Performance & Stability Optimizations

Performance & Stability Optimizations

This page documents the specific kernel and hardware tweaks applied to Terra (Ryzen 5950X / Ubuntu 24.04) to optimize for container performance, storage throughput, and long-term stability.

🛡️ Stability & Power Management (The "Golden Config")

Typical Current Idle (UEFI)

• Setting: Advanced > AMD CBS > CPU Common > Power Supply Idle Control = "Typical Current Idle"
• Benefit: Prevents the Ryzen "Sleep of Death" where the PSU cuts power during deep C-state transitions. Essential for 24/7 server stability on X570 boards.

Processor C-State Limit (Kernel)

• Driver: processor.max_cstate=1
• Benefit: Software-side enforcement of the Idle fix. Limits the CPU to C1 (Halt/Idle) instead of deeper sleep states (C6), preventing interrupt processing delays and hardware hangs.
• Configuration: Added to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub.

65W Eco Mode (Manual PBO)

• Settings: PPT: 88, TDC: 60, EDC: 90
• Benefit: Drastically reduces thermals (peak temps dropped from ~90°C to 58°C) without significant impact on multi-core performance. Ideal for 4U rackmount chassis airflow.
• Configuration: UEFI > Precision Boost Overdrive > Manual.

⚡ CPU & Power Performance

AMD P-State (Active Mode)

• Driver: amd_pstate=active (EPP - Energy Performance Preference)
• Benefit: Allows the kernel to communicate directly with the Zen 3 power management controller. Enables a wider frequency range (550MHz - 5000MHz).

IRQ Balancing

• Service: irqbalance (Installed/Enabled)
• Benefit: Distributes hardware interrupts (HBA, NVMe, NIC) across all threads, preventing Core 0 bottlenecks.

🧠 Memory Tuning

Speed & Stability

• Configuration: Currently hard-coded to 2133MHz at AUTO voltage.
• Note: Troubleshooting in Feb 2026 confirmed that 3000MHz at 1.35V caused instantaneous reboots. Stability requires sticking to JEDEC defaults for now.

Static Hugepages

• Setting: hugepages=2048 (Reserving 4GB total as 2MB pages)
• Benefit: Reduces TLB misses for memory-heavy apps like Minecraft and Postgres.

💾 I/O & Network Tuning (sysctl)

ZFS Write Buffering

• Settings: vm.dirty_background_bytes = 268435456, vm.dirty_bytes = 1073741824
• Benefit: Prevents the kernel from buffering too much data in RAM before flushing to ZFS, eliminating system-wide UI/process stutter.

Fluent-bit Batching (ClickHouse)

• Setting: Flush 60 in fluent-bit.conf
• Benefit: Reduced ClickHouse CPU usage from 80% spikes to <5% by reducing transaction frequency and optimizing ZFS write contiguousness.

🎮 GPU Optimization (Quadro P2200)

Persistence Mode

• Command: sudo nvidia-smi -pm 1
• Benefit: Eliminates the 2-second initialization delay for AI inference and transcoding containers.