[HPGMG Forum] hydra IMC
mfadams at lbl.gov
Tue Jun 10 20:06:05 UTC 2014
I guess there is no MCB data. I've heard mention if the importance of
radiation and neutron transport codes.
It looks like UMT 2013 is a transport code and HPGMG matches it pretty well
with this data. For what that is worth.
On Tue, Jun 10, 2014 at 3:12 PM, Karlin, Ian <karlin1 at llnl.gov> wrote:
> Hi Mark,
> I'm adding Steve Langer the first author of the paper in case he has
> anything to add as he's been more focused on trying to track down latency
> Our results point to, but do not defiantly show the latency is the
> likely culprit for both the IMC and Laser packages. This is due to the low
> IPC, low BW utilization and high number of L2 misses per line fetched from
> memory. A number above 1 means that multiple reads occurred to a line in
> quick succession, but it was not prefetched. Below 1 means that many lines
> were successfully prefetched. We need to either look on other systems with
> better latency measurement capabilities or find the needle in a haystack
> (or combination thereof) of performance counters that gets us more
> definitive latency data.
> Note MCB does something, but not a lot more than IMC in Hydra. Likely
> this due to a smaller problem size that is run for MCB it has a higher
> cache hit rate so latency is not as large of a factor though MCB is often
> latency bound. We didn't think too hard about MCB though for this work.
> So to answer your question. Yes there are other metrics worth thinking
> about and latency is one of them. We're not sure how to capture all of
> them well, which is why we left the data off the kivet plots, but included
> hydra imc to show that we were missing something.
> From: Mark Adams <mfadams at lbl.gov>
> Date: Tuesday, June 10, 2014 8:32 AM
> To: WCI LLNL <karlin1 at llnl.gov>
> Cc: Theodore Omtzigt <theo at stillwater-sc.com>, HPGMG Forum <
> hpgmg-forum at hpgmg.org>, "Still, Bert" <still1 at llnl.gov>
> Subject: hydra IMC
> I see you are an author on a paper about Hydra (IMC). In our modeling
> efforts we are concerned about MC, transport, etc. that might be poorly
> represented with HPGMG. I would imagine that these methods use lots of
> streaming data but 'Hydra IMC' data on the spreadsheet does NOTHING! Do
> you have any thoughts on this? Is there a metric that you are not
> measuring here that should be and that we should think about?
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the HPGMG-Forum