Yuchung Cheng e33099f96d tcp: implement RFC5682 F-RTO ... This patch implements F-RTO (foward RTO recovery): When the first retransmission after timeout is acknowledged, F-RTO sends new data instead of old data. If the next ACK acknowledges some never-retransmitted data, then the timeout was spurious and the congestion state is reverted. Otherwise if the next ACK selectively acknowledges the new data, then the timeout was genuine and the loss recovery continues. This idea applies to recurring timeouts as well. While F-RTO sends different data during timeout recovery, it does not (and should not) change the congestion control. The implementaion follows the three steps of SACK enhanced algorithm (section 3) in RFC5682. Step 1 is in tcp_enter_loss(). Step 2 and 3 are in tcp_process_loss(). The basic version is not supported because SACK enhanced version also works for non-SACK connections. The new implementation is functionally in parity with the old F-RTO implementation except the one case where it increases undo events: In addition to the RFC algorithm, a spurious timeout may be detected without sending data in step 2, as long as the SACK confirms not all the original data are dropped. When this happens, the sender will undo the cwnd and perhaps enter fast recovery instead. This additional check increases the F-RTO undo events by 5x compared to the prior implementation on Google Web servers, since the sender often does not have new data to send for HTTP. Note F-RTO may detect spurious timeout before Eifel with timestamps does so. Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2013-03-21 11:47:51 -04:00
..
ABI	batman-adv: network coding - add the initial infrastructure code	2013-03-13 22:53:48 +01:00
accounting	doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c	2012-11-26 14:22:21 +01:00
acpi	ACPI / Documentation: refer to correct file for acpi_platform_device_ids[] table	2013-02-13 13:43:02 +01:00
aoe	aoe: allow user to disable target failure timeout	2012-12-17 17:15:25 -08:00
arm	fbdev changes for 3.8:	2012-12-15 13:03:48 -08:00
arm64	arm64: Add simple earlyprintk support	2013-01-22 17:51:01 +00:00
auxdisplay
backlight	backlight: lp855x_bl: support new LP8557 device	2013-02-21 17:22:25 -08:00
blackfin	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
block	cfq-iosched: enable full blkcg hierarchy support	2013-01-09 08:05:11 -08:00
blockdev	nbd: update documentation and link to mailinglist	2013-02-27 19:10:22 -08:00
bus-devices	ARM: OMAP2+: gpmc: generic timing calculation	2012-11-09 18:07:11 +05:30
cdrom
cgroups	Merge branch 'for-3.9/core' of git://git.kernel.dk/linux-block	2013-02-28 12:52:24 -08:00
connector	connector: Move cn_test.c away from NLMSG_PUT().	2012-06-26 21:19:02 -07:00
console
cpu-freq	cpufreq: Update Documentation for cpus and related_cpus	2013-02-02 00:01:16 +01:00
cpuidle	Honor state disabling in the cpuidle ladder governor	2012-09-04 01:35:44 +02:00
cris	CRIS: Update documentation	2012-04-03 13:09:18 +02:00
crypto	KEYS: Document asymmetric key type	2012-10-08 13:50:12 +10:30
development-process	Documentation: Update stable address	2011-12-12 14:14:31 -08:00
device-mapper	md updates for 3.9	2013-03-05 17:22:08 -08:00
devicetree	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2013-03-20 12:46:26 -04:00
DocBook	Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux	2013-02-25 16:46:44 -08:00
driver-model	lib: devres: Introduce devm_ioremap_resource()	2013-01-22 09:41:43 -08:00
dvb	[media] get_dvb_firmware: Fix the location of firmware for Terratec HTC	2013-01-01 11:18:26 -02:00
early-userspace
EDID	drm: Load EDID: Explain better how to write your own EDID firmware	2013-01-20 19:22:19 +10:00
