本文总结了Broadcom关于vSphere 8性能调优的白皮书，重点介绍了如何通过优化虚拟化环境来降低延迟，以满足金融服务、媒体流和实时自动化等对延迟敏感的应用需求。文章提供了从硬件、ESXi主机、虚拟机到网络和操作系统层面的详细优化建议，以帮助用户构建更高效、响应更快的虚拟化基础设施。

⚙️ **硬件与软件基础**: 确保环境运行在最新的硬件和软件上，包括最新的CPU、更新的BIOS和微代码、vSphere 8.0 U3或7.0 U3及以上版本、Virtual Hardware 21或更新版本，以及VM Tools 12.4.5或更新版本。此外，尽量减少vSphere Overlay的使用，如NSX和vSAN，以避免增加CPU周期和潜在的延迟。

💻 **主机级别优化**: 在ESXi主机上进行关键配置，如将电源管理设置为“高性能”，禁用C状态和P状态，启用Turbo Boost。避免使用EVC，以防止CPU指令被屏蔽，从而降低延迟。同时，在高峰时段避免vMotion和DRS调度，并禁用action affinity，启用SplitRX和SplitTX以改进网络处理，以及禁用队列配对以防止网络瓶颈。

🖥️ **虚拟机级别优化**: 确保正确配置虚拟机，包括调整虚拟机大小以避免超出NUMA节点限制，禁用Hot-Add，设置高延迟敏感度，并为延迟敏感型虚拟机保留CPU和内存。配置VMXNET3网络适配器以获得最佳性能，并手动将虚拟机分配给NUMA节点以与底层硬件对齐。考虑使用SR-IOV或DirectPath I/O以实现超低延迟的网络连接。

🌐 **网络增强**: 针对网络密集型工作负载，推荐使用VMXNET3，以获得优化的性能。对于需要高吞吐量的NFV工作负载，启用增强的数据路径模式。考虑使用SmartNICs和DPUs来将网络处理卸载到专用硬件。调整NIC环形缓冲区大小并启用多个网络队列以实现队列平衡。

🐧 **操作系统和应用程序调优**: 在客户操作系统内，使用Photon OS实时内核，该内核针对低延迟应用程序进行了优化。配置NUMA感知应用程序以利用NUMA拓扑。通过将虚拟机工作负载分配给特定的CPU内核来防止争用，实现线程亲和性。

In today’s fast-paced digital world, low-latency computing is critical for applications in financial services, media streaming, and real-time automation. VMware vSphere 8 introduces a suite of performance enhancements designed to optimize virtualized environments for latency-sensitive workloads. This guide summarizes key takeaways from Broadcom’s latest whitepaper on performance tuning for vSphere 8.

Understanding Latency Optimization in vSphere 8

VMware vSphere 8 provides a powerful platform for virtualized workloads, balancing high performance with efficient resource utilization. However, for latency-sensitive applications, additional tuning is required to minimize response times. The key tradeoff here is increased CPU utilization in exchange for reduced latency.

Baseline Recommendations

To maximize performance for low-latency applications, it’s essential to ensure your environment is running the latest hardware and software:

Processor generations: Use the latest supported CPUs. BIOS and microcode: Ensure firmware is up to date. vSphere version: At least vSphere 8.0 U3 or 7.0 U3. Virtual Hardware Version: Use Virtual Hardware 21 or newer. VM Tools: Version 12.4.5 or newer.

Additionally, minimize the use of vSphere overlays like NSX and vSAN, as these services consume CPU cycles and may increase latency.

Host-Level Optimizations

Optimizing ESXi host configurations is crucial for reducing latency:

BIOS Settings: Set power management to "High Performance," disable C-states and P-states, and enable Turbo Boost. Disable EVC: Enhanced vMotion Compatibility (EVC) can mask CPU instructions and increase latency. vMotion and DRS Scheduling: Avoid live migrations during peak performance periods, as they can momentarily disrupt workloads. Advanced Settings:
Disable action affinity Enable SplitRX and SplitTX for improved network processing Disable queue pairing to prevent network bottlenecks

Virtual Machine-Level Optimizations

Configuring VMs correctly can significantly impact latency:

Rightsizing: Ensure VMs are not oversized beyond NUMA node limits. Disable Hot-Add: This prevents NUMA topology from being exposed, reducing performance. Set High Latency Sensitivity:
Reserve CPU and memory exclusively for latency-sensitive VMs. Configure VMXNET3 network adapters for optimal performance.
NUMA Awareness: Assign VMs to NUMA nodes manually to align with the underlying hardware. Use SR-IOV or DirectPath I/O: These features allow direct hardware access for ultra-low latency networking.

Networking Enhancements

For network-intensive workloads, consider:

VMXNET3: This paravirtualized NIC offers optimized performance. Enhanced Datapath Mode: For NFV workloads requiring high throughput. SmartNICs and DPUs: Offload network processing to dedicated hardware. Queue Balancing: Adjust NIC ring buffer sizes and enable multiple network queues.

Guest OS and Application Tuning

Within the guest operating system, use:

Photon OS Real-Time Kernel: Optimized for low-latency applications. NUMA-aware applications: Configure workloads to take advantage of NUMA topology. Thread Affinity: Assign VM workloads to specific CPU cores to prevent contention.

Operational Best Practices

Use esxtop and net-stats to monitor performance. Adjust ring buffers and queue sizes using esxcli. Test all changes in a non-production environment before deployment.

Conclusion

By following these best practices, VMware vSphere 8 can be fine-tuned to deliver low-latency performance for critical workloads. Whether optimizing host settings, configuring VMs, or leveraging SmartNICs, these strategies help ensure a responsive and efficient virtualized infrastructure.

For a more in-depth guide, refer to Broadcom’s whitepaper on performance tuning in vSphere 8.