Re: [PATCH] DM-CRYPT: Scale to multiple CPUs

[Tomasz Chmielewski]

Milan Broz wrote:

> On 05/31/2010 06:04 PM, Andi Kleen wrote:
> > DM-CRYPT: Scale to multiple CPUs
> >
> > Currently dm-crypt does all encryption work per dmcrypt mapping in a
> > single workqueue. This does not scale well when multiple CPUs
> > are submitting IO at a high rate. The single CPU running the single
> > thread cannot keep up with the encryption and encrypted IO performance
> > tanks.
>
> This is true only if encryption run on the CPU synchronously.
>
> (Usually it is high speed SSD or dm-crypt above striped RAID where
> underlying device throughput is higher than CPU encryption speed.)

Quite common to hit on a netbook/laptop with encrypted root these days, 
where storage can be relatively fast when compared to the speed of one 
of the cores of the (usually) multicore CPU.


--
Tomasz Chmielewski
http://wpkg.org

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