High Performance Computing

ANSYS Desktop HPC – Release 18

• All workstations can utilize HPC – even laptops.

• Modern CPU’s have 4 cores minimum

• Performance depends on model size relative to all available hardware

Why Desktop HPC?

Advantages

• Make use of workstation hardware

• No need to maintain a cluster or server

• Increase the size and amount of detail in models

• Increase simulation throughput to enhance productivity.

• Improved labour costs.

Hardware Requirements:

HPC

RAM

Hard-drive

CPU

Hardware Explanation

• Short-term memory

• Size required is model dependant

• Frequency Counts – Higher is better

RAM

• Longer-term memory

• Speed (SSDs are recommended)

• Can have separate disk for working directory and for longer-term storage options

Hard-drive• The number cruncher

• Number of cores – More is better

• ‘Clock’ speed – Higher is better

CPU

Using RAM or Hard-Drive

IN-CORE IS FASTER

Runs the solution with the entire factorized matrix in RAM – ideal!

OUT-OF-CORE IS SLOWER

Stores the entire factorized matrix on hard-disk, resulting in sub-optimal performance

• Having enough RAM to enable an IN-CORE solution is highly recommended.

• RAM is typically an order of magnitude quicker than even a ‘fast’ hard-drive.

• Solve times for structural simulation can be reduced five-fold by increasing RAM.

Not enough RAM, sad!

ANSYS HPC

Mechanical:

Two cores by default

Choice of SMP or DMP solver modes

DMP uses more RAM but solver scaling is superior at higher core counts

Fluids:

Single core by default at R17*

Parallel mode requires an HPC license.

The host thread in Parallel simulations doesn’t count towards HPC license usage

*Now 4 cores at R18 for all CFD Premium & Enterprise customers.

SMP & DMP Explained

Shared Memory Parallel (SMP)• Cores work together asynchronously.

• RAM usage stays the same regardless of the number of cores allocated.

• Can lead to ‘race conditions’ where cores compete for resources, which can be problematic at higher core counts.

Distributed Memory Parallel (DMP)• Each core works on an allocation of the solution domain.

• Information is passed using a Message Passing Interface.

• For a given model size, memory requirements increases relative to the number of cores allocated.

• Scales better than SMP…

NOTE:In ANSYS Workbench (Mechanical) the default memory setting is now DMP –this has been the case since ANSYS R17.

Previous releases had SMP set as default option.

SMP vs DMP: ANSYS Mechanical

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2 4 6

RA

M

Solv

er

Rat

ing

Core Count

DMP RAM

SMP RAM

DMP Solver Rating

SMP Solver Rating

• DMP solver rating is the best at higher core counts.

• DMP memory (RAM) requirements increase with higher core counts.

• Both methods enable significant reductions in elapsed simulation times.

Fluids HPC: Serial vs Parallel

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

2.0 3.0 4.0 5.0 6.0 7.0 8.0

Solv

er

Rat

ing

Core Count

Solver Rating (vs Serial)

Solver Rating (vs 2-Core)

Eight cores in Parallel: More than 9 times faster than Serial.Two cores in Parallel:

Almost 3 times faster than Serial!

Eight cores in Parallel: More than 3 times faster than two core Parallel.

HPC Licensing Options

1. HPC (per-process)

2. HPC Pack• HPC product rewarding volume parallel processing for high-

fidelity simulations

• Each simulation consumes one or more Packs

• Parallel enabled increases quickly with added Packs

3. HPC Workgroup• HPC product rewards volume parallel processing for increased

simulation throughput shared among engineers throughout a single location or the world

• 16 to 32768 parallel shared across any number of simulations on a single server

4. HPC Parametric Pack• Enables simultaneous execution of multiple design points while

consuming just one set of licenses

2048

32

8

128

512

Parallel

Enabled

(Cores)

HPC Packs per Simulation

1 2 3 4 5

32768

8192

6 7

Single HPC solution for FEA/CFD/FSI and any level of fidelity

10 instead of 8 in 1st Packat Release 18.0 and higher

For Further Information & Benchmarks

Contact us:

+44 (0)161 4746886

info@WildeAnalysis.co.uk

http://WildeAnalysis.co.uk

ANSYS Benchmarks:

http://www.ansys.com/Solutions/Solutions-

by-Role/it-professionals/platform-

support/benchmarks-overview