Following on from the previous post concerning OpenFOAM benchmarks against spectre and meltdown fixes, the next set come from a Dell T1700 (E3-1270 v3, 16GB RAM) but this time we’ve looked at more applications, specifically:
- MATLAB 2017b
- CFD-ACE+ 2015
- ANSYS 18.2
The methodology for the tests was to run the benchmarks three or four times to get an average reading (with standard deviation) for three cases:
- Base system as it was;
- Fully patched system but with RedHat tuneables off, and;
- Fully patched system with RedHat tuneables on.
For refernce the base system was running Dell’s A19 BIOS and RedHat’s kernel 3.10.0-514.6.1.el7.x86_64. Whereas the final system was running A24 and 3.10.0-693.11.6.el7.x86_64, respectively. The results are all relative to the base case with the “Relative Difference” column computed as:
with the standard deviation column being a normalise sample standard deviation.
Interestingly, the results indicated that patching a very old BIOS may increase the performance of your code. For example, the MATLAB benchmarks ran faster across the board after applying both the BIOS patches and the OS patches.
Alternatively, both CFD-ACE+ and ANSYS, in general, saw a speed increase with the BIOS patches, as would be expected with the more efficient microcode updates in place, but then decreased after applying RedHat’s suggested mitigation tunables.
Again, the conclusion is that for these workloads there is relatively little hit for applying the BIOS and OS patches, especially if you are already running an older BIOS without modern microcode updates.
The full results are listed below.
First up were the MATLAB 2017B results, as shown in the table below.
| Base | BIOS Only | BIOS + Kernel | ||||
| Ref | STD Dev | Rel Diff | STD Dev | Rel Diff | STD Dev | |
| Matrix | 1 | 2.058% | 0.965 | 0.823% | 0.903 | 0.028% |
| FFT | 1 | 0.577% | 0.831 | 0.193% | 0.827 | 2.061% |
| Wavelet | 1 | 0.071% | 0.997 | 0.061% | 0.975 | 0.028% |
Followed with the CFD-ACE+ results, as listed below.
| Base | BIOS Only | BIOS + Kernel | ||||
| Ref | STD Dev | Rel Diff | STD Dev | Rel Diff | STD Dev | |
| VOF | 1 | 0.841% | 0.984 | 0.031% | 1.023 | 0.111% |
| Multi4 | 1 | 0.219% | 0.994 | 0.233% | 1.009 | 0.253% |
Finally the ANSYS 18.2 results, as listed below.
| Base | BIOS Only | BIOS + Kernel | ||||
| Ref | STD Dev | Rel Diff | STD Dev | Rel Diff | STD Dev | |
| Couple | 1 | 2.000% | 1.007 | 1.147% | 0.993 | 1.162% |
| V18sp-1 | 1 | 2.244% | 0.948 | 1.624% | 0.967 | 2.030% |
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