New: Swapping slows to about 20% of expected speed when using multiple swap partitions on separate drives (striping).
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Andrew Morton
maintainer(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface).
Quoted 7 lines · On Sat, 24 Feb 2018 03:56:38 +0000 [email protected] wrote:
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).
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. Let's get this onto the mm developers' mailing list and perhaps someone will have a theory. And perhaps Hugh will have a think about it when he returns to the fold.
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Quoted 27 lines · Andrew Morton
(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.
Quoted 3 lines
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.
Thanks, if let me know if you need me to run some test code or something.