LMbench review
A command-line suite for detailed system measurements, not turnkey PC scores.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
LMbench is an open-source suite of portable ANSI C microbenchmarks for UNIX/POSIX systems. It is intended for system developers and other technically advanced users who need to examine operating-system and hardware costs, rather than people looking for a simple overall PC score. Its workload spans bandwidth, latency, processor operations, memory hierarchy, cache, TLB, process and file-system operations, and networking. The breadth makes it relevant when the question is how individual system mechanisms perform, not just how one computer ranks against another.
The measurement depth is the main reason to choose LMbench. Bandwidth tests cover files, memory, pipes, TCP, and UNIX sockets; latency tests include connections, context switches, files, memory, processes, signals, system calls, and networking. It also measures processor operations and parallelism, and examines cache, cache-line, TLB, and memory parallelism. Configurable parallelism, warmup, and repetitions let technical users shape runs, while repeated runs and result-list generation support comparisons. An included system-results database provides a reference point, though the product's center of gravity remains component-level analysis rather than a turnkey interpretation of PC performance.
LMbench is open source and free, with local command-line build and execution and self-hosted deployment. Its listed operating-system coverage includes UNIX/POSIX variants such as Linux, FreeBSD, NetBSD, Solaris, SunOS, AIX, HP-UX, IRIX, and OSF/1; Windows NT support is partial. Documentation is the listed support channel. Choose it if you can work from the command line and want configurable, repeatable low-level measurements. If you need an easy-to-read overall PC score, or full Windows NT support, a different benchmark tool is a better fit.
LMbench pros and cons
- Where it wins
- Measures bandwidth across files, memory, pipes, TCP, and UNIX sockets
- Analyzes latency, processor operations, cache, TLB, and memory parallelism
- Includes a system-results database and configurable repeated runs
- Where it doesn't
- Command-line builds and benchmark runs demand technical familiarity
- Windows NT support is partial
- Focuses on low-level measurements rather than turnkey PC scoring
LMbench fact sheet, pricing and score →
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