DaemonForums  

Go Back   DaemonForums > OpenBSD > OpenBSD General

OpenBSD General Other questions regarding OpenBSD which do not fit in any of the categories below.

Reply
 
Thread Tools Display Modes
  #1   (View Single Post)  
Old 9th June 2008
mish's Avatar
mish mish is offline
Port Guard
 
Join Date: May 2008
Location: Makati City, Philippines
Posts: 25
Thanked 0 Times in 0 Posts
Default Henning Brauer takes up the cudgels for kernel cUst0mIz0rz =)

From misc@, 060708:
Quote:
Date: Sat, 7 Jun 2008 19:39:42 +0200
From: Henning Brauer <lists-openbsd@bsws.de>
To: misc@openbsd.org
Subject: Re: "remove any unwanted devices from the kernel. "
Message-ID: <20080607173942.GB7628@nudo.bsws.de>

* Jon <jonforthewin@gmail.com> [2008-06-06 03:04]:
> Why would someone want to do this?

because it is plain boring to just use GENERIC.

fiddling with your kernel, you can waste a lot of time to get it to
compile, then brag about that over beer with your friends, and while
they keep drinking your pager alerts you back because your kernel
crashed, since you also like to play with compiler "optimization"
levels. While you are allowed to play more iwth your kernel, your
friends just sit somewhere and drink, what a choice.
After a while you don't have friends any more, but a custom kernel that
boots 3 seconds faster than GENERIC and is stable for some time.
Certainly worth it.

--
Henning Brauer, hb@bsws.de, henning@openbsd.org
BS Web Services, http://bsws.de
Full-Service ISP - Secure Hosting, Mail and DNS Services
Dedicated Servers, Rootservers, Application Hosting - Hamburg & Amsterdam
Reply With Quote
  #2   (View Single Post)  
Old 9th June 2008
BSDfan666 BSDfan666 is offline
Real Name: N/A, this is the interweb.
Helpful companion
 
Join Date: Apr 2008
Location: Ontario, Canada
Posts: 2,223
Thanked 193 Times in 184 Posts
Default

I'll never understand why people insist on tinkering with their kernel... it's like a person rewiring their new cars electrical system an hour after purchasing it.

If you want a slightly faster boot time, use instead config(8), Any performance gains from customizing GENERIC will be *very* negligible.

Also, don't mess with the CFLAGS, while it's common practise for Linux users to add "optimizations", they're unnecessary and often *dangerous* when messed with.
Reply With Quote
  #3   (View Single Post)  
Old 9th June 2008
unicyclist unicyclist is offline
Fdisk Soldier
 
Join Date: May 2008
Posts: 54
Thanked 2 Times in 2 Posts
Default

Quote:
Originally Posted by BSDfan666 View Post
I'll never understand why people insist on tinkering with their kernel... it's like a person rewiring their new cars electrical system an hour after purchasing it.

If you want a slightly faster boot time, use instead config(8), Any performance gains from customizing GENERIC will be *very* negligible.

Also, don't mess with the CFLAGS, while it's common practise for Linux users to add "optimizations", they're unnecessary and often *dangerous* when messed with.

It might depend on their background as to why some rebuild their kernel.
Some, like myself, may have come from FreeBSD (early releases) where the first thing you did was rebuild your kernel to enable/disable items you needed. IIRC, even pcm was disabled in GENERIC kernel. I would have to double-check my 3.x, 4.x cd's to verify, but the basic GENERIC kernel was very basic
I think the OpenBSD kernel would be similar to the older FreeBSD LINT kernel (hope I got the name right). A person copied needed items from that to a new kernel and rebuilt it.
Perhaps that's why some want to tinker. I had to build quite a few linux kernels in the earlier days so that even nowadays, the habit is strong enough to think of before I realize that I'm using OpenBSD and all I need to do is use "config -ef /bsd" to get what I want/need

Perhaps on the faq webpage, for the link to customizing a kernel, there should be a link to a page that just says "NO, DON'T, use config instead" and leave it at that
Reply With Quote
  #4   (View Single Post)  
Old 9th June 2008
ohauer ohauer is offline
Port Guard
 
Join Date: May 2008
Location: germany
Posts: 32
Thanked 2 Times in 2 Posts
Default

I can agree with Henning but i remember also an (for me) interesting thread that solves my problem with soekris and hifn (read the complete thread).
http://readlist.com/lists/openbsd.or.../12/61303.html

If i remember the card worked for me with 3.7/3.8, some trouble with 3.9 but was broken in 4.0/4,1 and the standart answer was 'it is the buggy hifn chip'
Reply With Quote
  #5   (View Single Post)  
Old 9th June 2008
ocicat ocicat is offline
Administrator
 
Join Date: Apr 2008
Posts: 2,888
Thanked 190 Times in 160 Posts
Default

Quote:
Originally Posted by unicyclist View Post
Some, like myself, may have come from FreeBSD (early releases) where the first thing you did was rebuild your kernel to enable/disable items you needed.
Although I understand your comparison, you are also contrasting FreeBSD when it was in its infancy, & there are significant differences between the project cultures today. You know, the whole apples & oranges thing...

The fact that there are non-BSD projects which promote compile happy mantras declaring "Compiler option tweaking is as good as flossing!" does everyone a disservice. The truth is that responsible tweaking requires understanding the ramifications of the decisions made, & this only comes from significant experience with studying the code. As has been stated in the same thread on misc@, shaving drivers doesn't really reduce the kernel's size by appreciable amounts.

Even tools like dmassage aren't that useful today as it only hunts through the output of dmesg(8) for "not configured" driver messages.

So the point on misc@ is that the developers are very jaded about efforts attempting to run the kernel in 1k as they have seen people dig themselves into very deep holes. While the code is available for anyone to do anything, just don't come crying when it has been broken.
Reply With Quote
  #6   (View Single Post)  
Old 11th June 2008
roundkat roundkat is offline
Shell Scout
 
Join Date: May 2008
Posts: 107
Thanked 1 Time in 1 Post
Default

I have watched /read Hennings' rants over the years..

He is like a Theo "light"
Reply With Quote
  #7   (View Single Post)  
Old 12th June 2008
cursedcompiler cursedcompiler is offline
New User
 
Join Date: Jun 2008
Posts: 7
Thanked 0 Times in 0 Posts
Default

usually it's best to stick with a generic kernel and default userland, but personally i always tweak little things here and there... i'd even say it is desirable in some situations (eg., low memory or slow and little boot media)
Reply With Quote
Reply

Thread Tools
Display Modes

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 On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
kernel file from 6.3 to 7.2 l2fl2f FreeBSD Installation and Upgrading 3 14th September 2009 06:53 PM
kernel version 0?? Stellar OpenBSD General 5 30th August 2009 11:07 PM
Poul-Henning Kamp (FreeBSD developer) sues Lenovo ;) vermaden FreeBSD General 9 17th August 2009 07:23 PM
kernel modules Mr-Biscuit FreeBSD General 0 2nd March 2009 06:18 AM
Do I need to Upgrade my Kernel yet Marred FreeBSD Ports and Packages 10 19th June 2008 05:33 PM


All times are GMT. The time now is 06:53 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content copyright © 2007-2010, the authors
Daemon image copyright ©1988, Marshall Kirk McKusick