General Scraps

• Processor priority in Linux
• The first is the nice value, a number from -20 to +19 with a default of 0. Larger nice values correspond to a lower priorityyou are being nice to the other processes on the system. Processes with a lower nice value (higher priority) run before processes with a higher nice value (lower priority). The nice value also helps determine how long a timeslice the process receives. A process with a nice value of -20 receives the maximum possible timeslice, whereas a process with a nice value of 19 receives the minimum possible timeslice. Nice values are the standard priority range used in all Unix systems.
• The second range is the real-time priority. The values are configurable, but by default range from 0 to 99. All real-time processes are at a higher priority than normal processes.
• Real Time values + nice value together.
• Real Time process command
• http://linux.die.net/man/1/chrt
• http://unix.stackexchange.com/questions/154867/real-time-processes-scheduling-in-linux
• The chrt command
• To set scheduling policy to SCHED_FIFO, enter:

  chrt -f -p [1..99] {pid}
  

  To set scheduling policy to SCHED_RR, enter:

  chrt -r -p [1..99] {pid}

• asmlinkage keyworkd in system call

• system call is reentrant

• Seeing assembly and register values in GDB and description about assembly code

                  https://www.recurse.com/blog/7-understanding-c-by-learning-assembly

• re-entrant and thread safe functions.
• https://www.ibm.com/support/knowledgecenter/ssw_aix_61/com.ibm.aix.genprogc/writing_reentrant_thread_safe_code.htm
• Variadic functions and variadic macro funtions
• Volatile type specifier - http://www.geeksforgeeks.org/understanding-volatile-qualifier-in-c/