Messages in this thread | | | Date | Tue, 01 Jun 2010 08:40:46 +0200 | From | Andi Kleen <> | Subject | Re: [dm-devel] [PATCH] DM-CRYPT: Scale to multiple CPUs |
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, Mikulas Patocka wrote: > Questions: > > If you are optimizing it, > > 1) why don't you optimize it in such a way that if one CPU submits > requests, the crypto work is spread among all the CPUs? Currently it > spreads the work only if different CPUs submit it.
This case is only useful with very slow CPUs and is handled by pcrypt in theory
(but I haven't tested it)
> > 2) why not optimize software async crypto daemon (crypt/cryptd.c) instead > of dm-crypt, so that all kernel subsystems can actually take advantage of > those multi-CPU optimizations, not just dm-crypt?
Normally most subsystems are multi-CPU already, unless they limit themselves artitifically like dm-crypt.
For dm-crypt would be wasteful to funnel everything through two single CPU threads just to spread it out again. That is why I also used per CPU IO threads too.
-Andi
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