They have been supported with Arch x86-64, AArch64, S390x, PowerPC 64, and SPARC64.įor more information, look at these Linux kernel files: So far, support of kprobes, tracepoints, and perf_events filtering using eBPF have been implemented in the upstream kernel. Traditional built-in tracers in Linux are used in a post-process manner, where they dump fixed-event details, then userspace tools like perf or trace-cmd can post processes to get required information (e.g., perf stat) however, eBPF can prepare user information in kernel context and transfer only needed information to user space. eBPF and tracing review Upstream kernel development
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eBPF has been designed to be JIT'ed with one-to-one mapping, so it can generate very optimized code that performs as fast as natively compiled code. Further, an eBPF program can be written in C-like functions, which can be compiled using a GNU Compiler Collection (GCC)/LLVM compiler. Therefore eBPF can also be used for aggregating statistics of events. It also includes a global data store called maps, and this maps state persists between events. Whereas BPF has forward jumps, eBPF has both backwards and forwards jumps, so there can be a loop, which, of course, the kernel ensures terminates properly. eBPF machineĮxtended BPF (eBPF) is an enhancement over BPF (which is now called cBPF, which stands for classical BPF) with more resources, such as 10 registers and 1-8 byte load/store instructions. Such a compiler exists for x86-64, SPARC, PowerPC, ARM, ARM64, MIPS, and System 390 and can be enabled through CONFIG_BPF_JIT. This compiler translates BPF bytecode into a host system's assembly code. BPF just-in-time compilerĪ just-in-time (JIT) compiler was introduced into the kernel in 2011 to speed up BPF bytecode execution. If it is not an IP packet, 0 will be returned, and the packet will be rejected. The ldh instruction loads a half-word (16-bit) value in the accumulator from offset 12 in the Ethernet packet, which is an Ethernet-type field. It provides a secure, simple, and efficient means of understanding what is happening within all Linux-based endpoints. In this way, eBPF helps address one of the core challenges of network observability in modern applications. It also provides access to low-level networking data that may not be available from within a container, whose access to kernel-level resources is usually restricted (unless the container runs in privileged mode, which is not a recommended approach). In this way, eBPF eliminates the need to deploy agents for each container separately. With eBPF, teams can run kernel-level programs that observe network operations for all containers running on a server. To address these challenges, teams had to deploy a complex array of userland applications-often, a network monitoring agent on each server, as well as an agent that could collect networking data from each container through a service mesh, sidecar architecture or similar approach.ĮBPF offers a much simpler, more elegant solution to network observability. What’s more, it requires getting network data from individual containers that, in most cases, don’t log their networking operations to their host operating system, or even store network-related data persistently. Under these conditions, observing the network has conventionally required collecting and correlating data about network operations from a variety of servers. They are also frequently hosted inside containers, serverless functions or similar types of infrastructure, which abstracts applications from the host operating system. Modern applications are often deployed across a cluster of servers. However, one of the areas where eBPF offers the very most value is in the realm of network observability. EBPF has many potential use cases related to observability, such as monitoring the performance of hardware devices or helping to detect security issues.
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