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Jeff Roberson Begins FreeBSD SMPng VFS Integration

Posted by Hemos on from the building-it-into-the-operating-system dept.

A FreeBSD User writes "Jeff Roberson has announced that he has has begun integrating the Giant-lock free VFS code into the FreeBSD 6.x development tree. These changes will permit the UFS file system to run on multiple CPUs at a time on SMP systems (hyper-threaded, dual-core, or regular SMP), leading to substantially improved efficiency. It will also permit the VFS code to be fully preemptible on uni-processor systems, improving interrupt handling latency. With this change, almost all of the FreeBSD kernel is able to run fully threaded and in parallel on multiple CPUs with much less contention. He anticipates merging this work as an "opt-in" feature to the FreeBSD 5.x branch in the future. He indicates that the testing will be "opt-in", i.e., this change will not be fully enabled by default for the time being, and that it will take a while (a few hours) to complete the merge, so users of the 6-CURRENT branch may want to hold off updating for a few hours while he finishes the merge. The work was sponsored by Isilon Systems."

4 of 54 comments (clear)

  1. BSD SMP VFS by Blakey+Rat · · Score: 4, Funny

    OMG WTF BSD SMP VFS? LOL!

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    Comment of the year
  2. Re:Why not in 5.x tree? by Geekboy(Wizard) · · Score: 4, Insightful

    because -stable is *NOT* the place for potentially destructive changes. it is possible that after this change has sat in -current for a few months, and its rock solid, it might be backported. Don't hold your breath though.

  3. Re:Nice idea. Linux? by moderators_are_w*nke · · Score: 4, Insightful

    I also think FreeBSD shot themselves in the foot by going with the MxN threading model, which sounds great in theory but's a real devil to get implemented to the point where it's correct and useful.

    Your kinda missing the point here. FreeBSD has got it implemented to the point where its correct and useful. Having done it kind of nullifies it the disadvantage of it being hard to do.

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    "XML is like violence. If it doesn't solve your problem, use more." - Anonymous Coward
  4. Re:Why not in 5.x tree? by Brandybuck · · Score: 4, Informative

    It's the difference between -STABLE and -CURRENT. The former only gets bug fixes, and if they've been tested to death, new drivers. As of 5.3, the 5.x branch became -STABLE, so for anything else, you have to use -CURRENT, and be patient and wait for 6.x to become STABLE.

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