extcon	Documentation/extcon: porting guide for Android kernel switch driver.	2012-04-20 09:24:27 -07:00
fault-injection	doc: fix quite a few typos within Documentation	2012-11-19 14:28:24 +01:00
fb	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
filesystems	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-02-26 20:16:07 -08:00
firmware_class	firmware loader: document firmware cache mechanism	2012-11-14 15:07:18 -08:00
frv
hid	HID: remove x bit from sensor doc	2012-12-14 08:48:59 +01:00
hwmon	hwmon: (lm75) Fix tcn75 prefix	2013-03-18 21:19:49 +01:00
i2c	i2c: i801: Add Device IDs for Intel Wellsburg PCH	2013-02-15 20:46:01 +01:00
i2o	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
ia64	doc: aliasing-test: close fd on write error	2012-09-01 09:57:10 -07:00
ide	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
infiniband	IB/ipoib: Add rtnl_link_ops support	2012-09-20 16:49:17 -04:00
input	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2013-03-11 07:49:37 -07:00
ioctl	wanrouter: completely decouple obsolete code from kernel.	2013-01-31 19:20:33 -05:00
isdn	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
ja_JP
kbuild	Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild	2013-02-27 12:28:30 -08:00
kdump	kexec: update URL of kexec homepage	2012-07-18 18:35:57 -07:00
ko_KR	driver-core: documentation: fix up Greg's email address	2012-02-15 14:48:01 -08:00
laptops	Documentation/laptops: remove depends on CONFIG_EXPERIMENTAL	2013-01-21 14:52:42 -08:00
leds	Documentation: leds: update LP55xx family devices	2013-02-06 15:59:30 -08:00
m68k
make
memory-devices	memory: emif: add basic infrastructure for EMIF driver	2012-05-02 00:10:49 -07:00
metag	metag: Basic documentation	2013-03-02 20:09:50 +00:00
mips
misc-devices	doc: fix quite a few typos within Documentation	2012-11-19 14:28:24 +01:00
mmc	mmc: core: Extend sysfs to ext_csd parameters for RPMB support	2012-12-06 13:54:48 -05:00
mn10300
mtd
namespaces	userns: Recommend use of memory control groups.	2013-01-26 22:20:06 -08:00
netlabel
networking	tcp: implement RFC5682 F-RTO	2013-03-21 11:47:51 -04:00
nfc	NFC: Update pn544 documentation	2013-01-10 01:27:46 +01:00
parisc	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
PCI	PCI/MSI: Enable multiple MSIs with pci_enable_msi_block_auto()	2013-01-24 17:25:13 +01:00
pcmcia
power	PM / OPP: improve introductory documentation	2013-03-04 14:23:11 +01:00
powerpc	powerpc: Documentation for transactional memory on powerpc	2013-02-15 17:02:25 +11:00
pps
prctl	seccomp: Make syscall skipping and nr changes more consistent	2012-10-02 21:14:29 +10:00
pti
ptp
rapidio	RapidIO: documentation update	2011-11-02 16:07:02 -07:00
RCU	Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD	2012-11-16 09:59:58 -08:00
s390	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
scheduler	sched: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW	2012-09-13 16:52:04 +02:00
scsi	[SCSI] megaraid_sas: Version and Changelog update	2013-02-22 15:37:15 +00:00
security	Documentation: fix Documentation/security/00-INDEX	2012-12-17 17:15:22 -08:00
serial	tty: Update serial core API documentation	2013-01-15 21:57:44 -08:00
sh
sound	ALSA: compress: add support for gapless playback	2013-02-14 12:30:22 +01:00
spi	Documentation: remove __dev* attributes.	2013-01-03 15:57:16 -08:00
sysctl	Documentation/sysctl/kernel.txt: document /proc/sys/shmall	2013-01-04 16:11:46 -08:00
target	target: Simplify fabric sense data length handling	2012-09-17 17:12:58 -07:00
thermal	Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux	2013-02-28 19:48:26 -08:00
timers
