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DragonFlyBSD 3.6 Brings AMD/Intel Graphics Drivers & Better SMP Scaling 48

Posted by timothy
from the not-just-hovering-there dept.
An anonymous reader writes "DragonFlyBSD 3.6 was released [Monday] with the big new features being dports, Intel and AMD Radeon KMS kernel graphics drivers, major SMP improvements, and improved language support. Dports is the new package management system based upon the FreeBSD Ports collection and replaces pkgsrc as the default; over 20k packages are available via dports. Major SMP scaling improvements come via reducing lock contention within the kernel and other multi-core enhancements. The Intel and Radeon graphics drivers on DragonFlyBSD were ported from the FreeBSD kernel, which in turn were ported from the upstream Linux kernel."
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DragonFlyBSD 3.6 Brings AMD/Intel Graphics Drivers & Better SMP Scaling

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  • by Sarten-X (1102295) on Tuesday November 26, 2013 @11:41AM (#45526443) Homepage

    Has anybody else noticed that over the last decade, almost all of the DragonFlyBSD release stories have been posted by timothy, and the majority of those were submitted anonymously?

    It's not a particularly popular distro, coming in at #77 [] today, in an unscientific poll. I get that it's news for nerds, but I'm starting to suspect a wee bit of bias.

    • by geek (5680) on Tuesday November 26, 2013 @12:13PM (#45526857)

      Of the BSD's DragonFly is probably one of the more important and active ones. The filesystem they use is one of the biggest advancements in BSD in a long time. I'm not a DragonFly user but I do track it in hopes of one day using it at a point that it fits my needs. FreeBSD 10 however is addressing all of my concerns so DragonFly may slip away from my sites soon.

    • by Anonymous Coward

      You might note that about half of's [] stories are from anonymous readers. It's just that this site has grown hostile towards the BSDs, as evidenced by many BSD vs GPL threads which degenerate into strawmen and insults. They probably have driven out many BSD-using folks here, or at least made them not bother with registration.

      (Try to read the comments posted on those stories. The signal-to-noise ratio is dismal.)

      Oh, and I was one of those anonymous submitters for a past DFly r

    • Re: (Score:2, Informative)

      by bluefoxlucid (723572)

      DragonflyBSD is the only interesting BSD. Minix is the other interesting Unix-like. Dragonfly has a whole hell of a lot of novel concepts or novel implementations of concepts: HAMMERFS (runs 30 second snapshots for 24 hours, then 1 day snapshots, then 1 week, 1 month--a versioning file system, semi-useful), checkpointing with freeze/thaw (you can actually freeze an application and reboot, to the point that you can even move the application to another machine running Dragonfly with the same files at the

      • by unixisc (2429386)
        I think an interesting project might be to have pFsense or m0n0wall redone using Minix, rather than BSD as the kernel. With full IPv6 support
  • You know, I hear a lot of folks complain about Linux fragmentation, tyrany of choice, etc. But at least we can say that, for the most part, there is one true canonical Linux kernel (Linus' tree) and all the other kernels are for the most part shallow forks tweaking a few things.

    Now in BSD land we have NetBSD, FreeBSD, OpenBSD, and DragonflyBSD, each with their own true kernel.


    If the project goals have diverged so widely as to take the kernel off in a completely different direction from all the ot

    • How widely do the various BSD kernels actually diverge?

      It is true that Linux has resisted fragmentation pretty well, with the exception of the various fossilized versions usually present at roughly 80% of the completeness that GPL compliance demands in the unending waves of shitty BSPs for assorted hardware, may they sink into hell. That is the 9th circle of hell when it comes to 'Linux fragmentation'. x86 is downright civil, by contrast, with most of the fragmentation, real and alleged, occurring above
      • Dragonfly BSD is substantially different from FreeBSD in that it's not using the same fundamental memory management or task scheduling strategies.
        • Forgive my ignorance; but how modular are memory management and task scheduling relative to what would seem (to my admittedly untrained eye) to be the two big areas where fragmentation would be a killer: kernel drivers and applications/DEs/etc. (including those of significant complexity, not just Hello World).

          If Dragonfly can still use FreeBSD drivers, and run common Linux and BSD applications, they may or may not have a particularly good memory manager or task scheduler; but if somebody wants to go off
          • It's significantly critical that drivers are either incompatible or sub-optimal if migrated from one base to another. In theory this can be separated; in practice, monoliths don't separate in that way.

    • by unixisc (2429386)

      Generally, FreeBSD seems be the popular face of BSD, just like Red Hat is of commercial Linux. OpenBSD & NetBSD seem to have a relatively low base in comparison, while the others, such as DragonFly are even smaller. Also, most of the BSD clones - GhostBSD, MidnightBSD, et al are FreeBSD based, as opposed to the other 2.

      OTOH, Minix is its own (micro)kernel and uses NetBSD userland, as opposed to FBSD. Interesting.

  • It's a fork of FreeBSD 4.8 from 2003. I ran the most recent freebsd and pc-bsd and both are rock solid. It was easier to install flash player on bsd than opensuse 13.1(it did not work even installing from the terminal). I ran linux open source applications just fine with no issue on pc-bsd 9.2.

    • by unixisc (2429386)
      If FBSD/PC-BSD simply added Hammer/2 support, wouldn't that make DragonFly instantly irrelevant? B'cos then it would just be a fork of FBSD 4.8 & nothing more
    • The desktop experience under Linux is still better than of PC-BSD. I did some experimenting with PC-BSD and everything had a bit crusty and unpolished feeling. The robustness of BSDs is of course very good thing, but I need a good desktop too. Of course the PC-BSD guys have made installing the desktop much more easier, so they still get a plus from me.
  • Check [], there's a list of random links under the DEVFS bullet point.

  • by m.dillon (147925) on Tuesday November 26, 2013 @01:25PM (#45528079) Homepage

    This release removes almost all the remaining SMP contention from both critical paths and most common paths. The work continued past the release in the master branch (some additional things which were too complex too test in time for the release). For all intents and purposes the master branch no longer has any SMP contention for anything other than modifying filesystem operations (such as concurrent writing to the same file). And even those sorts of operations are mostly contention free due to the buffer cache and namecache layers.

    Generally speaking what this means is that for smaller 8-core systems what contention there was mostly disappeared one or two releases ago, but larger (e.g. 48-core) systems still had significant contention when many cores were heavily resource-shared. This release and the work now in the master branch basically removes the remaining contention on the larger multi-core systems, greatly improving their scaling and efficiency.

    A full bulk build on our 48-core opteron box took several days a year ago. Today it takes only 14.5 hours to build the almost 21000 packages in the FreeBSD ports tree. These weren't minor improvements.

    Where it matters the most are with heavily shared resources, for example when one is doing a bulk build on a large multi-core system which is constantly fork/exec'ing, running dozens of the same process concurrently. /bin/sh, make, cc1[plus], and so on (a common scenario for any bulk building system), and when accessing heavily shared cached filesystem data (a very common scenario for web servers). Under these conditions there can be hundreds of thousands of path lookups per second and over a million VM faults per second. Even a single exclusive lock in these paths can destroy performance on systems with more than 8 cores. Both the simpler case where a program such as /bin/sh or cc1 is concurrently fork/exec'd thousands to tens of thousands of times per second and the more complex case where sub-shells are used for parallelism (fork without exec)... these cases no longer contend at all.

    Other paths also had to be cleaned up. Process forking requires significant pid-handling interactions to allocate PIDs concurrently, and exec's pretty much require that locks be fine-grained all the way down to the page level (and then shared at the page level) to handle the concurrent VM faults. The process table, buffer cache, and several other major subsystems were rewritten to convert global tables into effectively per-cpu tables. One lock would get 'fixed' and reveal three others that still needed work. Eventually everything was fixed.

