Paolo Valente 44e44a1b32 block, bfq: improve responsiveness ... This patch introduces a simple heuristic to load applications quickly, and to perform the I/O requested by interactive applications just as quickly. To this purpose, both a newly-created queue and a queue associated with an interactive application (we explain in a moment how BFQ decides whether the associated application is interactive), receive the following two special treatments: 1) The weight of the queue is raised. 2) The queue unconditionally enjoys device idling when it empties; in fact, if the requests of a queue are sync, then performing device idling for the queue is a necessary condition to guarantee that the queue receives a fraction of the throughput proportional to its weight (see [1] for details). For brevity, we call just weight-raising the combination of these two preferential treatments. For a newly-created queue, weight-raising starts immediately and lasts for a time interval that: 1) depends on the device speed and type (rotational or non-rotational), and 2) is equal to the time needed to load (start up) a large-size application on that device, with cold caches and with no additional workload. Finally, as for guaranteeing a fast execution to interactive, I/O-related tasks (such as opening a file), consider that any interactive application blocks and waits for user input both after starting up and after executing some task. After a while, the user may trigger new operations, after which the application stops again, and so on. Accordingly, the low-latency heuristic weight-raises again a queue in case it becomes backlogged after being idle for a sufficiently long (configurable) time. The weight-raising then lasts for the same time as for a just-created queue. According to our experiments, the combination of this low-latency heuristic and of the improvements described in the previous patch allows BFQ to guarantee a high application responsiveness. [1] P. Valente, A. Avanzini, "Evolution of the BFQ Storage I/O Scheduler", Proceedings of the First Workshop on Mobile System Technologies (MST-2015), May 2015. http://algogroup.unimore.it/people/paolo/disk_sched/mst-2015.pdf Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>		2017-04-19 08:30:26 -06:00
..
ABI	block: remove the discard_zeroes_data flag	2017-04-08 11:25:38 -06:00
accounting	tools: move accounting tool from Documentation	2016-09-23 13:07:15 -06:00
acpi	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
admin-guide	Power management updates for v4.11-rc2	2017-03-09 16:30:37 -08:00
aoe
arm	arm: sunxi: add support for V3s SoC	2017-01-20 21:31:34 +01:00
arm64	irqchip/gicv3-its: Add workaround for QDF2400 ITS erratum 0065	2017-03-07 14:34:27 +00:00
auxdisplay	samples: move auxdisplay example code from Documentation	2016-09-23 11:52:32 -06:00
backlight
blackfin	samples: move blackfin gptimers-example from Documentation	2016-10-10 07:12:02 -06:00
block	block, bfq: improve responsiveness	2017-04-19 08:30:26 -06:00
blockdev	remove the mg_disk driver	2017-04-14 14:00:49 -06:00
bus-devices
cdrom	cdrom: Make device operations read-only	2017-02-14 08:29:56 -07:00
cgroup-v1	Merge branch 'for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2017-02-27 21:41:08 -08:00
cma
connector
console
core-api	Documentation: Update CPU hotplug and move it to core-api	2017-01-13 10:32:32 -07:00
cpu-freq	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
cpuidle
cris
crypto	crypto: doc - fix typo	2017-02-15 13:23:49 +08:00
dev-tools	scripts/spelling.txt: add "disble(d)" pattern and fix typo instances	2017-03-09 17:01:09 -08:00
device-mapper	scripts/spelling.txt: add "explictely" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
devicetree	USB/PHY fixes for 4.11-rc4	2017-03-26 10:52:52 -07:00
dmaengine	dmaengine: Documentation: Fix typo in pxa_dma.txt	2016-11-14 08:14:24 +05:30
doc-guide	docs-rst: parse-headers.pl: cleanup the documentation	2016-11-30 17:08:09 -07:00
DocBook	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
driver-api	Less anger inducing pull request for 4.11	2017-02-23 18:58:18 -08:00
driver-model	irqdesc: Add a resource managed version of irq_alloc_descs()	2017-02-10 14:39:20 +01:00
early-userspace
EDID
extcon	extcon: int3496: Add GPIO ACPI mapping table	2017-03-22 18:29:46 +09:00
fault-injection
fb
features	2nd round of ARC udpates for 4.10rc1	2016-12-23 10:22:47 -08:00
filesystems	statx: Add a system call to make enhanced file info available	2017-03-02 20:51:15 -05:00
