Konstantin Khlebnikov 2b8bd42361 block/diskstats: more accurate approximation of io_ticks for slow disks ... Currently io_ticks is approximated by adding one at each start and end of requests if jiffies counter has changed. This works perfectly for requests shorter than a jiffy or if one of requests starts/ends at each jiffy. If disk executes just one request at a time and they are longer than two jiffies then only first and last jiffies will be accounted. Fix is simple: at the end of request add up into io_ticks jiffies passed since last update rather than just one jiffy. Example: common HDD executes random read 4k requests around 12ms. fio --name=test --filename=/dev/sdb --rw=randread --direct=1 --runtime=30 & iostat -x 10 sdb Note changes of iostat's "%util" 8,43% -> 99,99% before/after patch: Before: Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sdb 0,00 0,00 82,60 0,00 330,40 0,00 8,00 0,96 12,09 12,09 0,00 1,02 8,43 After: Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sdb 0,00 0,00 82,50 0,00 330,00 0,00 8,00 1,00 12,10 12,10 0,00 12,12 99,99 Now io_ticks does not loose time between start and end of requests, but for queue-depth > 1 some I/O time between adjacent starts might be lost. For load estimation "%util" is not as useful as average queue length, but it clearly shows how often disk queue is completely empty. Fixes: 5b18b5a737 ("block: delete part_round_stats and switch to less precise counting") Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>		2020-03-25 08:49:08 -06:00
..
ABI	xen: branch for v5.6-rc1	2020-02-05 17:44:14 +00:00
EDID	docs: driver-api: add a series of orphaned documents	2019-07-15 11:03:02 -03:00
PCI	Documentation: PCI: Fix pci_alloc_irq_vectors() function name typo	2019-12-30 08:21:29 -06:00
RCU	Merge branches 'doc.2019.12.10a', 'exp.2019.12.09a', 'fixes.2020.01.24a', 'kfree_rcu.2020.01.24a', 'list.2020.01.10a', 'preempt.2020.01.24a' and 'torture.2019.12.09a' into HEAD	2020-01-24 10:37:27 -08:00
accounting	docs: add some documentation dirs to the driver-api book	2019-07-15 11:03:02 -03:00
admin-guide	block/diskstats: more accurate approximation of io_ticks for slow disks	2020-03-25 08:49:08 -06:00
arm	ARM: at91: Documentation: add sam9x60 product and datasheet	2020-01-10 23:40:31 +01:00
arm64	mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()	2020-02-20 10:03:14 +00:00
block	block: Document genhd capability flags	2020-03-12 07:47:22 -06:00
bpf	bpf: Add s390 testing documentation	2019-10-30 16:25:31 +01:00
cdrom	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
core-api	mm, tree-wide: rename put_user_page*() to unpin_user_page*()	2020-01-31 10:30:38 -08:00
cpu-freq	Documentation: cpufreq: Update policy notifier documentation	2019-09-02 22:44:05 +02:00
crypto	crypto: algapi - make unregistration functions return void	2019-12-20 14:58:35 +08:00
dev-tools	Documentation: kunit: fixed sphinx error in code block	2020-02-10 17:16:42 -07:00
devicetree	ARM: SoC fixes	2020-03-08 17:36:22 -07:00
doc-guide	Documentation: build warnings related to missing blank lines after explicit markups has been fixed	2020-02-05 10:30:03 -07:00
driver-api	dmaengine fixes for v5.6-rc5	2020-03-05 12:19:34 -06:00
fault-injection	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
fb	fbdev: fbmem: allow overriding the number of bootup logos	2020-01-03 14:27:40 +01:00
features	s390 updates for the 5.6 merge window #2	2020-02-05 17:33:35 +00:00
