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cluster:175 [2018/09/25 12:39] hmeij07 [Lammps] |
cluster:175 [2018/09/26 20:11] hmeij07 [Gromacs 2018.3] |
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</ | </ | ||
- | == Lammps (PMMA) == | + | ==== Lammps (PMMA) |
- | Material | + | Using a material |
- | + | ||
- | a) 1GPU with X CPUs | + | |
- | #cpus | + | ^ gpu ^ |
- | 4 | + | | |
- | 2 | + | | |
- | 1 | + | | |
- | + | ||
- | b) 4 GPUs with 4 CPUs | + | |
- | 92 ns/day | + | |
- | + | ||
- | ---------- | + | |
- | compare these results to | + | |
- | + | ||
- | 1 K20 GPU + 4 CPUs 37 ns/day | + | |
- | 1 K20 GPU + 6 CPUs 47 ns/day | + | |
- | 1 GTX GPU + 4 CPUs 73 ns/day | + | |
- | 1 GTX GPU + 6 CPUs 90 ns/day | + | |
+ | That means the P100 works as well as the GTX. The K20 works at 50% the performance level of the others which is impressive for this old gpu. | ||
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</ | </ | ||
+ | |||
+ | ==== Gromacs 2018.3 ==== | ||
+ | |||
+ | The multidir not running in Gromacs 2018 is a bug in the code clashing with the call MPI_Barrier (communication timing error). | ||
+ | |||
+ | < | ||
+ | |||
+ | # multidir -gpu_id 0123 with four simultaneous gromacs processes | ||
+ | |||
+ | -np 8 -ntomp | ||
+ | 01/ | ||
+ | 02/ | ||
+ | 03/ | ||
+ | 04/ | ||
+ | |||
+ | -np 16 -ntomp | ||
+ | 01/ | ||
+ | 02/ | ||
+ | 03/ | ||
+ | 04/ | ||
+ | |||
+ | multidir -gpu_id 00112233 with eight simultaneous gromacs processes | ||
+ | sharing the gpus, 2 processes per gpu | ||
+ | |||
+ | -np 8 -ntomp | ||
+ | Error in user input: | ||
+ | The string of available GPU device IDs ' | ||
+ | device IDs | ||
+ | |||
+ | </ | ||
+ | |||
+ | That last error when loading multiple processes per gpu is *not* according to their documentation. So the multidir performance is similar to previous single dir performance but still lags GTX performance by quite a bit. Albeit, there is room in utilization rate of the gpus. | ||
+ | |||
==== What to Buy ==== | ==== What to Buy ==== |