1# 2# Timer Interrupt Frequency Configuration 3# 4 5choice 6 prompt "Timer frequency" 7 default HZ_250 8 help 9 Allows the configuration of the timer frequency. It is customary 10 to have the timer interrupt run at 1000 Hz but 100 Hz may be more 11 beneficial for servers and NUMA systems that do not need to have 12 a fast response for user interaction and that may experience bus 13 contention and cacheline bounces as a result of timer interrupts. 14 Note that the timer interrupt occurs on each processor in an SMP 15 environment leading to NR_CPUS * HZ number of timer interrupts 16 per second. 17 18 19 config HZ_100 20 bool "100 HZ" 21 help 22 100 Hz is a typical choice for servers, SMP and NUMA systems 23 with lots of processors that may show reduced performance if 24 too many timer interrupts are occurring. 25 26 config HZ_250 27 bool "250 HZ" 28 help 29 250 Hz is a good compromise choice allowing server performance 30 while also showing good interactive responsiveness even 31 on SMP and NUMA systems. If you are going to be using NTSC video 32 or multimedia, selected 300Hz instead. 33 34 config HZ_300 35 bool "300 HZ" 36 help 37 300 Hz is a good compromise choice allowing server performance 38 while also showing good interactive responsiveness even 39 on SMP and NUMA systems and exactly dividing by both PAL and 40 NTSC frame rates for video and multimedia work. 41 42 config HZ_1000 43 bool "1000 HZ" 44 help 45 1000 Hz is the preferred choice for desktop systems and other 46 systems requiring fast interactive responses to events. 47 48endchoice 49 50config HZ 51 int 52 default 100 if HZ_100 53 default 250 if HZ_250 54 default 300 if HZ_300 55 default 1000 if HZ_1000 56 57config SCHED_HRTICK 58 def_bool HIGH_RES_TIMERS && (!SMP || USE_GENERIC_SMP_HELPERS) 59