Messages in this thread | | | Subject | Re: Interacting with coherent memory on external devices | From | Benjamin Herrenschmidt <> | Date | Fri, 24 Apr 2015 08:29:57 +1000 |
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On Thu, 2015-04-23 at 09:10 -0500, Christoph Lameter wrote: > On Thu, 23 Apr 2015, Benjamin Herrenschmidt wrote: > > > > Anyone > > > wanting performance (and that is the prime reason to use a GPU) would > > > switch this off because the latencies are otherwise not controllable and > > > those may impact performance severely. There are typically multiple > > > parallel strands of executing that must execute with similar performance > > > in order to allow a data exchange at defined intervals. That is no longer > > > possible if you add variances that come with the "transparency" here. > > > > Stop trying to apply your unique usage model to the entire world :-) > > Much of the HPC apps that the world is using is severely impacted by what > you are proposing. Its the industries usage model not mine. That is why I > was asking about the use case. Does not seem to fit the industry you are > targeting. This is also the basic design principle that got GPUs to work > as fast as they do today. Introducing random memory latencies there will > kill much of the benefit of GPUs there too.
How would it be impacted ? You can still do dedicated allocations etc... if you want to do so. I think Jerome gave a pretty good explanation of the need for the usage model we are proposing, it's also coming from the industry ...
Ben.
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