FreeBSD s/390 Port in the works

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!"

Comments

Does this mean that...

[j-turkey]

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

Re:Does this mean that...

[questionlp]

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.

Re:Does this mean that...

[Strog]

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).

Re:More the merrier

[glitchvern]

Intrestingly enough NetBSD does not run on the 390.

Re:I'll check it out as soon as...

[Guy Harris]

The page for the port says it's being done on Hercules, which is a System/390 and z/Architecture simulator; the Hercules page claims it runs on Linux and 32-bit Windows, but it can probably be made to run on UNIXes other than Linux as well, assuming it doesn't Just Work out of the box.

Re:Kind of silly.

[treat]

Um, it's just one guy doing this, so far and he'll do whatever interests him, obviously. If all free software people did what was "needed" and not what was personally interesting to them, commercial OS's would be extinct by now.

Indeed. Look at all the poor free software that there are multiple, independent, poor versions of. (e.g. DVD/mpeg players, web browsers, word processors, financial software, file managers). If people had coordinated, with a goal of producing what was needed, instead of each writing their own software independently because of what they personally wanted, the free solutions would be so vastly superior to the commercial solutions that only the free ones would survive. Unfortunately, this almost never happens.

Re:I wonder what it would be like ...

[Jay Maynard]

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).