trace	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-03-11 07:54:29 -07:00
usb	USB: report submission of active URBs	2012-11-11 18:10:46 -08:00
vDSO
video4linux	[media] radio-si470x doc: add info about v4l2-ctl and sox+alsa	2013-02-13 17:33:20 -02:00
virtual	Merge tag 'kvm-3.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm	2013-02-24 13:07:18 -08:00
vm	ksm: add some comments	2013-02-23 17:50:23 -08:00
w1	w1: w1_therm: Add force-pullup option for "broken" sensors	2013-02-18 13:55:24 -08:00
watchdog	watchdog: core: dt: add support for the timeout-sec dt property	2013-03-01 12:48:36 +01:00
wimax
x86	Merge branch 'x86/microcode' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-02-22 19:22:52 -08:00
xtensa	xtensa: initialize atomctl SR	2012-12-18 21:10:22 -08:00
zh_CN	Driver core patches for 3.9-rc1	2013-02-21 12:05:51 -08:00
.gitignore
00-INDEX	ImgTec Meta architecture changes for v3.9-rc1	2013-03-03 12:06:09 -08:00
applying-patches.txt
atomic_ops.txt	Documentation: Memory barrier semantics of atomic_xchg()	2013-01-08 14:14:55 -08:00
bad_memory.txt
basic_profiling.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt
Changes
circular-buffers.txt
clk.txt	Documentation: common clk API	2012-03-16 20:35:01 +00:00
coccinelle.txt	coccicheck: Allow the user to give a V= (verbose) argument	2013-02-22 11:39:13 +01:00
CodingStyle	Documentation: remove depends on CONFIG_EXPERIMENTAL	2013-01-11 11:38:03 -08:00
cpu-hotplug.txt	doc: Add x86 CPU0 online/offline feature	2012-11-14 09:39:44 -08:00
cpu-load.txt
cputopology.txt
crc32.txt	crc32: move long comment about crc32 fundamentals to Documentation/	2012-03-23 16:58:37 -07:00
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt	firmware: remove last vestiges of dabusb	2012-11-21 13:03:01 -08:00
digsig.txt	crypto: digital signature verification support	2011-11-09 12:10:37 +02:00
DMA-API-HOWTO.txt	Documentation/DMA-API-HOWTO.txt: fix typo	2013-02-27 19:10:23 -08:00
DMA-API.txt	dma-debug: New interfaces to debug dma mapping errors	2012-10-24 17:06:43 +02:00
DMA-attributes.txt	common: DMA-mapping: add DMA_ATTR_FORCE_CONTIGUOUS attribute	2012-11-29 03:30:34 -08:00
dma-buf-sharing.txt	dma-buf: implement vmap refcounting in the interface logic	2013-02-27 15:13:36 +05:30
DMA-ISA-LPC.txt
dmaengine.txt	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
dontdiff	x86: remove offsets.h from .gitignore and dontdiff	2012-11-19 14:10:53 +01:00
dynamic-debug-howto.txt	dynamic_debug: dynamic hex dump	2013-01-17 12:19:09 -08:00
edac.txt	Merge branch 'devel'	2012-07-29 21:11:05 -03:00
eisa.txt	MCA: delete all remaining traces of microchannel bus support.	2012-05-17 19:06:13 -04:00
email-clients.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gpio.txt	gpiolib: provide provision to register pin ranges	2012-11-11 19:06:00 +01:00
highuid.txt
HOWTO	HOWTO: fix double words typo	2012-12-10 15:54:27 +01:00
hw_random.txt
hwspinlock.txt
init.txt
initrd.txt	Documentation/initrd.txt: Change the location of util-linux	2012-05-25 16:18:34 +02:00
intel_txt.txt	Documentation: remove depends on CONFIG_EXPERIMENTAL	2013-01-11 11:38:03 -08:00
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt	ipmi: add options to disable openfirmware and PCI scanning	2013-02-27 19:10:21 -08:00
IRQ-affinity.txt
IRQ-domain.txt	irqdomain: update documentation	2012-12-05 23:52:10 +00:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt	Kernel-doc: Convention: Use a "Return" section to describe return values	2012-11-27 21:08:57 +01:00
kernel-docs.txt
kernel-parameters.txt	ImgTec Meta architecture changes for v3.9-rc1	2013-03-03 12:06:09 -08:00
kmemcheck.txt
kmemleak.txt	kmemleak: Handle percpu memory allocation	2011-12-02 16:12:42 +00:00
