Re: Interacting with coherent memory on external devices

[Christoph Lameter]

On Wed, 22 Apr 2015, Paul E. McKenney wrote:

> Agreed, the use case that Jerome is thinking of differs from yours.
> You would not (and should not) tolerate things like page faults because
> it would destroy your worst-case response times.  I believe that Jerome
> is more interested in throughput with minimal change to existing code.

As far as I know Jerome is talkeing about HPC loads and high performance
GPU processing. This is the same use case.

> Let's suppose that you and Jerome were using GPGPU hardware that had
> 32,768 hardware threads.  You would want very close to 100% of the full
> throughput out of the hardware with pretty much zero unnecessary latency.
> In contrast, Jerome might be OK with (say) 20,000 threads worth of
> throughput with the occasional latency hiccup.
>
> And yes, support for both use cases is needed.

What you are proposing for High Performacne Computing is reducing the
performance these guys trying to get. You cannot sell someone a Volkswagen
if he needs the Ferrari.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/