Search results
Results from the WOW.Com Content Network
cgroups (abbreviated from control groups) is a Linux kernel feature that limits, accounts for, and isolates the resource usage (CPU, memory, disk I/O, etc. [1]) of a collection of processes. Engineers at Google started the work on this feature in 2006 under the name "process containers". [2]
Its CPU time "usage" is a measure of how much CPU time is not being used by other threads. In Windows 2000 and later the threads in the System Idle Process are also used to implement CPU power saving. The exact power saving scheme depends on the operating system version and on the hardware and firmware capabilities of the system in question ...
The term niceness itself originates from the idea that a process with a higher niceness value is nicer to other processes in the system and to users by virtue of demanding less CPU power—freeing up processing time and power for the more demanding programs, who would in this case be less nice to the system from a CPU usage perspective. [3]
Sometimes it is useful to convert CPU time into a percentage of the CPU capacity, giving the CPU usage. Measuring CPU time for two functionally identical programs that process identical inputs can indicate which program is faster, but it is a common misunderstanding that CPU time can be used to compare algorithms .
Round-robin algorithm is a pre-emptive algorithm as the scheduler forces the process out of the CPU once the time quota expires. For example, if the time slot is 100 milliseconds, and job1 takes a total time of 250 ms to complete, the round-robin scheduler will suspend the job after 100 ms and give other jobs their time on the CPU.
In DragonFly BSD 3.1 (2012) and later, usched utility can be used for assigning processes to a certain CPU set. [10] On Windows NT and its successors, thread and process CPU affinities can be set separately by using SetThreadAffinityMask [11] and SetProcessAffinityMask [12] API calls or via the Task Manager interface (for process affinity only).
For example, one can interpret a load average of "1.73 0.60 7.98" on a single-CPU system as: During the last minute, the system was overloaded by 73% on average (1.73 runnable processes, so that 0.73 processes had to wait for a turn for a single CPU system on average). During the last 5 minutes, the CPU was idling 40% of the time, on average.
Although the two-state process management model is a perfectly valid design for an operating system, the absence of a BLOCKED state means that the processor lies idle when the active process changes from CPU cycles to I/O cycles. This design does not make efficient use of the processor.