New: Swapping slows to about 20% of expected speed when using multiple swap partitions on separate drives (striping).

https://bugzilla.kernel.org/show_bug.cgi?id=198913

Bug ID: 198913
Summary: Swapping slows to about 20% of expected speed when
using multiple swap partitions on separate drives (striping).

...

Problems
1) Linux's swap striping on nine drives performs at only 19.5% of the speed of a memory-mapped file on a RAID 0 partition on the same nine drives.
2) Linux's swap striping performs best with exactly four swap partitions and performs almost as well with just three partitions.

(switched to email.A A Please respond via emailed reply-to-all, not via the
bugzilla web interface).

Quoted 12 lines · On Sat, 24 Feb 2018 03:56:38 +0000 [email protected] g wrote:

https://bugzilla.kernel.org/show_bug.cgi?id=198913

A A A A A A A A A A A A Bug ID: 198913
A A A A A A A A A A A Summary: Swapping slows to about 20% of expected speed when
A A A A A A A A A A A A A A A A A A A A using multiple swap partitions on separate drives
A A A A A A A A A A A A A A A A A A A A (striping).

...

Quoted 8 lines

Problems
1) Linux's swap striping on nine drives performs at only 19.5% of the speed of
a memory-mapped file on a RAID 0 partition on the same nine drives.
2) Linux's swap striping performs best with exactly four swap partitions and
performs almost as well with just three partitions.

Well that's interesting, thanks.A A Let's get this onto the mm developers' mailing list and perhaps someone will have a theory.A A And perhaps Hugh will have a think about it when he returns to the fold.