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

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

[Andrew Morton]

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

On Sat, 24 Feb 2018 03:56:38 +0000 bugzilla-daemon@bugzilla.kernel.org 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).
> 
> ...
>
> 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.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

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

[Dan]

[-- Attachment #1: Type: text/plain, Size: 1224 bytes --]

On Tue, 2018-03-06 at 16:23 -0800, Andrew Morton wrote:
> (switched to email.A A Please respond via emailed reply-to-all, not via
> the
> bugzilla web interface).
> 
> On Sat, 24 Feb 2018 03:56:38 +0000 bugzilla-daemon@bugzilla.kernel.or
> 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).
> > 
> > ...
> > 
> > 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.
Thanks, if let me know if you need me to run some test code or
something.

[-- Attachment #2: Type: text/html, Size: 1386 bytes --]