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Questions tagged [cfs]

Completely Fair Scheduler (CFS) is the default CPU Linux scheduler

The Completely Fair Scheduler (CFS) is a process scheduler which was merged into the 2.6.23 release of the Linux kernel and is the default scheduler. It handles CPU resource allocation for executing processes, and aims to maximize overall CPU utilization while also maximizing interactive performance.

See here for further details.

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Kubernetes CPU quotas and process scheduling behavior

Given a Pod defining a container that runs a single-threaded application, and a CPU limit value of 1: apiVersion: v1 kind: Pod metadata: name: single-threaded-workload spec: containers: - name: microservice image: single-threaded-workload …
MichaelAttard
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Does every single CPU core own a red-black tree for CFS?

CFS scheduler uses red-black lock to hold the processes to be scheduled, i am not sure whether there is a global tree or one tree for one CPU core? I think the later is more efficient, but i can not find any proof.
sion
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How to get delta percentage from /proc/schedstat

I am trying to get node CFS scheduler throttling in percent. For that i am reading 2 values 2 times (ignoring timeslices) from /proc/schedstat it has following format: $ cat /proc/schedstat version 15 timestamp 4297299139 cpu0 0 0 0 0 0 0…
xakepp35
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docker-compose spec says cpus option is deprecated but docker run says use --cpus

Reading docker-compose spec (https://github.com/compose-spec/compose-spec/blob/master/spec.md#cpus) it says that cpus option is DEPRECATED, so even if it still works when I use it, I think it is not a great idea. cpus DEPRECATED: use…
Roberto Iglesias
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hardware implementation of algorithms using in os scheduler

1.in os when a new process comes , does hardware make interrupts (while another process is running) for os to create a new PCB data structure for this new process ? 2.Consider Completely Fair Scheduling (CFS) algorithms : when a process is…
ققنوس
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Use of signal_pending_state function to change task's state to TASK_RUNNING

I was going over through the main scheduling function: __schedule() and found a code snippet which is: if (!preempt && prev->state) { if (unlikely(signal_pending_state(prev->state, prev))) { prev->state = TASK_RUNNING; …
Lucifer Poltergeist
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Calling task_tick_fair in CFS algorithm

Why is there a for_each_sched_entity macro in task_tick_fair function called on system tick? According to me, only the run time characteristics of the current task should be updated. Why does it call entity_tick for the entire hierarchy of the…
Lucifer Poltergeist
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How a RT process can release the CPU for CFS processes, and get it back when there are no ready CFS processes

A question about scheduling in Linux: I have several processes scheduled with CFS and one process "A" that is running with Real-Time (RT) (SCHED_FIFO) scheduling - all process are bind to one specific CPU core. The process "A" is running on RT…
user1868481
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Which kernel function manages balancing the RB-tree of the linux CFS?

From what I have understood so far about the Linux CFS is that scheduling entities are indexed by their virtual runtime (vruntime) inside the RB-tree. The scheduler regularly updates this vruntime by calling the update_curr function which basically…
Tyrann
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Ubuntu can't find fair.c of kernel/sched

I am trying to find fair.c file to look at source code to improve CFS algorithm. In the internet, many advised to look at kernel/sched folder. However, there was only Makefile file. I am running ubuntu 16.0.4 on virtual box and kernel version is…
Chol Min Kang
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sched_wakeup_granularity_ns in CFS correctly designed or not?

I was working on the Linux CFS scheduler and came across this tuneable parameter called sched_wakeup_granularity_ns. The use of this goes as follows as described in this paper. This parameter controls the wake-up latency of a task, i.e., the amount…
Rohith R
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Generating periodic workloads with deadlines in linux (NON-RT OS)

I want to run some tasks which are periodic and have certain deadlines. I want to see how the linux scheduler (CFS) handles these tasks. I don't want a Real-Time OS for this but I want to see how a normal linux system reacts to these kinds of…
Rohith R
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How to solve 'Secondary indexes cardinality' for cfs.inode?

In OpsCenter 6.0.3, I got the following problem The above figure appeared after clicking 'Services' -> 'Best Practice Service' -> 'Performance Service - Table Metrics Advisor' -> 'Secondary indexes cardinality' in turn. The inode table viewed in…
feng1122
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How to display images of a array?

I'm using these packages aldeed:collection2, aldeed:autoform, cfs:standard-packages, yogiben:autoform-file, cfs:filesystem. {{#with FS.GetFile "images" pictures}} …
Bryan Zamora
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insert metadata to image collection CFS METEOR

i have the method to resize in meteor CFS, like the page. var createThumb = function(fileObj, readStream, writeStream) { // Transform the image into a 10x10px thumbnai gm(readStream, fileObj.name()).size({ bufferStream: true }, function(err,…
Levan Lacroix
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