Hi Christophe,
Please consider this series of patches.
This series of patches help to make IO processing more common for
path-latency prioritizer, make the multipath.conf more user-friendly
and fixup the error of calculation on log scale standard deviation.
First, the SCSI-to-NVMe translations which was blamed broken has been removed
since linux kernel 4.13, so that SG_IO IOCTL used in the reading is not
supported. Instead, PATCH 1/4 drops sg_read method and uses direct IO
reading both for NVMe device and SCSI device.
Second, the original prio_args for prioritizer is like this: 20|10 which
is somewhat unconvenient for user. PATCH 3/4 drops it and use a syntax that
similar to other prioritizers, for example :
"base_num=5 io_num=10".
PATCH 2/4 can be an independent patch.
Third, Martin has pointed that standard deviation in the path-latency prioritizer
is wrong. We have solved this and here come the PATCH 4/4.
Thanks
Guan Junxiong
Changes from V1:
* add PATCH 4/4
* rebase on the 0.7.3 tag
Junxiong Guan (3):
multipath-tools: use direct IO for path latency prioritizer
multipath-tools: move get_next_string to util
multipath-tools: use user-friendly prio_args for path-latency
libmultipath/prioritizers/path_latency.c | 156 +++++++++++++++++++++++--------
libmultipath/prioritizers/weightedpath.c | 10 +-
libmultipath/util.c | 9 ++
libmultipath/util.h | 1 +
multipath/multipath.conf.5 | 2 +-
5 files changed, 127 insertions(+), 51 deletions(-)
Guan Junxiong (4):
multipath-tools: use direct IO for path latency prioritizer
multipath-tools: move get_next_string to util
multipath-tools: use user-friendly prio_args for path-latency
multipath-tools: calculate standard deviation on a logarithmic scale
for prioritizer path_latency
libmultipath/prioritizers/path_latency.c | 321 ++++++++++++++++++++-----------
libmultipath/prioritizers/weightedpath.c | 10 +-
libmultipath/util.c | 9 +
libmultipath/util.h | 1 +
multipath/multipath.conf.5 | 2 +-
5 files changed, 217 insertions(+), 126 deletions(-)
--
2.11.1
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