note that I don't mean , just ones that the current kernel could, theoretically support directly (obviously, fuse could support infinite numbers more).
104887
I have 3 old computers lying around right now running a P2 at 800 MHz(?), Intel Mobile 1.6 GHz, AMD Athlon XP 2000+ at 1.66 GHz, and (might not use this) P4 at 2.7 GHz, all with 512 MB Ram, and am considering clustering them together for fun/knowledge. They would be running an undecided version of linux, preferably ubuntu based.   The issue is what I want to use it for: general computing and occasional video encoding. By general computing I mean day to day tasks. However I'm not sure if every program started by a single X session is going to exist on the same machine, defeating the purpose of such a system. Will programs be split up or exist on one machine?  Second, assuming this is running 100baseT ethernet (not sure if the PCI slot itself could handle Gigabit), would the speed of having a program exist over the network be an issue? It seems that the constant asking of various things in RAM would be quite slow.  And before you say "buy another computer!", that's not the point of this question. I'm asking would it be usable, not necessarily practical. And yes I know, this is going to be extreamly power consuming.
4936
The latest kernel is causing problems with my sound, which worked fine with an older version. As I have only Ubuntu installed, Grub is not getting displayed while booting. How can I manually choose my kernel version while booting?
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After the most recent kernel upgrade, my system hangs during boot.  Since my machine seems especially persnickety about pulling up the grub menu*, what is the best way to set the previous kernel as the default until the next upgrade?  *I have to hit ESC at exactly the right moment, which usually means rebooting several times until I get it.
23013
When I log in with LightDM on my laptop running Debian Unstable, it recently started to hang for around 2 minutes until journalctl shows the message kernel: random: crng init done. When I press random keys on my keyboard while it hangs, it logs in faster (around 10 seconds). Before I didn't have this issue, is there any way I can fix it?  Edit: using linux-image-4.15.0-3-amd64 instead of linux-image-4.16.0-1-amd64 works, but I don't want to use an older kernel.
123628
I keep hearing that this is a huge no-no. Why is this? I run Ubuntu mostly so it doesn't affect me, but I was just wondering.
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Why, for example, would a 2.66 GHz dual-core Core i5 be faster than a 2.66 GHz Core 2 Duo, which is also dual-core?  Is this because of newer instructions that can process information in fewer clock cycles? What other architectural changes are involved?     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this question. Feel free to edit the answers to add additional details.
10997
I'm running a linux box(ubuntu) and every few months it freezes and I'm left with no choice(SysRq-F and other keyboard shortcuts are not working) but to reboot it losing all the data.   I'm wondering why the kernel is not killing the processe(s) that eats the memory or CPU?   What's the point keeping the system in a frozen/unresponsive state?
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What is the difference between a "Non-preemptive", "Preemptive" and "Selective Preemptive" Kernel?    Hope someone can shed some light into this.
63990
Dell LAtitude E6430 with CPU Intel® Core™ i5-3210M, 64 bits, no longer boots after updating 14.04 LTS system to kernel 3.13.0-66. It hangs off after completion of the password. Back to the 3.13.0-64 kernel works, but still with a system error, pending since about the beginning of the year (beginning approximately for the kernel 3.13.0-40) and never corrected by subsequent upgrades. It seems that the system 14.04 LTS is going worse and worse on this computer. Is there a solution ?
57674
I'm running Debian Stretch and Linux kernel version 4.9.110-3+deb9u4, with a modified config. I'm observing the following weird behaviour   Set the hardware clock to 2016-01-01 00:00:00 UTC Reboot dmesg reports reading the hardware clock similar to what was set previously date reports 2016-11-03 17:16:42 UTC   The above behaviour is observed with any date before 2016-11-03 17:00:00 UTC. I haven't narrowed down any further than that.  The kernel source code has not been changed, nor am I running any custom kernel modules. I have also observed this with using the 4.9.168 kernel from the Debian repos, as well as the 4.19.37 kernel from stretch-backports. I have also been able to reproduce this on a DigitalOcean droplet running Stretch and 4.9.168.  I have not seen this problem occur when I set a date after 2016-11-03. It doesn't seem likely, but it seems like the kernel is forcing some minimum date.  Does anybody have a clue on this?  Logs from my VM:  root@debian-vm:~# timedatectl        Local time: Thu 2016-11-03 17:17:02 UTC   Universal time: Thu 2016-11-03 17:17:02 UTC         RTC time: Fri 2016-01-01 00:29:00        Time zone: Etc/UTC (UTC, +0000)  Network time on: yes NTP synchronized: no  RTC in local TZ: no root@debian-vm:~# dmesg | grep rtc [    0.985653] rtc_cmos 00:01: registered as rtc0 [    0.985670] rtc_cmos 00:01: alarms up to one month, y3k, 114 bytes nvram, hpet irqs [    1.032409] rtc_cmos 00:01: setting system clock to 2016-01-01 00:28:37 UTC (1451608117)   Logs from a DigitalOcean droplet:  root@debian-s-1vcpu-1gb-sfo2-01:~# timedatectl                                                                                                                                                                                                                                                                                                             Local time: Thu 2016-11-03 17:17:05 UTC   Universal time: Thu 2016-11-03 17:17:05 UTC         RTC time: Fri 2016-01-01 00:00:46        Time zone: Etc/UTC (UTC, +0000)  Network time on: yes NTP synchronized: no  RTC in local TZ: no
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Is there a set of patches around for linux kernel that address accuracy of (system, rather than user) process time?  i've heard about RTLinux, but i don't really need the actual real-time scheduling constraints, i just need that the time measurements are accurate. If the process switch slipped by a couple milliseconds, so be it, but i need an accurate measurement of the actual time spent in the current process