Exploring *BSDs: A Journey Beyond GNU/Linux Dominance
Join a research engineer as they share their experience transitioning from GNU/Linux to *BSDs like FreeBSD and OpenBSD. Discover their motivations, contributions to the *BSD community, and implementation of lscpu for *BSD environments.
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lscpu for *BSDs Xiao, Nan
Who AM I? A research engineer working in DSI. like researching techs related to computer infrastructure, such as Operating System kernel, concurrent programming, debugging, etc. Non-native English speaker, so please bear my poor oral English and grammar errors in both talk&slides.
Agenda Why *BSDs? lscpu for GNU/Linux. Implement lscpu for *BSDs. Takeaway
GNU/Linux dominates the world! Examples: The top 500 supercomputers all run GNU/Linux (please refer here): Although my previous employer (HPE) has its own Unix Operating System (HP-UX), it puts main focus on GNU/Linux. The same situation as Oracle/Solaris.
Why did I begin to use *BSDs? No special reasons, just tired of GNU/Linux is everywhere! It run on all servers in the laboratory, so I want to try different things!
FreeBSD The first *BSDs flavor which I began to get my hands dirty on is FreeBSD (since January, 2016). I wrote a simple manual (FreeBSD 101 Hacks) during that year.
OpenBSD I dived into OpenBSD last year (2017). Actually, I first learnt about OpenBSD is in 2014 (lack of money for the electricity bill, and this news sparked some discussion on Internet forums). I knew OpenBSD is famous for its security at that time.
Contribute to *BSDs Do some interesting stuff for *BSDs. Find *BSDs lack a neat command like lscpu on GNU/Linux to display CPU information (please refer stackoverflow). Implement it myself!
Physical CPU VS Logical CPU Physical CPU number = socket (1) Logical CPU number = Threads * cores * socket (1 * 2 * 1)
How does lscpu work on GNU/Linux? The source code is here. No rocket science, just read info from /proc and /sys:
Shocking news! Unfortunately, the procfs (/proc) is removed from *BSDs (At least on FreeBSD and OpenBSD. Please refer wikipedia).
sysctl(3) sysctl(3) is a library function which can get or set system information:
Example of using sysctl(3) The following is an example of getting CPU count by sysctl(3):
Get CPU info from sysctl(3) The sysctl(3) can only get limited information, and not all *BSD flavors support same options:
Get CPU info from CPUID (x86) The x86 CPU provides CPUID instruction to get CPU information. The compilers (gcc & clang) provide a __cpuid macro (the gcc s source code is here): The tedious work was reading the Intel&AMD documents to parse the returned value.
Example of using __cpuid Below is an example of getting CPU vendor from CPUID instruction:
Test Install OpenBSD/FreeBSD in virtual machines (host is GNU/Linux), and compare the result with lscpu output in host. Thanks for other developers testing on AMD CPUs (I only have Intel at hand) and other *BSDs distributions: DragonflyBSD, NetBSD, etc.
Current status The source code of lscpu for *BSDs is https://github.com/NanXiao/lscpu. Thanks for developers creating ports for FreeBSD, OpenBSD, MidnightBSD, and so on. Mainly support x86 families, not display enough info on other architectures.
A rewarding process What I have learnt: How to develop a *BSD program. The CPU knowledge, especially x86. Free/Open Source software change the world! Everyone can contribute to it: coding, testing, donating, and so forth.
