projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 59121003 CL |
1 | # |
| 2 | # Timer Interrupt Frequency Configuration | |
| 3 | # | |
| 4 | ||
| 5 | choice | |
| 6 | prompt "Timer frequency" | |
| 7 | default HZ_250 | |
| 8 | help | |
| 9 | Allows the configuration of the timer frequency. It is customary | |
| 40fcfc87 | 10 | to have the timer interrupt run at 1000 Hz but 100 Hz may be more |
| 59121003 CL |
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 | |
| 40fcfc87 | 22 | 100 Hz is a typical choice for servers, SMP and NUMA systems |
| 59121003 CL |
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 | |
| 40fcfc87 | 29 | 250 Hz is a good compromise choice allowing server performance |
| 59121003 | 30 | while also showing good interactive responsiveness even |
| 40fcfc87 AC |
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. | |
| 59121003 CL |
41 | |
| 42 | config HZ_1000 | |
| 43 | bool "1000 HZ" | |
| 44 | help | |
| 40fcfc87 | 45 | 1000 Hz is the preferred choice for desktop systems and other |
| 59121003 CL |
46 | systems requiring fast interactive responses to events. |
| 47 | ||
| 48 | endchoice | |
| 49 | ||
| 50 | config HZ | |
| 51 | int | |
| 52 | default 100 if HZ_100 | |
| 53 | default 250 if HZ_250 | |
| 40fcfc87 | 54 | default 300 if HZ_300 |
| 59121003 CL |
55 | default 1000 if HZ_1000 |
| 56 | ||
| 8f4d37ec | 57 | config SCHED_HRTICK |
| 422037ba | 58 | def_bool HIGH_RES_TIMERS && USE_GENERIC_SMP_HELPERS |