PowerEdge XE9685L: Expected PCIe bandwidth contention under concurrent stress testing
Summary: On PowerEdge XE9685L platforms, PCIe bandwidth contention can occur among devices behind a common PCIe switch. Devices include GPUs, NICs, and NVMe devices, where multiple high-throughput workloads may saturate the shared upstream uplink to the CPU/root complex. This saturation results in reduced performance. ...
This article applies to
This article does not apply to
This article is not tied to any specific product.
Not all product versions are identified in this article.
Symptoms
- Lower than expected network and/or GPU performance.
- Packet drops observed during high network throughput tests.
- Typically reproducible only under synthetic or stress-test conditions, or under production workload conditions that maximize GPU and Network throughput.
Cause
This occurs when simultaneous high-throughput traffic from multiple devices sharing PCIe architecture compete for shared upstream PCIe paths.
PCIe Gen5 x16 provides a theoretical maximum throughput of 64 GB/s per direction, though actual bandwidth is typically less.
Resolution
This is working as designed and is consistent with architectural limitations under stress conditions.
Affected Products
PowerEdge XE9685LArticle Properties
Article Number: 000464395
Article Type: Solution
Last Modified: 22 محرم 1448
Version: 3
Find answers to your questions from other Dell users
Support Services
Check if your device is covered by Support Services.