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Commit 34cb711b authored by Andi Kleen's avatar Andi Kleen Committed by David S. Miller
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[NET]: Disable NET_SCH_CLK_CPU for SMP x86 hosts 



Opterons with frequency scaling have fully unsynchronized TSCs
running at different frequencies, so using TSCs there is not a good idea. 
Also some other x86 boxes have this problem. gettimeofday should be good 
enough, so just disable it.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c8923c6b

net/sched/Kconfig

+3 −1
Original line number Diff line number Diff line
@@ -72,9 +72,11 @@ config NET_SCH_CLK_GETTIMEOFDAY 
	  Choose this if you need a high resolution clock source but can't use

	  the CPU's cycle counter.



# don't allow on SMP x86 because they can have unsynchronized TSCs.

# gettimeofday is a good alternative

config NET_SCH_CLK_CPU

	bool "CPU cycle counter"

	depends on X86_TSC || X86_64 || ALPHA || SPARC64 || PPC64 || IA64

	depends on ((X86_TSC || X86_64) && !SMP) || 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