[dm-devel] cmwq and dm-crypt devices?
Andi Kleen
andi at firstfloor.org
Wed Nov 3 11:51:44 UTC 2010
>
> > 2) scale up the number of workqueue threads used for a single dm-crypt
> > device so that a device can realize per-cpu concurrency (to address
> > Andi's scalability concerns: https://patchwork.kernel.org/patch/244031/)
They are already addressed in my patchkit and the patches seem to be used
by more and more users. It's just you guys who are behind.
> >
> > [the desired locality is currently missing due to dm-crypt's current
> > use of WQ_UNBOUND; so it is clear the way the workqueues are created
> > will be important]
>
> I don't know enough about dm-crypt workload to tell whether per-cpu
> affinity would be better or not, but it's really a simple matter of
CPU affinity and an own thread makes sense for the crypto helper
because it uses up a lot of CPU time.
For the IO helper you probably still want CPU affinity, but it
can be concurrency managed.
-andi
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