kobject.txt	Documentation: Fix "struct kobj_type" to include newer members.	2012-09-04 16:06:34 -07:00
kprobes.txt
kref.txt	kref: Add kref_get_unless_zero documentation	2012-11-28 18:36:06 +10:00
ldm.txt
local_ops.txt
lockdep-design.txt	lockdep: Update documentation for lock-class leak detection	2011-12-11 10:31:23 -08:00
lockstat.txt	locking/stat: Fix a typo	2013-02-19 08:42:37 +01:00
lockup-watchdogs.txt	watchdog: Update documentation	2012-02-11 15:11:28 +01:00
logo.gif
logo.txt
magic-number.txt	wanrouter: completely decouple obsolete code from kernel.	2013-01-31 19:20:33 -05:00
Makefile	mei: move doc files Documentation/misc-devices/mei	2012-05-09 13:59:09 -07:00
ManagementStyle	Documentation: ManagementStyle: fixed typo	2012-06-28 12:03:15 +02:00
md.txt	md: create externally visible flags for supporting hot-replace.	2011-12-23 10:17:51 +11:00
media-framework.txt	[media] Documentation/media-framework.txt: fix a sentence	2013-02-08 13:27:13 -02:00
memory-barriers.txt	Documentation: Memory barrier semantics of atomic_xchg()	2013-01-08 14:14:55 -08:00
memory-hotplug.txt	hotplug: update nodemasks management	2012-12-12 17:38:33 -08:00
mono.txt	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
mutex-design.txt
nommu-mmap.txt
numastat.txt	Doc: Update numastat.txt	2012-02-28 16:05:06 +01:00
oops-tracing.txt	module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree	2011-11-07 07:54:42 +10:30
padata.txt
parport-lowlevel.txt
parport.txt	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
percpu-rw-semaphore.txt	percpu-rw-semaphore: fix documentation typos	2012-09-26 19:56:15 +02:00
pi-futex.txt
pinctrl.txt	drivers/pinctrl: grab default handles from device core	2013-01-23 16:39:51 +01:00
pnp.txt
preempt-locking.txt
printk-formats.txt	Randy has moved	2013-03-08 15:05:34 -08:00
pwm.txt	pwm: add devm_pwm_get() and devm_pwm_put()	2012-09-10 17:05:45 +02:00
ramoops.txt	pstore/ftrace: Convert to its own enable/disable debugfs knob	2012-09-06 22:16:58 -07:00
rbtree.txt	rbtree: move augmented rbtree functionality to rbtree_augmented.h	2012-10-09 16:22:40 +09:00
remoteproc.txt	remoteproc: add rproc_report_crash function to notify rproc crashes	2012-09-18 12:53:22 +03:00
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt	Documentation: remove __dev* attributes.	2013-01-03 15:57:16 -08:00
rt-mutex-design.txt
rt-mutex.txt
rtc.txt	rtc-proc: permit the /proc/driver/rtc device to use other devices	2012-10-06 03:05:01 +09:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
SM501.txt
smsc_ece1099.txt	mfd: smsc: Add support for smsc gpio io/keypad driver	2012-10-01 15:27:48 +02:00
sparse.txt	Documentation/sparse.txt: document context annotations for lock checking	2012-12-17 17:15:23 -08:00
spinlocks.txt
stable_api_nonsense.txt
stable_kernel_rules.txt	stable: Allow merging of backports for serious user-visible performance issues	2012-06-25 12:11:58 -07:00
static-keys.txt	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
SubmitChecklist
SubmittingDrivers
SubmittingPatches	Randy has moved	2013-03-08 15:05:34 -08:00
svga.txt
sysfs-rules.txt
sysrq.txt	sparc64: Add global PMU register dumping via sysrq.	2012-10-16 09:34:01 -07:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt	vfio: Trivial Documentation correction	2012-09-21 10:48:03 -06:00
VGA-softcursor.txt
vgaarbiter.txt	misc latin1 to utf8 conversions	2012-01-02 13:04:55 +01:00
video-output.txt
vme_api.txt	VME: Move API documentation to Documentation folder	2012-05-08 16:01:34 -07:00
volatile-considered-harmful.txt
workqueue.txt	workqueue: reimplement WQ_HIGHPRI using a separate worker_pool	2012-07-13 22:24:45 -07:00
xz.txt
zorro.txt