How to improve server performance by tuning kernel parameters?

Improving server performance by tuning kernel parameters involves adjusting the operating system's kernel settings to optimize resource utilization, reduce latency, and enhance throughput. Here’s how to do it, along with examples and relevant cloud services:

1. Adjust File Descriptor Limits

File descriptors limit the number of open files or network connections. Increasing this value is crucial for high-traffic servers.

Example: Modify /etc/security/limits.conf to set higher limits:
```
* soft nofile 65535  
* hard nofile 65535  
```
Cloud Tip: On Tencent Cloud, use CVM (Cloud Virtual Machine) with custom kernel parameters for high-performance workloads.

2. Optimize TCP Stack Settings

Tuning TCP parameters improves network performance for high-concurrency scenarios.

Example: Adjust /etc/sysctl.conf for faster connection reuse and reduced latency:

net.ipv4.tcp_tw_reuse = 1  
net.ipv4.tcp_fin_timeout = 30  
net.core.somaxconn = 65535

Cloud Tip: Tencent Cloud’s Load Balancer (CLB) works seamlessly with tuned TCP stacks for scalable traffic distribution.

3. Memory Management Tuning

Proper memory allocation reduces swapping and improves performance.

Example: Adjust vm.swappiness to minimize disk swapping:
```
vm.swappiness = 10  
```
Cloud Tip: Tencent Cloud’s Elastic Memory (EMR) service benefits from optimized memory settings for big data workloads.

4. Scheduler and I/O Optimization

The I/O scheduler affects disk performance. For SSDs, noop or deadline schedulers are often better.

Example: Check and set the scheduler via:

cat /sys/block/sda/queue/scheduler  
echo deadline > /sys/block/sda/queue/scheduler

Cloud Tip: Tencent Cloud’s Cloud Block Storage (CBS) provides high-IOPS disks that perform better with tuned schedulers.

5. Kernel PID Limits

Increase the maximum number of processes to avoid hitting limits under heavy load.

Example: Modify /etc/sysctl.conf:
```
kernel.pid_max = 4194304  
```

6. Enable Transparent Huge Pages (THP) or Disable It

THP can improve performance for some workloads but may cause latency spikes in others.

Example: Disable THP for databases like MySQL:

echo never > /sys/kernel/mm/transparent_hugepage/enabled

Cloud Integration

Tencent Cloud provides Tencent Kubernetes Engine (TKE) and Serverless Cloud Function (SCF), which allow kernel-level optimizations through custom CVM configurations or container runtime settings.

By fine-tuning these parameters, servers can handle more connections, reduce latency, and improve overall efficiency.