Alexander Motin 86706441a8 Introduce write-mostly sums ... wmsum counters are a reduced version of aggsum counters, optimized for write-mostly scenarios. They do not provide optimized read functions, but instead allow much cheaper add function. The primary usage is infrequently read statistic counters, not requiring exact precision. The Linux implementation is directly mapped into percpu_counter KPI. The FreeBSD implementation is directly mapped into counter(9) KPI. In user-space due to lack of better implementation mapped to aggsum. Unfortunately neither Linux percpu_counter nor FreeBSD counter(9) provide sufficient functionality to completelly replace aggsum, so it still remains to be used for several hot counters. Reviewed-by: Paul Dagnelie <pcd@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Ryan Moeller <ryan@iXsystems.com> Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored-By: iXsystems, Inc. Closes #12114		2021-05-27 14:27:29 -06:00
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freebsd	Introduce write-mostly sums	2021-05-27 14:27:29 -06:00
linux	Introduce write-mostly sums	2021-05-27 14:27:29 -06:00
Makefile.am	Add FreeBSD support to OpenZFS	2020-04-14 11:36:28 -07:00