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One of the main criticisms I hear about OpenBSD is that it's performance isn't as good as Linux. I've looked at a couple articles quoting benchmark comparisons,

One of the main criticisms I hear about OpenBSD is that it's performance isn't as good as Linux. I've looked at a couple articles quoting benchmark comparisons, so I'll assume for the sake of argument that it's true. The thing is that I don't care. I'm still an OpenBSD advocate and run it whenever I get the chance. I don't actually care about performance at that level. What matters more to me is consistency, and good man pages. I imagine more people are like me, but the thing about performance measurements is they're quantifiable. They can be easily measured. We all probably over optimize to some degree, whether we're C developers or not. There's just something satisfying about getting a quantifiably better score. This is why we get code that sacrifices almost everything for runtime speed.

talideon 12y ago
The slowness isn't a generally impacted much by stuff like this. It's more things like OpenBSD's poor multicore performance that are the issue. Just compare the performance of FreeBSD's multithreaded PF to OpenBSD's singlethreaded PF. Still, none of this matters, because there's one major guarantee that the OpenBSD devs try to fulfil: correctness.
- imanaccount247 12y ago
  The thing is, the "slowness" in question is different every time someone wants to talk about it. Because people don't benchmark it, don't actually know what is slower and by how much, and just go on the "common knowledge" that openbsd is slow. The openbsd is slow meme was going strong in the 1990s, when it didn't support SMP at all and 99% of the people talking about it were using a single CPU.
  - wahern 12y ago
    It's different because the slowness is across the board. FreeBSD and, especially, Linux have optimizations all over the place. A call to time(2) or gettimeofday(2) is hundreds of times faster in Linux than on OpenBSD. In most scenarios the difference doesn't matter. But it does matter in, e.g., an asynchronous network service with lots of events with timeouts being constantly registered. I prefer OpenBSD, and I like that they focus on correctness, bugs, and more high-level features. I run all my personal services on OpenBSD. But commercially and at scale I run Linux, and treat each box as a throw-away in terms of security.
    - imanaccount247 12y ago
      >A call to time(2) or gettimeofday(2) is hundreds of times faster in Linux than on OpenBSD Got a link to those benchmarks? Did anyone file a bug report? >But commercially and at scale I run Linux Wouldn't netbsd be a better option?
      - Dylan16807 12y ago
        I doubt it's a bug. That sounds like the overhead of a syscall vs. a memory-mapped page.
        imanaccount247 12y ago
        How does that make it not a bug? They've repeatedly responded to the "openbsd is slow" meme by pointing out that they do not have the time to benchmark anything, and if people do find slow things they should submit bug reports so they can be fixed. Nobody has ever submitted such a bug report.
        Dylan16807 12y ago
        It's as fast as any other syscall, it's just lacking in special optimizations.
        imanaccount247 12y ago
        And the part where the developers explicitly say being slower than necessary is a bug and should be reported as such means it is a bug. This honestly is not complicated.
        Dylan16807 12y ago
        If slower than absolutely necessary is a bug I can probably report 99% of lines in the codebase. Perfection is astonishingly difficult.
- Mordak 12y ago
  I suppose there are probably large groups of people who care about multicore performance on the metal, but my dominant use case is herds of single core VMs, each doing one thing (well!). In this case, host CPU and memory consumption matter, and OpenBSD is very hard to beat in this metric. My OpenBSD VMs normally consume 1/4 of the CPU time and run happily in half the RAM as my FreeBSD, Linux and Windows VMs. I don't know if there is a significant performance difference on a single CPU, but I certainly don't have any complaints about performance.

talideon 12y ago

The slowness isn't a generally impacted much by stuff like this. It's more things like OpenBSD's poor multicore performance that are the issue. Just compare the performance of FreeBSD's multithreaded PF to OpenBSD's singlethreaded PF. Still, none of this matters, because there's one major guarantee that the OpenBSD devs try to fulfil: correctness.

imanaccount247 12y ago
The thing is, the "slowness" in question is different every time someone wants to talk about it. Because people don't benchmark it, don't actually know what is slower and by how much, and just go on the "common knowledge" that openbsd is slow. The openbsd is slow meme was going strong in the 1990s, when it didn't support SMP at all and 99% of the people talking about it were using a single CPU.
- wahern 12y ago
  It's different because the slowness is across the board. FreeBSD and, especially, Linux have optimizations all over the place. A call to time(2) or gettimeofday(2) is hundreds of times faster in Linux than on OpenBSD. In most scenarios the difference doesn't matter. But it does matter in, e.g., an asynchronous network service with lots of events with timeouts being constantly registered. I prefer OpenBSD, and I like that they focus on correctness, bugs, and more high-level features. I run all my personal services on OpenBSD. But commercially and at scale I run Linux, and treat each box as a throw-away in terms of security.
  - imanaccount247 12y ago
    >A call to time(2) or gettimeofday(2) is hundreds of times faster in Linux than on OpenBSD Got a link to those benchmarks? Did anyone file a bug report? >But commercially and at scale I run Linux Wouldn't netbsd be a better option?
    - Dylan16807 12y ago
      I doubt it's a bug. That sounds like the overhead of a syscall vs. a memory-mapped page.
      - imanaccount247 12y ago
        How does that make it not a bug? They've repeatedly responded to the "openbsd is slow" meme by pointing out that they do not have the time to benchmark anything, and if people do find slow things they should submit bug reports so they can be fixed. Nobody has ever submitted such a bug report.
        Dylan16807 12y ago
        It's as fast as any other syscall, it's just lacking in special optimizations.
        imanaccount247 12y ago
        And the part where the developers explicitly say being slower than necessary is a bug and should be reported as such means it is a bug. This honestly is not complicated.
        Dylan16807 12y ago
        If slower than absolutely necessary is a bug I can probably report 99% of lines in the codebase. Perfection is astonishingly difficult.
Mordak 12y ago
I suppose there are probably large groups of people who care about multicore performance on the metal, but my dominant use case is herds of single core VMs, each doing one thing (well!). In this case, host CPU and memory consumption matter, and OpenBSD is very hard to beat in this metric. My OpenBSD VMs normally consume 1/4 of the CPU time and run happily in half the RAM as my FreeBSD, Linux and Windows VMs. I don't know if there is a significant performance difference on a single CPU, but I certainly don't have any complaints about performance.