LinuxQuestions.org
Share your knowledge at the LQ Wiki.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Distributions > Slackware
User Name
Password
Slackware This Forum is for the discussion of Slackware Linux.

Notices


Reply
  Search this Thread
Old 08-22-2019, 06:52 PM   #1
ordealbyfire83
Member
 
Registered: Oct 2006
Location: Leiden, Netherlands
Distribution: LFS, Ubuntu Hardy
Posts: 269

Rep: Reputation: 48
Kernel Patches for Live DVD?


First please let me confess that I do not currently run Slackware on my main machine, but I do use two Slackware Live DVD's from time to time for testing and other purposes.

Currently I am trying to build a kernel for my BLFS system using the kernel version and config file found on Alien Bob's 20180909 version. I would like to know whether the 4.14.68 kernel on this DVD has been patched as I'm noticing a couple of differences in behavior between how this kernel acts from the DVD and how it does when I build the source myself.

For example, the Slackware kernel seems to obey "elevator=" but when built from source and unmodified config file it does not. etc.

Any thoughts?
 
Old 08-22-2019, 08:49 PM   #2
upnort
Senior Member
 
Registered: Oct 2014
Distribution: Slackware, Proxmox, Debian, CentOS, Ubuntu MATE
Posts: 1,198

Rep: Reputation: Disabled
I'm no kernel guru but the stock Slackware Current kernel config shows the following:

CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
CONFIG_IOSCHED_BFQ=m

Perhaps compare the kernel configs.
 
Old 08-23-2019, 07:55 AM   #3
Alien Bob
Slackware Contributor
 
Registered: Sep 2005
Location: Eindhoven, The Netherlands
Distribution: Slackware
Posts: 7,681

Rep: Reputation: 6187Reputation: 6187Reputation: 6187Reputation: 6187Reputation: 6187Reputation: 6187Reputation: 6187Reputation: 6187Reputation: 6187Reputation: 6187Reputation: 6187
Quote:
Originally Posted by ordealbyfire83 View Post
... using the kernel version and config file found on Alien Bob's 20180909 version. I would like to know whether the 4.14.68 kernel on this DVD has been patched...
The Slackware Live ISOs all use stock Slackware kernels. No Slackware package gets (re-)built when generating such an ISO image. It's all integrated using a ready Slackware package tree downloaded from an Internet mirror.
 
3 members found this post helpful.
Old 08-23-2019, 03:09 PM   #4
ordealbyfire83
Member
 
Registered: Oct 2006
Location: Leiden, Netherlands
Distribution: LFS, Ubuntu Hardy
Posts: 269

Original Poster
Rep: Reputation: 48
Thank you both for that information. I'd much rather not be poking around with these I/O schedulers - but if there are no patches then something in the kernel isn't acting as it should.

After reading this it looks like newer kernels first check if a device (or a device plus whatever motherboard circuitry?) supports multi-queue. Unless multi-queue is specifically enabled, then it falls back to NOOP and ignores whatever elevator= specified. So even setting a default scheduler in the config isn't likely to work nowadays. This is unreasonable, because if we do not use multi-queue then we should be able to specify another scheduler. (Reverting this patch didn't help either.)

In my situation I am booting from a LUKS partition on a SSD. Using NOOP causes hangs after doing anything I/O intensive. Deadline gives me the best results, but then again, I can only hibernate / resume daily for 2-3 weeks before it hangs. I preferred elevator=deadline because this gives all devices the same scheduler. Copying large files from one device on NOOP to another on deadline or cfq never seems to end well, and I've even had files utterly vanish.

My conclusion about the Slackware kernel may have been premature. If I unpack the initrd, add a line to print out the scheduler, I do indeed see deadline, but then when I query this from the OS after it is booted, I get NOOP.
 
Old 09-04-2019, 11:52 PM   #5
bassmadrigal
LQ Guru
 
Registered: Nov 2003
Location: West Jordan, UT, USA
Distribution: Slackware
Posts: 6,184

Rep: Reputation: 3923Reputation: 3923Reputation: 3923Reputation: 3923Reputation: 3923Reputation: 3923Reputation: 3923Reputation: 3923Reputation: 3923Reputation: 3923Reputation: 3923
From some previous testing on a thread in this forum, it was determined that any elevator set in the kernel could be overridden with settings in udev. In fact, eudev does have a rule that will set any non-rotational devices (SSDs, NVMe, and maybe USB thumbdrives) to the noop elevator. This eudev rule will override any kernel or bootloader settings for default elevators for non-rotational devices.

If you want it set to your own elevator, you can do it by creating a rule to override the default eudev rule. In my example below, I named it 55-ssd-schedular.rules, and it is placed in /etc/udev/rules.d/ and sets the default schedular for any /dev/sd* devices that don't rotate to deadline.

Code:
jbhansen@craven-moorhead:~$ cat /etc/udev/rules.d/55-ssd-schedular.rules
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="deadline"
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
Slackware 14.2 "Slacker" live DVD/USB featuring XFCE4, Kernel 4.19.29-xanmod15, and Linux-Live Kit linus72 Slackware 119 07-19-2019 06:47 AM
List Installed Patches by Live Update? ubyt3m3 Solaris / OpenSolaris 4 07-07-2008 01:18 PM
patches for a release version or slackware/slackware-ver.#/patches acummings Slackware 2 07-05-2007 01:05 AM
RedHat patches vs open source patches paulsh2k4 Linux - Software 1 10-14-2004 03:18 AM
DVD-R, DVD+RW, DVD-RW and DVD+R zetsui Linux - Hardware 5 09-12-2003 06:15 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Distributions > Slackware

All times are GMT -5. The time now is 07:40 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration