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--- cluster:182 [2019/08/12 16:48]
hmeij07 [Lammps]
+++ cluster:182 [2019/08/12 17:40]
hmeij07 [Gromacs]
@@ Line 72: / Line 72: @@
 Precision for GPU calculations
-  * DD -D_DOUBLE_DOUBLE  # Double precision for all calculations
+  * [DD] -D_DOUBLE_DOUBLE  # Double precision for all calculations
-  * SD -D_SINGLE_DOUBLE  # Accumulation of forces, etc. in double
+  * [SD] -D_SINGLE_DOUBLE  # Accumulation of forces, etc. in double
-  * SS -D_SINGLE_SINGLE  # Single precision for all calculations
+  * [SS] -D_SINGLE_SINGLE  # Single precision for all calculations
@@ Line 82: / Line 81: @@
 |  SD  |  981,897|  ?|  916,225|  881,247|  2,294,344|  |
 |  SS  |  1,050,796|  ?|  1,035,041|  1,021,477|  2,541,435|  |
+As with Amber, it is best to run one job per GPU to achieve max node performance. Depending on problem set performance can be boosted by requesting more MPI threads. In previous tests the P100 in double_double precision mode achieved 2.7 million tau/day, so these results are surprising. The RTX 6000 does a decent job of keeping up with the P100.
+But the T4 shines in this application. The mixed or single precision modes compete well given the T4's price and  wattage consumption.
+==== Gromacs ====
+Gromacs was build on each of the nodes locally letting it select the optimal CPU (AVX, SSE) and GPU accelerators. The ''cmake'' flag -DGMX_BUILD_OWN_FFTW=ON yields a mixed precision compilation which is recommended. The we ran multidir options 01-04 on single GPU, and 01-08 and 01-16 on all 4 GPUs when possible.
+^  ns/day  ^  P100[1]  ^  P100[4]  ^  RTX[1]  ^  T4[1]  ^  T4[4]  ^  Notes  ^
+|  Mixed  |  |  |  254|  |  |  gpu=1, 01-04  |
+|  Mixed  |  |  551|  |  |  546|  gpu=4, 01-04  |
+|  Mixed  |  |  |  |  |  650|  gpu=4, 01-08  |
+|  Mixed  |  |  |  |  |  733|  gpu=4, 01-16  |
 ==== Scripts ====

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