recently I had to do some reports about scheduling processes in Linux, and to do so, we were asked to turn off all cpu except 0 to show how processes are running for cpu. But there is one thing which bothers me and I was asked about that during my oral exam. Why did process with round robin policy get cpu even if fifo has the same static priority, when I checked it second time, fifo got cpu ;/. Where I could eventually check for those answers ? I know that process or thread with FIFO policy can only be expropriated by RR policy process if the process has higher static priority but is it possible to somehow expropriate RR policy process ?
[root@ ttyid:0 śro maj 11 21:15:10 user]# (chrt -r 2 yes &);(chrt -f 2 yes &) [root@ ttyid:1 śro maj 11 21:15:32 user]# ps -o pid,cls,rtprio,sgi_p,psr,etime,cputime,tty,command,pcpu `pidof yes` PID CLS RTPRIO P PSR ELAPSED TIME TT COMMAND %CPU 4018 RR 2 * 0 01:37 00:00:02 pts/0 yes 2.9 4020 FF 2 * 0 01:37 00:00:00 pts/0 yes 0.0