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A Unix process scheduler doesn't really "piggy back" on a system call. Executing the scheduler is part of just about any system call. A read() system call or an exit() system call absolutely has to cause the scheduler to execute. In the case of a read() a disk access might take a very long time. Unless you want everything to be very slow, you need to run ...


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Question 1 It is possible for an user to use real time priority for a process as well. This configuration could be set from /etc/security/limits.conf file. I see the below contents in that file. # /etc/security/limits.conf # #Each line describes a limit for a user in the form: # #<domain> <type> <item> <value> If we ...


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I am wondering why top and htop don't display -100 for higest priority real time processes ? That's because SCHED_RR and SCHED_FIFO have fixed static priorities from 1-99: Source For realtime priorities, the order is reversed: 99 is indeed the highest one, contrary to the ususal "lower is higher". Per your comment I misunderstood your question, ...


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Have the at-script call itself once it's done. # cat t.txt true cat t.txt | at 9am mon # bash t.txt warning: commands will be executed using /bin/sh job 680 at Mon Sep 8 09:00:00 2014 # Just replace true with your actual script.


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at can only schedule a command to be run once. You can get around this be making the job schedule itself again, as well as executing your command. Example: ~/myJob.txt: at -f ~/myJob.txt +1 week ; echo "It's 9:00 AM on Monday!" Then you just schedule it once to begin the cycle: at -f ~/myJob.txt 9am monday


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Yep, your processor does a NOP (No Op) or HLT Linux uses an idle process. This task does nothing but sends HLT and makes the CPU use less power and heat while there is nothing to do. Then when there is work to be done the CPU "comes back on" and does work. Now, keep in mind that the Linux scheduler will do "any work it can" before that point. This HLTing ...


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According to the same Wikipedia article, "the primary abstraction known by the kernel is still a process," which would imply that scheduling for POSIX threads is the same as other processes in Linux. There are differences, however, in the way in which the POSIX threads handle synchronization, which is what spurred the development of NPTL in the first place. ...


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You can put files in your /etc/cron.d as root (or if you are have sudo). You could do something like this ... # cat > /etc/cron.d/mycronjob <<EOT * * * * * /bin/logger "Hello from cron" EOT ... then you can watch your cron job write the system log like so ... # tail -f /var/log/messages


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Each user has their own scheduled tasks. If you go and pick your kid from school at 4pm every day, your neighbor doesn't also go and pick your kid at 4pm. Cron jobs can be registered by each user (in which case they run with that user's privileges) or at the system level (in which case they run as a user chosen by the system administrator). Each scheduled ...



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