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In a June of 1992 posting to the linux-activists mailing list, Linus Torvalds described the original Linux scheduler noting, "the scheduler in linux is pretty simple, but does a reasonably good job at giving good IO response while not being too unfair against cpu-bound processes." A year later, Linus posted a more detailed description of the scheduler noting, "the linux scheduling algorithm is one of the simplest ones possible". Comments in the original 254 line sched.c file read, "'schedule()' is the scheduler function. This is GOOD CODE! There probably won't be any reason to change this, as it should work well in all circumstances (ie gives IO-bound processes good response etc). The one thing you might take a look at is the signal-handler code here." Comments in the current 6,709 line sched.c file show the first changes being made in 1996 by Dave Grothe, "to fix bugs in semaphores and make semaphores SMP safe". Two years later Andrea Arcangeli is credited with implementing "schedule_timeout() and related stuff". It was not until 2002, ten years after Linus' original code was written, that the scheduler received a complete rewrite, "new ultra-scalable O(1) scheduler by Ingo Molnar: hybrid priority-list and round-robin design with an array-switch method of distributing timeslices and per-CPU runqueues." Con Kolivas is credited with "interactivity tuning" in 2003, and Nick Piggin added "scheduler domains" in 2004. A more recent rewrite of the scheduler happened in April, again by Ingo Molnar, this time with his Completely Fair Scheduler. read more | Sponsor KernelTrap.org

In a June of 1992 posting to the linux-activists mailing list, Linus Torvalds described the original Linux scheduler noting, "the scheduler in linux is pretty simple, but does a reasonably good job at giving good IO response while not being too unfair against cpu-bound processes." A year later, Linus posted a more detailed description of the scheduler noting, "the linux scheduling algorithm is one of the simplest ones possible". Comments in the original 254 line sched.c file read, "'schedule()' is the scheduler function. This is GOOD CODE! There probably won't be any reason to change this, as it should work well in all circumstances (ie gives IO-bound processes good response etc). The one thing you might take a look at is the signal-handler code here." Comments in the current 6,709 line sched.c file show the first changes being made in 1996 by Dave Grothe, "to fix bugs in semaphores and make semaphores SMP safe". Two years later Andrea Arcangeli is credited with implementing "schedule_timeout() and related stuff". It was not until 2002, ten years after Linus' original code was written, that the scheduler received a complete rewrite, "new ultra-scalable O(1) scheduler by Ingo Molnar: hybrid priority-list and round-robin design with an array-switch method of distributing timeslices and per-CPU runqueues." Con Kolivas is credited with "interactivity tuning" in 2003, and Nick Piggin added "scheduler domains" in 2004. A more recent rewrite of the scheduler happened in April, again by Ingo Molnar, this time with his Completely Fair Scheduler. read more | Sponsor KernelTrap.org

In an overwhelmingly large series of 556 patches, Joe Perches attempted to track down maintainers for a significant number of files within the Linux kernel source tree. He explained, "I grew weary of looking up the appropriate maintainer email address(es) to CC: for a patch", adding a new line format to the kernel MAINTAINERS file parsed by a new get_maintainer.pl script. Much of the feedback was criticism of the large number of patches that flooded the inboxes of all subscribers to the Linux Kernel Mailing List. Others suggested that the information would be better extracted from Git than from source files. When Joe asked for better ideas for achieving his end goal, Alan Cox suggested, "working off the git tree as it shows who actually is making changes/updating stuff recently and why which is a major clue when tracing bugs". Chris Wright pointed out, "I think this data will easily become stale. What is the point again?" going on to add "between git (or gitweb), existing MAINTAINERS and a bit of common sense (or extra sleuthing), I never perceived a significant problem." Adrian Bunk countered, "for active kernel developers like you and me it's not a problem. But for other people it's non-trivial to always figure out who the maintainer of some part of the kernel is." read more | rsync.net - Secure Offsite Data

This Blog is for the Novice techie's to learn Linux Kernel through their personal experience.

hi, i am trying to find out the interrupt latency for the linux-2.6.14, can anyone tell me what is the procedure to test latency and the code used to test it? please help me out to achieve this job....

A bottleneck is quite literally a small part of your installation (hardware or software), where too much processing is being funneled through a specific area. In other words, far too much is going on in one particular area of an installation, in comparison with any other part. read more | rsync.net - Offsite Unix Backups