kernel_optimize_test/include
David S. Miller 7adc3830f9 [TCP]: Improve ipv4 established hash function.
If all of the entropy is in the local and foreign addresses,
but xor'ing together would cancel out that entropy, the
current hash performs poorly.

Suggested by Cosmin Ratiu:

	Basically, the situation is as follows: There is a client
	machine and a server machine. Both create 15000 virtual
	interfaces, open up a socket for each pair of interfaces and
	do SIP traffic. By profiling I noticed that there is a lot of
	time spent walking the established hash chains with this
	particular setup.

	The addresses were distributed like this: client interfaces
	were 198.18.0.1/16 with increments of 1 and server interfaces
	were 198.18.128.1/16 with increments of 1. As I said, there
	were 15000 interfaces. Source and destination ports were 5060
	for each connection.  So in this case, ports don't matter for
	hashing purposes, and the bits from the address pairs used
	cancel each other, meaning there are no differences in the
	whole lot of pairs, so they all end up in the same hash chain.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-04 14:28:41 -08:00
..
acpi
asm-alpha
asm-arm spi: pxa2xx_spi clock polarity fix 2008-02-23 17:12:14 -08:00
asm-avr32
asm-blackfin
asm-cris
asm-frv FRV: Change the timerfd syscalls to be the same as i386 2008-02-20 19:58:16 -08:00
asm-generic percpu: fix DEBUG_PREEMPT per_cpu checking 2008-02-23 12:09:28 -08:00
asm-h8300 h8300: IRQ handling update 2008-02-23 17:12:16 -08:00
asm-ia64
asm-m32r
asm-m68k
asm-m68knommu
asm-mips Alchemy: compile fix 2008-02-24 20:03:42 +01:00
asm-mn10300 MN10300: define SO_MARK 2008-02-23 17:12:13 -08:00
asm-parisc
asm-powerpc percpu: fix DEBUG_PREEMPT per_cpu checking 2008-02-23 12:09:28 -08:00
asm-ppc
asm-s390
asm-sh
asm-sparc
asm-sparc64
asm-um
asm-v850
asm-x86 Remove empty file remnants that were left in the tree by mistake 2008-02-20 19:56:01 -08:00
asm-xtensa
crypto
keys
linux [NETPOLL]: Revert two bogus cleanups that broke netconsole. 2008-03-04 12:28:49 -08:00
math-emu
media
mtd
net [TCP]: Improve ipv4 established hash function. 2008-03-04 14:28:41 -08:00
pcmcia
rdma
rxrpc
scsi
sound [ALSA] opl3 - Fix compilation without sequencer support 2008-02-22 14:20:08 -08:00
video
xen
Kbuild