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TuxCare BlogeBPF for Advanced Linux Performance Monitoring and Security
by Rohan Timalsina
March 4, 2025 - TuxCare expert team
Monitoring Linux performance and security isn’t easy, and traditional tools often miss critical details. eBPF (extended Berkeley Packet Filter) is changing that, enabling administrators to track system calls, network activity, CPU usage, and more — all with minimal overhead. In this article, we’ll explain how eBPF works, what it’s used for in various real-world applications, and which tools make it accessible.
What Is eBPF?
eBPF, or Extended Berkeley Packet Filter, is a new technology that allows safe and efficient execution of user-defined programs in the Linux kernel. Unlike traditional approaches that rely on incomplete sampling or kernel modules, in eBPF, all that is possible without directly modifying the kernel source or loading kernel modules. Initially developed for packet filtering, eBPF is highly evolved now, thus being an incredibly complete framework for monitoring, security, and performance enhancement.
How Does eBPF Work?
eBPF collects and processes data through attach points within the kernel (and sometimes user-space applications), storing the results in maps accessible from user-space. There is an inbuilt verifier that makes it very difficult for eBPF programs to crash the kernel due to bugs in their logic. Think of it as a small virtual machine attached to key system events — from network traffic and system calls to function executions — without adding a latency burden on those things.
The Evolution from BPF to eBPF
The origin of the eBPF story dates back to Berkeley Packet Filter (BPF) in 1992. BPF was meant to filter network packets efficiently and safely within the kernel. Developers could write programs in a restricted C-like language, and BPF would then compile bytecode for kernel execution.
Over a period, BPF has proven useful beyond packet filtering. Nonetheless, it had its limitations due to its original design. It had limited instruction sets and essentially catered for network operations. This realization prompted significant extensions to overcome these constraints and gain functionality beyond what earlier BPF could perform, leading ultimately to what we now call extended BPF (eBPF).
With the introduction of eBPF in Linux kernel versions, the functionality expanded dramatically. The instruction set is extended, making it much more versatile and allowing it to be used for a much wider range of purposes than packet filtering.
In addition, it is critically important that the eBPF programs run in a sandboxed environment in the kernel, which prevents them from crashing the kernel while still enforcing that protection through a verifier, which checks the programs before they load. Maps were also introduced by eBPF; these are data structures that allow eBPF programs to communicate with user space applications. These advancements transformed BPF from a simple packet filter into a general-purpose framework for kernel instrumentation.
Use Cases of eBPF
Since its introduction, eBPF has seen widespread adoption across various domains:
Network Observability: It provides deep insights into network behavior that includes packet inspection, performance tuning, and advanced network monitoring without the overhead of traditional methods. For example, eBPF can be applied to analyze TCP retransmits, network latency measurements, and custom load balancing.Performance Monitoring and Observability: Using eBPF, system administrators can obtain detailed performance metrics and trace events in the kernel and even user-space applications. This helps enhance application performance and system reliability with real-time visibility into complex systems. Tools such as Cilium and Falco leverage eBPF to provide enhanced observability and security for Kubernetes and cloud-native environments. It can help identify CPU hotspots, analyze disk I/O, and trace system calls to highlight performance bottlenecks.
Security Enhancements: Security programs make use of eBPF to build systems for intrusion detection, filtering system calls, and runtime security enforcement. By restricting the capabilities of potentially malicious software at the kernel level, it increases overall system security. For instance, eBPF can monitor execve calls for suspicious commands, or track file access to detect unauthorized modifications.
eBPF for Performance Monitoring
The ability to attach to various kernel and user-space events, coupled with efficient data collection and analysis, makes eBPF a powerful technology for performance monitoring. Let’s explore some key use cases:
Tracing System Calls
System calls define interfaces between applications and the kernel. By attaching kprobes to system calls such as read, write, open, close, execve, etc., eBPF can give deep insights into application behavior. Latency measurements for these system calls can be used to help locate I/O bottlenecks; measuring bytes read or written can be useful for understanding data throughput; and tracing system call arguments allows one to understand application behavior in depth. For example, using eBPF to trace the read and write system calls associated with disk access can pinpoint why a database query is running slow.
Profiling CPU Usage
Identifying CPU hotspots is important for performance optimization of applications. eBPF can utilize perf_events to make such profiling possible for kernel and user-space code. You can use perf_event to trigger eBPF programs on CPU events like cache misses or branch mispredictions, allowing you to precisely ascertain performance bottlenecks at a granular level. Uprobes, on the other hand, are used to profile user-space application functions to identify performance hotspots within application code. This can be helpful for optimizing critical code paths or uncovering inefficient algorithms.
