[PATCH] i386: Selectable Frequency of the Timer Interrupt

[cascardo/linux.git] / kernel / Kconfig.hz

diff --git a/kernel/Kconfig.hz b/kernel/Kconfig.hz
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+#
+# Timer Interrupt Frequency Configuration
+#
+
+choice
+       prompt "Timer frequency"
+       default HZ_250
+       help
+        Allows the configuration of the timer frequency. It is customary
+        to have the timer interrupt run at 1000 HZ but 100 HZ may be more
+        beneficial for servers and NUMA systems that do not need to have
+        a fast response for user interaction and that may experience bus
+        contention and cacheline bounces as a result of timer interrupts.
+        Note that the timer interrupt occurs on each processor in an SMP
+        environment leading to NR_CPUS * HZ number of timer interrupts
+        per second.
+
+
+       config HZ_100
+               bool "100 HZ"
+       help
+         100 HZ is a typical choice for servers, SMP and NUMA systems
+         with lots of processors that may show reduced performance if
+         too many timer interrupts are occurring.
+
+       config HZ_250
+               bool "250 HZ"
+       help
+        250 HZ is a good compromise choice allowing server performance
+        while also showing good interactive responsiveness even
+        on SMP and NUMA systems.
+
+       config HZ_1000
+               bool "1000 HZ"
+       help
+        1000 HZ is the preferred choice for desktop systems and other
+        systems requiring fast interactive responses to events.
+
+endchoice
+
+config HZ
+       int
+       default 100 if HZ_100
+       default 250 if HZ_250
+       default 1000 if HZ_1000
+