My requirement is to do dynamic cpu shielding in C program based on the queue length of runnable threads (but not running threads which are waiting for CPU availability) in Realtime operating systems-(say ubuntu with RT linux patch) scenarios. For example, we can consider the system is configured for SCHED_FIFO policy.
I am not able to find any commands to retrieve the number of process which are in wait state, running state, runnable state etc.
Any help is much appreciated.
The command 'PS -T au' shows the state of all 'runnable' as well as 'running' threads as 'R'.
PS -T au
Below is the result I am getting from above command. In this ThreadID-16841, 16842 and 16843 are threads which were created by main process 16840. All the above created threads were showing in R state which denotes Runnable or running.
Instead I would like a linux command or C API to retrieve the number of processes in a runnable state but not running.
USER PID SPID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 914 914 0.1 1.3 428324 105804 tty7 Rsl+ Oct23 1:27 /usr/lib/xorg/Xorg -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten
root 914 925 0.0 1.3 428324 105804 tty7 Ssl+ Oct23 0:04 /usr/lib/xorg/Xorg -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten
root 1170 1170 0.0 0.0 23004 1772 tty1 Ss+ Oct23 0:00 /sbin/agetty --noclear tty1 linux
senthil 1979 1979 0.0 0.0 29532 5056 pts/11 Ss Oct23 0:00 bash
senthil 2032 2032 0.0 0.0 29552 5212 pts/2 Ss Oct23 0:00 bash
root 16837 16837 0.0 0.0 62092 4132 pts/2 S+ 09:37 0:00 sudo ./sigmain
root 16840 16840 0.0 0.0 31108 796 pts/2 Sl+ 09:37 0:00 ./sigmain
root 16840 16841 95.9 0.0 31108 796 pts/2 Rl+ 09:37 9:01 ./sigmain
root 16840 16842 95.9 0.0 31108 796 pts/2 Rl+ 09:37 9:01 ./sigmain
root 16840 16843 95.9 0.0 31108 796 pts/2 Rl+ 09:37 9:01 ./sigmain
senthil 17225 17225 0.0 0.0 44432 3364 pts/11 R+ 09:46 0:00 ps -T au