From: Martin Wilck <mwilck@xxxxxxxx>
We observe that multipath operations take a long time if the multipaths
section in multipath.conf contains a lot of alias settings
(10000+ in our case). This hurts in particular in udev rules, when
multipath -u or multipath -U is invoked, but also for command line
invocations like "multipath -ll".
This series provides a few optimizations for this use case. It speeds
up simple multipath operations in the test case by a factor of 20.
Changes wrt v1, after suggestions from Benjamin Marzinski:
01, 02: Use pointer comparisons to achieve stable sorting with qsort
02: Fix return without popping the cleanup handler. The way I fixed this
leaves the possibility that some memory won't be freed if a thread is
killed while executing vector_convert(). I think this is acceptible;
avoiding it would complicate the code, with very small benefit.
02: Remove unnecessary checks and break loop if alias==NULL is encountered.
Martin Wilck (3):
libmultipath: merge_mptable(): sort table by wwid
libmultipath: check_alias_settings(): pre-sort mptable by alias
multipath: optimize program startup for frequent invocations
libmultipath/alias.c | 44 ++++++++++++++++++++++++++++++++++++++++---
libmultipath/config.c | 24 +++++++++++++++++++++--
libmultipath/vector.c | 8 ++++++++
libmultipath/vector.h | 1 +
multipath/main.c | 33 ++++++++++++++++----------------
5 files changed, 89 insertions(+), 21 deletions(-)
--
2.37.1
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