The following patches can be applied according to RHE's CVE:



In order to quantify the impact of the Spectre / Meltdown fixes a number of tests have been run. Unless otherwise stated all results are from the Fidis cluster.

If all the recommended fixes are applied then we see a large impact on IO.  As computational kernels do not require frequent calls to the operating system the impact is far less significant.


GPFS IO Performance


IOR API=POSIX

IOR API=MPIIO

Comments

Impact is a loss of about 50% aggregate bandwidth when running IOR with one MPI task-per-node. 

Impact is much less visible when running IOR with 16 MPI tasks-per-node. 

Impact of 'Page Table Isolation (pti)' fix only

Situation of Fidis compute nodes after maintenance of January 24th, 2018:


Application Performance

MiniFE

Total running time in seconds on Fidis (lower is better)

nodes

size

before

after

41000x500x60034.936833.9214
21000x500x60067.213267.2067


Gear

Large test case. Steps per unit of time (higher is better)

nodes

before

after

10.2259320.224453
20.3977460.395822
40.626741

0.622084


CPMD

Average time per iteration in seconds (lower is better)

nodes

before

after

13.498353.53886
26.139756.20212
43.182663.22177

SPEC benchmark (CPU FP SPEED)


SPEC points (higher is better)

BeforeAfter
67.966.6


Quantum Espresso

espresso: version: 6.2.0
arch: platform: linux
platform_os: rhel7
target: x86_E5v4_Mellanox
compiler:
name: intel
version: 17.0.2
namespace: builtin
parameters:
elpa: true
hdf5: false
mpi: true
openmp: false
scalapack: true


BeforeAfter
1m22.35s CPU 1m27.18s WALL1m26.21s CPU 1m37.75s WALL