LinuxQuestions.org
Share your knowledge at the LQ Wiki.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Software > Linux - Kernel
User Name
Password
Linux - Kernel This forum is for all discussion relating to the Linux kernel.

Notices


Reply
  Search this Thread
Old 07-04-2013, 10:31 AM   #1
mreff555
Member
 
Registered: Sep 2011
Location: Philly
Distribution: Gentoo
Posts: 473

Rep: Reputation: Disabled
Timer Tick Handling


Newer kernel version have more options about Tick Handling

Code:
Timer tick handling
  1. Periodic timer ticks (constant rate, no dynticks) (HZ_PERIODIC) (NEW)
> 2. Idle dynticks system (tickless idle) (NO_HZ_IDLE) (NEW)
  3. Full dynticks system (tickless) (NO_HZ_FULL) (NEW)
choice[1-3]:
I can infer a few things. I would guess that dynamic tics would be less accurate with the benefit of speed. Based on this I would think periodic would be the best choice for most desktop systems, but I would like some more insite in to this.
 
Old 07-05-2013, 02:35 PM   #2
crosstalk
Member
 
Registered: Jul 2010
Distribution: Gentoo, Debian, Mint, Xubuntu
Posts: 150

Rep: Reputation: 35
Dynamic ticks shuts off the normal periodic timer interrupt when a logical CPU is otherwise idle. This is no less accurate than periodic ticks -- however, it decreases power usage (often significantly) when the system is idle (and a periodic tick is unnecessary). This is actually a good idea on a desktop system.

Full dynamic ticks additionally shuts off the periodic interrupt when only one process is runnable on a given logical CPU. This may potentially improve performance for high-throughput tasks (perhaps latency-sensitive tasks as well?) if process affinities are set by hand. In essence, this lets someone who really cares about performance give a process full control of a logical CPU. This would also be an acceptable option for desktop systems.

In short, you probably won't notice a difference between NO_HZ_IDLE and NO_HZ_FULL, so choose whichever you want. I'd recommend against HZ_PERIODIC because it would increase power usage (it prevents a processor from going to sleep for any significant amount of time).
 
  


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
Tick, jiffies and time interpolation Kirilla Linux - Kernel 1 02-27-2009 08:04 AM
LXer: Just what makes Linux tick LXer Syndicated Linux News 0 02-21-2008 08:50 PM
How can I get LAPIC timer to run instead of the PIT timer? sixerjman Linux - Kernel 1 10-16-2007 09:59 PM
Multimedia timer (SMP friendly timer) bigqueso Linux - Kernel 0 03-15-2007 03:49 PM
dm won't tick in services Boffy Mandriva 3 09-23-2004 04:06 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Software > Linux - Kernel

All times are GMT -5. The time now is 01:06 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