Performance degradation notes for Intel Optane DC Persistent Memory Module with Memory Mode configuration

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 7.6
  • Red Hat Enterprise Linux 8.0
  • Intel Optane DC Persistent Memory Module (DCPMM) with Memory Mode configuration

Issue

  • When DCPMM is configured for the Memory Mode, the system may encounter performance degradation even with sufficient DRAM cache available.
  • The performance degradation is notable with the tiered memory configuration and heavy memory workloads, when applications hit large percentages of memory occasionally.
  • The slowdown under the heavy memory stress loads can result in the soft and hard lockups and under severe memory pressure hard lockups in the kernel can result in a panic.

Resolution

  • Although Red Hat supports DCPMM with Memory Mode configuration, the replacement of the DCPMM with standard DRAM for the system memory or increasing the amount of DRAM for the cache may be required in order to resolve the soft and hard lockup problems.
  • The proof of concept validation is highly recommended in prior, to ensure the configuration satisfies your applications’ requirements.
  • Please consult your hardware vendor for further guidance.

Root Cause

  • DCPMM with Memory Mode has both lower memory bandwidth and higher latency than standard DIMM memory.

This solution is part of Red Hat’s fast-track publication program, providing a huge library of solutions that Red Hat engineers have created while supporting our customers. To give you the knowledge you need the instant it becomes available, these articles may be presented in a raw and unedited form.

Comments