filesystems	Driver core / debugfs fixes for 5.6-rc5	2020-03-08 10:39:40 -05:00
firmware-guide	docs: firmware-guide: ACPI: Replace dma_request_slave_channel() with dma_request_chan()	2019-12-19 22:58:12 +01:00
firmware_class	…
fpga	Documentation: fpga: dfl: add descriptions for thermal/power management interfaces	2019-10-16 19:18:26 -07:00
gpu	drm-misc-next for v5.6:	2020-01-03 11:43:44 +10:00
hid	docs: add some documentation dirs to the driver-api book	2019-07-15 11:03:02 -03:00
hwmon	docs: adm1177: fix a broken reference	2020-02-23 20:00:29 -08:00
i2c	docs: i2c: writing-clients: properly name the stop condition	2020-01-29 22:02:09 +01:00
ia64	docs: add SPDX tags to new index files	2019-07-15 11:03:03 -03:00
ide	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
iio	docs: add some documentation dirs to the driver-api book	2019-07-15 11:03:02 -03:00
infiniband	Documentation/infiniband: update name of some functions	2019-09-13 16:55:55 -03:00
input	Input: docs: fix spelling mistake "potocol" -> "protocol"	2019-08-06 11:24:49 -06:00
isdn	isdn: capi: dead code removal	2019-12-11 09:12:38 +01:00
kbuild	kbuild: get rid of trailing slash from subdir- example	2020-02-27 10:03:27 +09:00
kernel-hacking	Documentation: kernel-hacking: hacking.rst: Change reference to document namespaces.rst to symbol-namespaces.rst	2019-12-19 09:36:23 -07:00
leds	leds: core: Add support for composing LED class device names	2019-07-25 20:07:52 +02:00
livepatch	livepatch: Documentation of the new API for tracking system state changes	2019-11-01 13:08:24 +01:00
locking	docs/locking: Fix outdated section names	2020-02-05 10:21:12 -07:00
m68k	docs: README.buddha: convert to ReST and add to m68k book	2019-07-31 13:30:10 -06:00
maintainer	Add a maintainer entry profile for documentation	2020-01-24 09:48:39 -07:00
media	media updates for v5.6-rc1	2020-01-31 14:43:23 -08:00
mic	docs: driver-api: add remaining converted dirs to it	2019-07-15 11:03:03 -03:00
mips	docs: fix some broken references	2019-10-10 11:25:39 -06:00
misc-devices	Documentation: fix Sphinx warning in xilinx_sdfec.rst	2019-12-19 09:26:25 -07:00
netlabel	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
networking	docs: networking: phy: Rephrase paragraph for clarity	2020-02-23 20:42:47 -08:00
nios2	docs: nios2: add it to the main Documentation body	2019-07-31 13:31:51 -06:00
nvdimm	docs: nvdimm: use ReST notation for subsection	2020-01-24 09:54:42 -07:00
openrisc	docs: openrisc: convert to ReST and add to documentation body	2019-07-31 13:30:20 -06:00
parisc	docs: parisc: convert to ReST and add to documentation body	2019-07-31 13:30:15 -06:00
pcmcia	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
power	Documentation: power: Drop reference to interface.rst	2020-02-20 11:50:59 +01:00
powerpc	powerpc updates for 5.6	2020-02-04 13:06:46 +00:00
process	Documentation/process: Swap out the ambassador for Canonical	2020-02-13 15:38:41 -08:00
riscv	It has been a relatively quiet cycle for documentation, but there's still a	2020-01-29 15:27:31 -08:00
s390	Documentation/s390: remove outdated debugging390 documentation	2019-08-21 12:41:43 +02:00
scheduler	Documentation/scheduler: fix links in sched-stats	2019-10-29 04:35:41 -06:00
scsi	scsi: simplify scsi_partsize	2020-03-24 07:57:07 -06:00
security	Documentation: security: core.rst: fix warnings	2019-11-22 10:01:47 -07:00
sh	docs: remove extra conf.py files	2019-07-17 06:57:52 -03:00
sound	sound updates for 5.6-rc1	2020-01-28 16:26:57 -08:00
