Alexander Motin f8020c9363 Make metaslab class rotor and aliquot per-allocator. ... Metaslab rotor and aliquot are used to distribute workload between vdevs while keeping some locality for logically adjacent blocks. Once multiple allocators were introduced to separate allocation of different objects it does not make much sense for different allocators to write into different metaslabs of the same metaslab group (vdev) same time, competing for its resources. This change makes each allocator choose metaslab group independently, colliding with others only sporadically. Test including simultaneous write into 4 files with recordsize of 4KB on a striped pool of 30 disks on a system with 40 logical cores show reduction of vdev queue lock contention from 54 to 27% due to better load distribution. Unfortunately it won't help much ZVOLs yet since only one dataset/ZVOL is synced at a time, and so for the most part only one allocator is used, but it may improve later. While there, to reduce the number of pointer dereferences change per-allocator storage for metaslab classes and groups from several separate malloc()'s to variable length arrays at the ends of the original class and group structures. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Signed-off-by: Alexander Motin <mav@FreeBSD.org> Closes #11288		2020-12-15 10:55:44 -08:00
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.gitignore	Add .gitignore files to exclude build products	2010-01-08 11:35:17 -08:00
Makefile.am	Unconditionally enable debugging for libzpool	2020-07-10 15:30:31 -07:00
ztest.c	Make metaslab class rotor and aliquot per-allocator.	2020-12-15 10:55:44 -08:00