Language Selection

English French German Italian Portuguese Spanish

Linux: CFS And Nice

Filed under
Linux

The recently merged Completely Fair Scheduler changes how the Linux kernel handles scheduling priorities set with the nice command. Ingo Molnar explained that each level of nice adds or substracts 10% of CPU utilization, "the '10% effect' is relative and cumulative: from _any_ nice level, if you go up 1 level, it's -10% CPU usage, if you go down 1 level it's +10% CPU usage." Ingo noted that with the earlier scheduler the nice level was tied to the HZ, offering three examples in which HZ is set to 100, 250, and 300, "a nice +19 task (the most commonly used nice level in practice) gets 9.1%, 3.9%, 3.1% of CPU time on the old scheduler, depending on the value of HZ. This is quite inconsistent and illogical. This HZ dependency of nice levels existed for many years, and the new scheduler solves that inconsistency - every nice level will get the same amount of time, regardless of HZ."

More Here.




More in Tux Machines

Security: Amazon, Microsoft, and John Draper

  • Amazon security camera could be remotely disabled by rogue couriers

    However, researchers from Rhino Security Labs found attacking the camera's Wi-Fi with a distributed denial of service attack, which sends thousands of information requests to the device, allowed them to freeze the camera. It would then continue to show the last frame broadcast, rather than going offline or alerting the user it had stopped working.

  • Pentagon contractor leaves social media spy archive wide open on Amazon
    A Pentagon contractor left a vast archive of social-media posts on a publicly accessible Amazon account in what appears to be a military-sponsored intelligence-gathering operation that targeted people in the US and other parts of the world. The three cloud-based storage buckets contained at least 1.8 billion scraped online posts spanning eight years, researchers from security firm UpGuard's Cyber Risk Team said in a blog post published Friday. The cache included many posts that appeared to be benign, and in many cases those involved from people in the US, a finding that raises privacy and civil-liberties questions. Facebook was one of the sites that originally hosted the scraped content. Other venues included soccer discussion groups and video game forums. Topics in the scraped content were extremely wide ranging and included Arabic language posts mocking ISIS and Pashto language comments made on the official Facebook page of Pakistani politician Imran Khan.
  • Pirated Microsoft Software Enabled NSA Hack says Kaspersky
    Earlier reports accused Kaspersky's antivirus software which was running on the NSA worker's home computer to be the reason behind the Russian spies to access the machine and steal important documents which belonged to NSA hacking unit, Equation Group.
  • Iconic hacker booted from conferences after sexual misconduct claims surface
    John Draper, a legendary figure in the world of pre-digital phone hacking known as "phreaking," has been publicly accused of inappropriate sexual behavior going back nearly two decades. According to a new Friday report by BuzzFeed News, Draper, who is also known as "Captain Crunch," acted inappropriately with six adult men and minors between 1999 and 2007 during so-called "energy" exercises, which sometimes resulted in private invitations to his hotel room. There, Draper allegedly made unwanted sexual advances. As a result of the new revelations, Draper, 74, is now no longer welcome at Defcon. Michael Farnum, the founder of HOU.SEC.CON, told Ars on Friday afternoon that Draper, who had been scheduled to speak in April 2018, was disinvited.

Debian Developers

  • Joey Hess: stupid long route
    Yesterday, I surpassed all that, and I did it in a way that hearkens right back to the original story. I had two computers, 20 feet apart, I wanted one to talk to the other, and the route between the two ended up traveling not around the Earth, but almost the distance to the Moon. I was rebuilding my home's access point, and ran into a annoying bug that prevented it from listening to wifi. I knew it was still connected over ethernet to the satellite receiver. I connected my laptop to the satellite receiver over wifi. But, I didn't know the IP address to reach the access point. Then I remembered I had set it up so incoming ssh to the satellite receiver was directed to the access point.
  • I am now a Debian Developer
    On the 6th of April 2017, I finally took the plunge and applied for Debian Developer status. On 1 August, during DebConf in Montréal, my application was approved. If you’re paying attention to the dates you might notice that that was nearly 4 months ago already. I was trying to write a story about how it came to be, but it ended up long. Really long (current draft is around 20 times longer than this entire post). So I decided I’d rather do a proper bio page one day and just do a super short version for now so that someone might end up actually reading it.
  • Freexian’s report about Debian Long Term Support, October 2017
    Like each month, here comes a report about the work of paid contributors to Debian LTS.

Programming: GNU Nano, Software Engineering Talent Shortage, HHVM (PHP)

  • GNU Nano Latest Version 2.9.0
    GNU nano 2.9.0 "Eta" introduces the ability to record and replay keystrokes (M-: to start and stop recording, M-; to play the macro back), makes ^Q and ^S do something useful by default (^Q starts a backward search, and ^S saves the current file), changes ^W to start always a forward search, shows the number of open buffers (when more than one) in the title bar, no longer asks to press Enter when there are errors in an rc file, retires the options '--quiet' and 'set quiet' and 'set backwards', makes indenting and unindenting undoable, will look in $XDG_CONFIG_HOME for a nanorc file and in $XDG_DATA_HOME for the history files, adds a history stack for executed commands (^R^X), does not overwrite the position-history file of another nano, and fixes a score of tiny bugs.
  • GNU Nano Text Editor Can Now Record & Replay Keystrokes
    GNU Nano 2.9 is now available as the latest feature release of this popular CLI text editor and it's bringing several new capabilities. First up, GNU Nano 2.9 has the ability to record and replay keystrokes within the text editor. M-: is used to start/stop the keystroke recording session while M-; is used to playback the macro / recorded keystrokes.
  • 2018's Software Engineering Talent Shortage— It’s quality, not just quantity

    The software engineering shortage is not a lack of individuals calling themselves “engineers”, the shortage is one of quality — a lack of well-studied, experienced engineers with a formal and deep understanding of software engineering.

  • HHVM 3.23
    HHVM 3.23 is released! This release contains new features, bug fixes, performance improvements, and supporting work for future improvements. Packages have been published in the usual places, however we have rotated the GPG key used to sign packages; see the installation instructions for more information.
  • Facebook Releases HHVM 3.23 With OpenSSL 1.1 Support, Experimental Bytecode Emitter
    HHVM 3.23 has been released as their high performance virtual machine for powering their Hack programming language and current PHP support. As mentioned back in September though, Facebook will stop focusing on PHP 7 compatibility in favor of driving their own Hack programming language forward. It's after their next release, HHVM 3.24, in early 2018 they will stop their commitment to supporting PHP5 features and at the same time not focus on PHP7 support. Due to the advancements made by upstream PHP on improving their performance, etc, Facebook is diverting their attention to instead just bolstering Hack and thus overtime the PHP support within HHVM will degrade.

Linux 4.14 File-System Benchmarks: Btrfs, EXT4, F2FS, XFS

Our latest Linux file-system benchmarking is looking at the performance of the mainline Btrfs, EXT4, F2FS, and XFS file-systems on the Linux 4.14 kernel compared to 4.13 and 4.12. In looking to see how the file-system/disk performance has changed if at all under the newly released Linux 4.14 kernel, I carried out some 4.12/4.13/4.14 benchmarks using Btrfs/EXT4/F2FS/XFS while freshly formatting the drive each time and using the default mount options. Read more Also: Freedreno Gallium3D Supports A Fair Amount Of OpenGL 4.x