Thomas Gleixner | ec8f24b | 2019-05-19 13:07:45 +0100 | [diff] [blame] | 1 | # SPDX-License-Identifier: GPL-2.0-only |
Christoph Lameter | 5912100 | 2005-06-23 00:08:25 -0700 | [diff] [blame] | 2 | # |
| 3 | # Timer Interrupt Frequency Configuration |
| 4 | # |
| 5 | |
| 6 | choice |
| 7 | prompt "Timer frequency" |
| 8 | default HZ_250 |
| 9 | help |
| 10 | Allows the configuration of the timer frequency. It is customary |
Alan Cox | 40fcfc8 | 2006-12-06 20:37:27 -0800 | [diff] [blame] | 11 | to have the timer interrupt run at 1000 Hz but 100 Hz may be more |
Christoph Lameter | 5912100 | 2005-06-23 00:08:25 -0700 | [diff] [blame] | 12 | beneficial for servers and NUMA systems that do not need to have |
| 13 | a fast response for user interaction and that may experience bus |
| 14 | contention and cacheline bounces as a result of timer interrupts. |
| 15 | Note that the timer interrupt occurs on each processor in an SMP |
| 16 | environment leading to NR_CPUS * HZ number of timer interrupts |
| 17 | per second. |
| 18 | |
| 19 | |
| 20 | config HZ_100 |
| 21 | bool "100 HZ" |
| 22 | help |
Alan Cox | 40fcfc8 | 2006-12-06 20:37:27 -0800 | [diff] [blame] | 23 | 100 Hz is a typical choice for servers, SMP and NUMA systems |
Christoph Lameter | 5912100 | 2005-06-23 00:08:25 -0700 | [diff] [blame] | 24 | with lots of processors that may show reduced performance if |
| 25 | too many timer interrupts are occurring. |
| 26 | |
| 27 | config HZ_250 |
| 28 | bool "250 HZ" |
| 29 | help |
Alan Cox | 40fcfc8 | 2006-12-06 20:37:27 -0800 | [diff] [blame] | 30 | 250 Hz is a good compromise choice allowing server performance |
Christoph Lameter | 5912100 | 2005-06-23 00:08:25 -0700 | [diff] [blame] | 31 | while also showing good interactive responsiveness even |
Alan Cox | 40fcfc8 | 2006-12-06 20:37:27 -0800 | [diff] [blame] | 32 | on SMP and NUMA systems. If you are going to be using NTSC video |
| 33 | or multimedia, selected 300Hz instead. |
| 34 | |
| 35 | config HZ_300 |
| 36 | bool "300 HZ" |
| 37 | help |
| 38 | 300 Hz is a good compromise choice allowing server performance |
| 39 | while also showing good interactive responsiveness even |
| 40 | on SMP and NUMA systems and exactly dividing by both PAL and |
| 41 | NTSC frame rates for video and multimedia work. |
Christoph Lameter | 5912100 | 2005-06-23 00:08:25 -0700 | [diff] [blame] | 42 | |
| 43 | config HZ_1000 |
| 44 | bool "1000 HZ" |
| 45 | help |
Alan Cox | 40fcfc8 | 2006-12-06 20:37:27 -0800 | [diff] [blame] | 46 | 1000 Hz is the preferred choice for desktop systems and other |
Christoph Lameter | 5912100 | 2005-06-23 00:08:25 -0700 | [diff] [blame] | 47 | systems requiring fast interactive responses to events. |
| 48 | |
| 49 | endchoice |
| 50 | |
| 51 | config HZ |
| 52 | int |
| 53 | default 100 if HZ_100 |
| 54 | default 250 if HZ_250 |
Alan Cox | 40fcfc8 | 2006-12-06 20:37:27 -0800 | [diff] [blame] | 55 | default 300 if HZ_300 |
Christoph Lameter | 5912100 | 2005-06-23 00:08:25 -0700 | [diff] [blame] | 56 | default 1000 if HZ_1000 |
| 57 | |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 58 | config SCHED_HRTICK |
Christoph Hellwig | 0a06ff0 | 2013-11-14 14:32:07 -0800 | [diff] [blame] | 59 | def_bool HIGH_RES_TIMERS |