firmware_class	firmware: revamp firmware documentation	2017-01-11 09:42:59 +01:00
fmc
fpga	fpga: Add scatterlist based programming	2017-02-10 15:20:44 +01:00
frv	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
gpio	gpio: random documentation update	2017-01-31 15:43:05 +01:00
gpu	Less anger inducing pull request for 4.11	2017-02-23 18:58:18 -08:00
hid	Documentation: HID: Intel ISH HID document	2016-08-17 11:13:07 +02:00
hwmon	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
i2c	i2c: i801: Add support for Intel Gemini Lake	2017-02-09 17:39:16 +01:00
ia64	selftests: move ia64 tests from Documentation/ia64	2016-09-20 09:58:12 -06:00
ide
iio	iio: Documentation: Correct the path used to create triggers.	2016-10-01 00:49:58 -06:00
infiniband	IB/hfi1: Document new sysfs entries for hfi1 driver	2016-10-02 08:42:19 -04:00
input	Documentation: input: fix path to input code definitions	2017-02-12 15:19:00 -07:00
ioctl	rpmsg updates for v4.11	2017-02-23 09:41:03 -08:00
isdn	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
kbuild	Kconfig: Introduce the "imply" keyword	2016-11-16 09:26:33 +01:00
kdump	Documentation: kdump: Add description of enable multi-cpus support	2016-09-20 18:02:54 -06:00
laptops	platform/x86: thinkpad_acpi: Add support for X1 Yoga (2016) Tablet Mode	2016-12-13 09:29:06 -08:00
leds	leds: class: Add new optional brightness_hw_changed attribute	2017-01-29 19:59:42 +01:00
lightnvm	lightnvm: physical block device (pblk) target	2017-04-16 10:06:33 -06:00
livepatch	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
locking	locking/ww_mutex/Documentation: Update the design document	2017-01-14 11:14:55 +01:00
m68k	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
md	MD: add doc for raid5-cache	2017-02-13 09:17:54 -08:00
media	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
memory-devices
metag
mic	samples: move mic/mpssd example code from Documentation	2016-09-20 12:38:48 -06:00
mips
misc-devices	samples: move misc-devices/mei example code from Documentation	2016-09-23 11:51:43 -06:00
mmc	mmc: core: Extend sysfs with DSR register	2016-07-25 10:34:51 +02:00
mn10300
mtd	spi-nor: Add support for Intel SPI serial flash controller	2017-01-03 17:33:36 +00:00
namespaces
netlabel
networking	Make IP 'forwarding' doc more precise	2017-03-12 23:28:43 -07:00
nfc
nios2
nvdimm
nvmem
parisc
PCI	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
pcmcia	tools: move pcmcia crc32hash tool from Documentation	2016-09-23 13:07:27 -06:00
perf	perf: add qcom l2 cache perf events driver	2017-02-08 19:32:24 +00:00
phy
platform
power	More power management updates for v4.11-rc1	2017-03-02 17:33:52 -08:00
powerpc	powerpc updates for 4.9	2016-10-07 20:19:31 -07:00
pps	Doc: clarify source of jitter in USB1.1, and USB2.0	2017-01-04 14:40:52 -07:00
prctl	selftests: move prctl tests from Documentation/prctl	2016-09-20 09:09:09 -06:00
process	Doc: Correct typo, "Introdution" => "Introduction"	2016-12-01 10:44:08 -07:00
pti
ptp	selftests: move ptp tests from Documentation/ptp	2016-09-20 09:54:38 -06:00
rapidio	rapidio/documentation/mport_cdev: add missing parameter description	2016-09-01 17:52:02 -07:00
RCU	Merge branches 'doc.2017.01.15b', 'dyntick.2017.01.23a', 'fixes.2017.01.23a', 'srcu.2017.01.25a' and 'torture.2017.01.15b' into HEAD	2017-01-25 12:56:05 -08:00
s390	Documentation: Update path to sysrq.txt	2017-03-03 15:48:38 -07:00
scheduler	sched/Documentation/sched-rt-group: Fix incorrect example	2017-01-22 10:34:17 +01:00
scsi	scripts/spelling.txt: add "varible" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
security	KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()	2017-03-02 10:09:00 +11:00
serial	Documentation: rs485: Do not define manually the ioctl	2016-08-18 11:08:33 -06:00
sh
sound	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
sparc	Documentation/sparc: Steps for sending break on sunhv console	2017-02-23 08:27:25 -08:00
sphinx	docs: sphinx-extensions: make rstFlatTable work with docutils 0.13	2016-12-18 13:30:29 -07:00
sphinx-static	This is the documentation update pull for the 4.9 merge window.	2016-10-04 13:54:07 -07:00
spi	spi: spi-ep93xx: simplify GPIO chip selects	2017-02-16 20:10:26 +00:00
sysctl	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
target
thermal	Documentation: fix spelling mistakes of "Celcius" -- > "Celsius"	2017-01-04 14:36:17 -07:00
timers	time: Remove CONFIG_TIMER_STATS	2017-02-10 11:15:08 +01:00
trace	perf/core: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS	2017-03-01 10:26:39 +01:00
