Merge to Fedora Core 2 kernel-2.6.8-1.521

[linux-2.6.git] / net / sched / Kconfig

diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 54817b8..97a42d9 100644 (file)
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -1,6 +1,61 @@
 #
 # Traffic control configuration.
 # 
+choice
+       prompt "Packet scheduler clock source"
+       depends on NET_SCHED
+       default NET_SCH_CLK_JIFFIES
+       help
+         Packet schedulers need a monotonic clock that increments at a static
+         rate. The kernel provides several suitable interfaces, each with
+         different properties:
+         
+         - high resolution (us or better)
+         - fast to read (minimal locking, no i/o access)
+         - synchronized on all processors
+         - handles cpu clock frequency changes
+
+         but nothing provides all of the above.
+
+config NET_SCH_CLK_JIFFIES
+       bool "Timer interrupt"
+       help
+         Say Y here if you want to use the timer interrupt (jiffies) as clock
+         source. This clock source is fast, synchronized on all processors and
+         handles cpu clock frequency changes, but its resolution is too low
+         for accurate shaping except at very low speed.
+
+config NET_SCH_CLK_GETTIMEOFDAY
+       bool "gettimeofday"
+       help
+         Say Y here if you want to use gettimeofday as clock source. This clock
+         source has high resolution, is synchronized on all processors and
+         handles cpu clock frequency changes, but it is slow.
+
+         Choose this if you need a high resolution clock source but can't use
+         the CPU's cycle counter.
+
+config NET_SCH_CLK_CPU
+       bool "CPU cycle counter"
+       depends on X86_TSC || X86_64 || ALPHA || SPARC64 || PPC64 || IA64
+       help
+         Say Y here if you want to use the CPU's cycle counter as clock source.
+         This is a cheap and high resolution clock source, but on some
+         architectures it is not synchronized on all processors and doesn't
+         handle cpu clock frequency changes.
+
+         The useable cycle counters are:
+
+               x86/x86_64      - Timestamp Counter
+               alpha           - Cycle Counter
+               sparc64         - %ticks register
+               ppc64           - Time base
+               ia64            - Interval Time Counter
+
+         Choose this if your CPU's cycle counter is working properly.
+
+endchoice
+
 config NET_SCH_CBQ
        tristate "CBQ packet scheduler"
        depends on NET_SCHED
@@ -158,7 +213,9 @@ config NET_SCH_NETEM
          testing applications or protocols.
 
          To compile this driver as a module, choose M here: the module
-         will be called sch_delay.
+         will be called sch_netem.
+
+         If unsure, say N.
 
 config NET_SCH_INGRESS
        tristate "Ingress Qdisc"