Network Performance Monitoring
Network performance is important to many applications. eBPF can monitor network packets and socket activities as they happen. You can track TCP retransmits, measure connection establishment times, analyze packet loss, or inspect packet headers to understand traffic patterns with eBPF programs. For example, you could write an eBPF program to identify an excessive amount of TCP retransmits, helping you to diagnose network congestion or faulty network hardware.
Disk I/O Analysis
Slow disk I/O can adversely impact application performance. Disk read and write activities can be tracked through eBPF monitoring, which gives detailed insights into disk latency, throughput, and I/O patterns. With this, you can also spot I/O-bound applications, slow storage devices, and types of I/O operations being performed. An example would be writing an eBPF program to pinpoint which processes are causing the most disk I/O, which should help with optimizing storage usage or identifying applications that would benefit from faster storage.
Real-time Metrics and Dashboards
You can use tools like Prometheus and Grafana to aggregate and visualize the data collected by eBPG programs. This enables you to create real-time dashboards that show a comprehensive picture of your system performance. You can collect custom metrics and use Prometheus to store and query that data. Grafana can then be used to create visually appealing dashboards for easy monitoring of your system’s performance and detection of potential issues.
Companies like Netflix, Facebook, and Cloudflare use eBPF to diagnose performance issues, optimize their infrastructure, and gain deeper insights into their systems. For example, Netflix uses it for network performance analysis and to identify bottlenecks in their content delivery network, while Facebook uses it to monitor the performance of their databases and identify slow queries.
eBPF for Security Enhancement
Beyond its applications for performance monitoring, eBPF has become an important technology in security. Its ability to inspect system behavior in detail and execute programs within the kernel makes it well-suited for building fundamental security solutions.
System Call Auditing
System calls are the interface through which applications interact with the kernel. By monitoring system calls with eBPF, you can closely track application behavior and detect unauthorized events. For example, it can track execve calls to monitor command executions or open calls to detect access to sensitive files. It allows the creation of sophisticated auditing systems to inform of possible malicious activity in real time, such as attempts by a process to escalate privileges or access restricted resources.
Network Security
With eBPF, it is possible to build powerful network intrusion detection and prevention systems (NIDS/NIPS). As eBPF programs can be attached to network packets, they allow real-time analysis without the overhead of traditional packet filtering techniques. Malicious network activities, such as port scans, denial-of-service attacks, or communication with malware, could be detected, and packets could be dropped or modified to mitigate the threat. For example, an eBPF program could detect and block traffic to and from known malicious IP addresses or track patterns consistent with a DDoS attack, such as high volumes of SYN packets or ICMP floods.
Container Security
While containers have revolutionized application deployment, containerization has also led to a number of new security challenges. eBPF is becoming increasingly essential for securing containerized environments. By monitoring system calls and network activity inside containers, you can start enforcing your container isolation policies to prevent security breaches. For instance, you can use eBPF to allow a container to make only certain system calls, thereby restricting its attack surface. Additionally, you can monitor network traffic to ensure that your containers only communicate with authorized entities.
File Integrity Monitoring
Detecting unauthorized modifications to critical files is essential for maintaining system integrity. It can be used to track file changes and alert you whenever suspicious activity may occur. For example, you could write an eBPF program to keep track of the changes made on the configuration files or system binaries to detect potential intrusions or malware infections.
Runtime Security Enforcement
It provides a mechanism for runtime security enforcement since it can intercept and modify system calls. eBPF programs can be used to prevent malicious behavior by blocking or modifying system calls, prior to being executed. For example, it can prevent a process from accessing a sensitive file, or restrict the arguments that can be passed in a particular system call.
Final Thoughts
eBPF is changing the way we monitor and secure Linux systems by enabling real-time observability with minimal overhead. From identifying performance bottlenecks to enforcing security policies, it provides a powerful and efficient approach. As enterprise adoption grows, eBPF will play an even greater role in system observability and threat detection.
But monitoring is only half the battle — keeping the Linux kernel secure is equally critical. Timely patching of the kernel is necessary to mitigate vulnerabilities, but traditional updates often require downtime. TuxCare’s KernelCare Enterprise eliminates this issue with live patching, allowing you to apply security fixes to the Linux kernel without reboots or service interruptions. KernelCare supports all major enterprise Linux distributions, including CentOS, RHEL, AlmaLinux, Rocky Linux, Ubuntu, Amazon Linux, and Oracle Linux.