translations	doc/ko_KR/memory-barriers: Update control-dependencies section	2017-03-03 15:54:55 -07:00
usb	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
virtual	KVM: Documentation: document MCE ioctls	2017-03-20 16:25:06 +01:00
vm	userfaultfd: non-cooperative: rollback userfaultfd_exit	2017-03-09 17:01:09 -08:00
w1
watchdog	watchdog: Introduce watchdog_stop_on_unregister helper	2017-02-24 14:00:23 -08:00
wimax
x86	Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-02-28 11:46:00 -08:00
xtensa	xtensa: cleanup MMU setup and kernel layout macros	2016-07-24 06:33:58 +03:00
.gitignore
00-INDEX	Documentation: move MD related doc into a separate dir	2017-02-13 09:17:53 -08:00
bcache.txt
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
cachetlb.txt
cgroup-v2.txt	cgroup: Fix indenting in PID controller documentation	2017-03-06 14:46:27 -05:00
Changes	docs: add back 'Documentation/Changes' file (as symlink)	2016-12-14 16:30:12 -08:00
circular-buffers.txt	Documentation: circular-buffers: use READ_ONCE()	2016-11-16 16:17:45 -07:00
clk.txt	Documentation: clk: update file names containing referenced structures	2016-08-14 12:12:36 -06:00
CodingStyle	doc: re-add CodingStyle and SubmittingPatches	2016-10-24 08:12:35 -02:00
conf.py	Documentation/sphinx: fix primary_domain configuration	2017-03-03 16:12:30 -07:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
digsig.txt
DMA-API-HOWTO.txt	Documentation: DMA-API-HOWTO: Fix a typo	2016-09-20 17:58:46 -06:00
DMA-API.txt	dma-mapping: add dma_{map,unmap}_resource	2016-09-26 22:16:41 +05:30
DMA-attributes.txt	common: DMA-mapping: add DMA_ATTR_PRIVILEGED attribute	2017-01-19 15:56:19 +00:00
DMA-ISA-LPC.txt	Documentation: DMA-ISA-LPC.txt	2017-02-12 15:20:07 -07:00
docutils.conf	doc-rst: add docutils config file	2016-08-14 11:52:40 -06:00
dontdiff	Documentation: dontdiff: Update with additional entries	2017-01-26 15:08:06 -07:00
efi-stub.txt
eisa.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcc-plugins.txt	gcc-plugins: update architecture list in documentation	2017-03-21 22:20:05 +11:00
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst	docs/zh_CN: Add coding-style into docs build system	2017-01-26 15:30:34 -07:00
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt	Documentation: Fix a typo in IPMI.txt.	2017-01-05 15:01:54 -06:00
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-doc-nano-HOWTO.txt	docs-rst: doc-guide: split the kernel-documentation.rst contents	2016-11-19 10:22:04 -07:00
kernel-per-CPU-kthreads.txt	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
kobject.txt
kprobes.txt	Documentation: kprobes: Document jprobes stack copying limitations	2016-08-15 10:19:11 -06:00
kref.txt
kselftest.txt	scripts/spelling.txt: add "an user" pattern and fix typo instances	2017-02-27 18:43:46 -08:00
ldm.txt
lockup-watchdogs.txt	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
logo.gif
logo.txt
lzo.txt
mailbox.txt
Makefile	samples: move blackfin gptimers-example from Documentation	2016-10-10 07:12:02 -06:00
Makefile.sphinx	Add a target to check broken external links in the Documentation	2017-02-15 15:22:47 -07:00
memory-barriers.txt	doc: Update control-dependencies section of memory-barriers.txt	2017-01-14 21:29:15 -08:00
memory-hotplug.txt	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
men-chameleon-bus.txt
nommu-mmap.txt
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pinctrl.txt	pinctrl: core: Fix regression caused by delayed work for hogs	2017-01-13 16:25:17 +01:00
pnp.txt
preempt-locking.txt
printk-formats.txt
pwm.txt
rbtree.txt
remoteproc.txt	remoteproc: Split driver and consumer dereferencing	2016-10-02 22:50:21 -07:00
rfkill.txt	docs: fix locations of several documents that got moved	2016-10-24 08:12:35 -02:00
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt	siphash: implement HalfSipHash1-3 for hash tables	2017-01-09 13:58:57 -05:00
SM501.txt
smsc_ece1099.txt
static-keys.txt	jump_label: Reduce the size of struct static_key	2017-02-15 09:02:26 -05:00
SubmittingPatches	doc: re-add CodingStyle and SubmittingPatches	2016-10-24 08:12:35 -02:00
svga.txt
sync_file.txt	dma-buf: Rename struct fence to dma_fence	2016-10-25 14:40:39 +02:00
this_cpu_ops.txt
unaligned-memory-access.txt	Documentation/unaligned-memory-access.txt: fix incorrect comparison operator	2016-12-27 13:08:42 -07:00
unshare.txt
vfio-mediated-device.txt	vfio-mdev: Make mdev_parent private	2016-12-30 08:13:41 -07:00
vfio.txt
video-output.txt
xillybus.txt
xz.txt
zorro.txt