    Similarly, network paths have been optimized to the point where a server configuration can process hundreds of thousands of tcp connections per second and we can get full utilization of 10GigE nics.

    And filesystem paths have been optimized greatly as well, though we'll have to wait for HAMMER2 to finish that work for modifying filesystem calls to reap the real rewards from that.

    There are still a few network paths, primarily related to filtering (PF) that are serialized and need to be rewritten, but that and the next gen filesystem are the only big ticket items left in the entire system insofar as SMP goes.

    Well, the last problem, at least until we tackle the next big issue. There's still cache coherency bus traffic which occurs even when e.g. a shared lock is non-contended. The code-base is now at the point where we could probably drop-in the new Intel transactional instructions and prefixes and get real gains (again, only applicable to multi-chip/multi-core solutions, not simple 8-thread systems). It should be possible to bump fork/exec and VM fault performance on shared resources from their current very high levels right on through the stratosphere and into deep space. Maybe I'll make a GSOC out of it next year.

    The filesystem work on HAMMER2 (the filesystem successor to HAMMER1) continues to progress but it wasn't ready for even an early alpha release this release. The core media formats are stable but the freemap and the higher level abstraction layers still have a lot of work ahead of them.

    In terms of performance... well, someone will have to re-run bechmarks instead of just re-posting old stuff from 5 years ago. Considering the SMP work I'd expect DFly to top-out on most tests (but there's still always the issue of benchmark testers just blindly running things and not actually understanding the results they post about). Database performance with postgresql still requires some work for large system configurations due to the pmap replications (due to postgres fork()ing and using mmap() now instead of sysv-shm, e.g. if you used a large 100GB+ shared memory cache configuration for the test). We have a sysctl to enable page table sharing across discrete fork()s but it isn't stable yet... with it, though, we get postgres performance on-par with the best linux results in large system configurations. So there are still a few degenerate cases here and there that aren't so much related to SMP as they are to resource memory use. But not much is left even there.

    Honestly, Slashdot isn't the right place to post BSD stuff anymore. It's too full of immature posts and uninformed nonsense.


    • Honestly, Slashdot isn't the right place to post BSD stuff anymore. It's too full of immature posts and uninformed nonsense.


      Agreed - The BSD section used to be somewhat lively. There's an awful lot of hostility towards the BSDs as they're not Linux. People feel really threatened when there is an alternative to their favorite OS. I also have to laugh at posts about BSD fragmentation. How many Linux distros are there now? Oh, but they're all related! Of course, the BSDs share ancestors, so they're related, too.

    • The filesystem work on HAMMER2 (the filesystem successor to HAMMER1) continues to progress but it wasn't ready for even an early alpha release this release. The core media formats are stable but the freemap and the higher level abstraction layers still have a lot of work ahead of them.

      Have you considered space maps [] for tracking free space? I thought that was one of the more interesting ideas in ZFS.

      Anyway, great work on the SMP scalability. It is refreshing to see a concerted effort in reworking the system to be more SMP friendly, rather than the profuse and convoluted locking that most others have adopted.

      • by m.dillon (147925)

        I've read the space map work but there are several issues that make them impractical for H2. The main one is that H2 snapshots are read-write (ZFS snapshots are read-only). Secondarily, my experience from H1 is that any complicated ref-counting or space accounting can lead to hidden corruption. Even if we assumed that the media data validation mechanism (a CRC or cryptographic hash) detects all media issues, there is still the problem of software complexity introducing bugs at a higher level.

        So H2 is goi

    • by Burz (138833)

      ...hundreds of thousands of tcp connections per second...

      Hold on there, I'm still using DNet!

    • by oddtodd (125924)

      Thanks for that post Matt, there's still a few old skool folks about that like this stuph. /. has a lot of noise, but there's still some signal in there now and again.

Theory is gray, but the golden tree of life is green. -- Goethe