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IBM Operating Systems BSD

FreeBSD s/390 Port in the works 82

brad-x writes: "It appears that an enterprising gentleman has taken the time to port FreeBSD to the s/390. It needs some work yet, as his project page suggests, but if he makes it happen it will definitely be very cool. Check it out!"
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FreeBSD s/390 Port in the works

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  • by j-turkey ( 187775 ) on Wednesday July 03, 2002 @11:07AM (#3814380) Homepage
    Since the S/390 is a pretty parallel architecture...does this mean that the FreeBSD kernel is getting better at SMP?

    Does it run with more than 2 processors on the 390?

    Is the 2 CPU limitation an X86-only thing that I'm ignorant of (quite possible)?

    That's not to say that I don't love the BSD's, but they do have (or maybe they had) their limitations.


    -Turkey
    • by questionlp ( 58365 ) on Wednesday July 03, 2002 @11:14AM (#3814431) Homepage
      5.0-CURRENT includes SMPng which is supposed to improve MP performance dramatically by knocking away that single giant lock. I have heard people running FreeBSD on a quad Intel processor setup a while ago on freebsd-questions... though I'm not sure how well performance would scale compared to a dual processor setup of the same processor speed.

      I haven't been able to fully parse the boot log, so I'm not sure if it is utilizing more than one processor or not, but the thing that the write-up forgot to mention was that it was tested under the S/390 emulator (aka Hercules). I'm not sure what Hercules is and how it work per se... but it's still a huge jump forward for FreeBSD.
    • The complement to SMPng for FreeBSD (v5) is Kernel Scheduled Entities (KSE). The third milestone was just recently added to CURRENT: KSE-MIII Merged Into Current (5.0) [daemonnews.org].

      FreeBSD v5 will be a speed daemon. :)
    • > Is the 2 CPU limitation an X86-only thing that
      > I'm ignorant of (quite possible)?

      I've ran NetBSD on a quad-Xeon machine.

      - Hubert
    • It isn't really a 2CPU limitation per-sey. The problem is performance has diminishing returns as you go past 2 cpus. Giant kernel lock means that one cpu has access to the memory space at a time and this is why performance can't scale well with this design.

      The good news is that it works remarkably well on 1 or 2 cpu systems. It beat the performance of Linux 2.2 kernels and still gives 2.4 kernels a run for their money in most situations. When you start running mores cpus then performance will only go up a little bit so it really isn't worth it at that point.

      FreeBSD 5.0 will not have this limitation and will scale nicely. I'm just not sure how far it will go at first but you can be sure that it will improve from there now that a decent setup for SMP is in place now (with 5.0).
      • The good news is that it works remarkably well on 1 or 2 cpu systems. It beat the performance of Linux 2.2 kernels and still gives 2.4 kernels a run for their money in most situations. When you start running mores cpus then performance will only go up a little bit so it really isn't worth it at that point

        Do you have any benchmarks or anything (non-anecdotal)? I've been looking for a side-to-side type comparison for awhile.

        • I used to have several because I wondered the same questions. All my links are either dead or updated to 5.0 figures. Ignore the rest of my post if you consider it "too anecdotal".

          I've seen some inhouse testing with identical hardware with both Linux 2.4 and FreeBSD 4.x tuned for performance. They would go back and forth in some real-world testing with the edge in raw performance going to Linux more often. Usually the differences weren't that much but sometimes there was a clear winner.

          I would suggest that you get some hardware to test with and use both on this hardware in the situation(s) that you are going to put it in. It is real easy to get a system that each can support the hardware. If one or the other doesn't support the hardware you want or very well then go with the OS that supports the hardware well.

          For me, the real choice is outside of the scope of raw performance since they are fairly close (close enough for me at least). A couple factors I look at.

          1. A moderate to heavy loaded FreeBSD box still responds well while a Linux box under the same load will become extremely sluggish or unresponsive.

          2. Updating the system is more solid in FreeBSD than Linux. Apt-get and other mechanisms work well but usually have more issues for me at least. Following -stable is very easy in FreeBSD.

          3. Experience. Which system is the admin more comfortable with? If they have experience BSD or other traditional Unix then FreeBSD is the way to go. If they are more comfortable with Linux then it really needs to factor in to the choice.

          4. Number of processors. If the number goes over 2 then you need to go Linux or look into FreeBSD 5.0 if you can wait or run the development versions. Probably Linux will suit you better on your quad+ box for now at least. It will take some time to wring the most out of FreeBSD 5.x

          These are all opinions and suggestions. Use both in your setup and see which works for you. Alternately you could tell them both to take a hike and get an Irix box. That would open a whole new set of things to look at.
    • by Anonymous Coward
      FreeBSD SMP has always supported more than 2 CPUs. While FreeBSD 5.0 Developers Prerelease with SMPng might be more efficient, FreeBSD 4.6-RELEASE will boot today on a quad CPU x86 system. It will also boot on octal x86 CPU moterboard, with some hacking. Unfortunately, octal CPU x86 motherboards chipsets are rather different. These the mailing list archives for the details.
  • More the merrier (Score:2, Interesting)

    by atcurtis ( 191512 )

    The more platforms supported, the merrier it will be.

    Although, I don't expect to see FreeBSD on anywhere near the same number of platforms as NetBSD.

    I'd like to see FreeBSD 5 running on RS/6000 hardware... That would be nice ;)
  • The thing I think is interesting about this port is that it puts freebsd on the s/390 while NetBSD [netbsd.org] isn't. They do say a port of NetBSD to the s/390 would be relatively staightforward though.
  • to compile the linux kernel on this thing.

    to have a Beowolf cluster -- oh never mind!

    Before people get too excited about topics such as SMP, kernel threads, and I/O devices -- it only partially boots on a mainframe emulator. This is a VERY LONG WAYS OFF from asking, "so where can I download the ISO images?".
    • Before people get too excited about topics such as SMP, kernel threads, and I/O devices -- it only partially boots
      Yeah...the project isn't to the point where it's usable for anything but system hacking yet.

      on a mainframe emulator.
      If it runs on Hercules, it'll run on the real hardware. Before you pooh-pooh the use of an emulator, consider that Alan Cox uses Hercules for S/390 work (not all of it, but quite a bit).

  • The question is not whether *BSDs are dying, but rather whether S/390s are dying.

    Unix machines have had more processing power than S/390s for years now, but they did commonly not support block-mode terminals (like S/390's 3270), and therefore it was difficult to implement host-/terminal-based applications on unix-systems without causing too much network traffic.

    AS/400's (aka iSeries 400) have got 5250-terminals, which are quite the same as the 3270's, but a few years ago AS/400's did not have as much processing power and/or disk capacity as mainframes. Recent AS/400's are mainly based on pSeries-like hardware, with the same powerful POWER4 processors, lots of cache memory and lots of main storage (RAM).

    Since the biggest AS/400s are now more powerful than the biggest z/900 but also are more mainframe-like than the pSeries, it could be possible, that IBM is going to replace the S/390's with the more modern AS/400's.
  • the BSDs love you they are your friends (at least freebsd anyways) =*

Two can Live as Cheaply as One for Half as Long. -- Howard Kandel

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