3 ms·

How so?

• PaulDavisThe1st 3y ago
  In the 90s, the cost of choosing the wrong thread to run when another thread blocked was significant in specific kinds of applications. Since then, the cost has (in absolute terms) gone down, the number of applications for which this is true has not really increased. In addition, there has been some expansion in the number of applications for which SCHED_RT and SCHED_FIFO are appropriate for at least some threads (financial services high speed trading, real time audio), which has also reduced the pressure for a user-space scheduler that "gets it right". This is also true for designs which require guaranteed scheduling slots. So, SA might still bring some benefits to large, highly-threaded monolithic apps such as RDBMS, but it doesn't really provide much to the majority of contemporary applications. It certainly doesn't do much for mobile environments, which tend not to run applications where "the application knows best".
  • vacuity 3y ago
    Makes sense. Ideally the OS should provide the capability to do SA (or similar), but I don't know how the overhead would be for programs that opt out of using it.