[PATCH v4 0/3] block/diskstats: more accurate io_ticks and optimization

From: Konstantin Khlebnikov
Date: Wed Mar 25 2020 - 09:07:06 EST


Simplified estimation for io_ticks introduced in patch
https://lore.kernel.org/linux-block/20181206164122.2166-5-snitzer@xxxxxxxxxx/
could be very inaccurate for request longer than jiffy (i.e. any HDD)

There is at least one another report about this:
https://lore.kernel.org/linux-block/20200324031942.GA3060@xxxxxxxxxx/
See detail in comment for first patch.

v1: https://lore.kernel.org/lkml/155413438394.3201.15211440151043943989.stgit@buzz/
v2: https://lore.kernel.org/lkml/158314549775.1788.6529015932237292177.stgit@buzz/
v3: 158503038812.1955.7827988255138056389.stgit@buzz/">https://lore.kernel.org/lkml/158503038812.1955.7827988255138056389.stgit@buzz/
* update documentation
* rebase to current linux-next
* fix compilation for CONFIG_SMP=n
v4:
* rebase to for-5.7/block
* make part_stat_read_all static in block/genhd.c

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Konstantin Khlebnikov (3):
block/diskstats: more accurate approximation of io_ticks for slow disks
block/diskstats: accumulate all per-cpu counters in one pass
block/diskstats: replace time_in_queue with sum of request times


Documentation/admin-guide/iostats.rst | 5 +-
block/bio.c | 9 +--
block/blk-core.c | 5 +-
block/genhd.c | 109 +++++++++++++++++++++++----------
include/linux/genhd.h | 6 --
5 files changed, 88 insertions(+), 46 deletions(-)

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