sparc	docs: add arch doc directories to the index	2019-07-15 11:03:01 -03:00
sphinx	docs: Fix empty parallelism argument	2020-02-25 03:11:04 -07:00
sphinx-static	doc-rst: Reduce CSS padding around Field	2019-10-02 10:03:06 -06:00
spi	spi: docs: convert to ReST and add it to the kABI bookset	2019-07-31 14:13:13 -06:00
target	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
timers	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
trace	A handful of small documentation fixes that wandered in.	2020-02-07 13:03:10 -08:00
translations	Documentation/process: Swap out the ambassador for Canonical	2020-02-13 15:38:41 -08:00
usb	docs: usb: remove some broken references	2020-01-28 13:41:22 -07:00
userspace-api	staging: remove isdn capi drivers	2019-12-11 09:11:29 +01:00
virt	KVM: s390: rstify new ioctls in api.rst	2020-02-24 19:28:40 +01:00
vm	mm/zswap.c: add allocation hysteresis if pool limit is hit	2020-01-31 10:30:39 -08:00
w1	docs: w1: Fix a typo in omap-hdq.rst	2019-12-30 11:58:02 -07:00
watchdog	linux-watchdog 5.4-rc1 tag	2019-09-27 11:17:38 -07:00
x86	docs: remove MPX from the x86 toc	2020-02-25 03:10:22 -07:00
xtensa	docs: add arch doc directories to the index	2019-07-15 11:03:01 -03:00
.gitignore	…
COPYING-logo	docs: logo.txt: rename it to COPYING-logo	2019-07-15 09:20:27 -03:00
Changes	…
CodingStyle	…
DMA-API-HOWTO.txt	docs: DMA-API-HOWTO.txt: fix an unmarked code block	2019-07-15 09:20:24 -03:00
DMA-API.txt	dma-mapping: remove dma_release_declared_memory	2019-09-04 11:13:19 +02:00
DMA-ISA-LPC.txt	…
DMA-attributes.txt	dma-mapping: remove the DMA_ATTR_WRITE_BARRIER flag	2019-11-14 12:01:54 -04:00
IPMI.txt	…
IRQ-affinity.txt	…
IRQ-domain.txt	…
IRQ.txt	…
Kconfig	docs: Kbuild/Makefile: allow check for missing docs at build time	2019-06-07 11:33:16 -06:00
Makefile	Kbuild updates for v5.5	2019-12-02 17:35:04 -08:00
SubmittingPatches	…
asm-annotations.rst	Documentation: Call out example SYM_FUNC_* usage as x86-specific	2020-01-16 12:53:16 -07:00
atomic_bitops.txt	…
atomic_t.txt	Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2019-07-08 16:12:03 -07:00
bus-virt-phys-mapping.txt	…
conf.py	doc-rst: Programmatically render MAINTAINERS into ReST	2019-10-02 10:03:17 -06:00
crc32.txt	…
debugging-modules.txt	…
debugging-via-ohci1394.txt	…
digsig.txt	…
docutils.conf	doc-rst: Add missing newline at end of file	2019-06-20 14:16:56 -06:00
dontdiff	modpost: dump missing namespaces into a single modules.nsdeps file	2019-11-11 20:10:01 +09:00
futex-requeue-pi.txt	…
hwspinlock.txt	hwspinlock: add the 'in_atomic' API	2019-06-29 21:08:14 -07:00
index.rst	Here's the main documentation changes for 5.5:	2019-12-02 11:51:02 -08:00
io-mapping.txt	…
io_ordering.txt	…
irqflags-tracing.txt	…
kobject.txt	…
kprobes.txt	…
kref.txt	…
logo.gif	…
lzo.txt	…
mailbox.txt	…
memory-barriers.txt	smp_mb__{before,after}_atomic(): update Documentation	2020-02-04 03:05:23 +00:00
nommu-mmap.txt	…
percpu-rw-semaphore.txt	…
pi-futex.txt	docs: locking: convert docs to ReST and rename to *.rst	2019-07-15 08:53:27 -03:00
preempt-locking.txt	…
rbtree.txt	docs: rbtree.txt: fix Sphinx build warnings	2019-07-15 09:20:24 -03:00
remoteproc.txt	remoteproc: add vendor resources handling	2019-06-29 12:02:17 -07:00
robust-futex-ABI.txt	…
robust-futexes.txt	…
rpmsg.txt	…
speculation.txt	…
static-keys.txt	…
tee.txt	Documentation: tee: add AMD-TEE driver details	2020-01-04 13:49:51 +08:00
this_cpu_ops.txt	…
unaligned-memory-access.txt	…
xz.txt	…