Linux 2.2 and 2.4 VM Systems Compared

Derek Glidden writes "I got sick of trying to figure out from other people's reports whether or not the 2.4 kernel VM system was broken or not, so I decided to run my own tests, write them up and post them online. The short conclusion is that the 2.4 VM rocks when compared with 2.2, but there's more to it than just that."

Comments

Somebody help me out here

[rho]

Quite often I get the feeling that Linux and BSD are doing quite a bit of "me-too"-isms in an attempt to catch up with the mainstream OSes--including MS, Apple and commercial Unixen.

I read this story and wonder if I should still be getting the same feeling -- isn't a VM subsystem mostly a solved problem? Or am I reading this wrong, and this is merely tweaking and specialization?

Since I'm no Alan Cox (I'm closer to Alan Thicke), I can't see the truth of the matter, but I get the feeling that we're doing a lot of walking in a tight circle on the path, while others have already left the forest.

Re:Somebody help me out here

[DataPath]

It's hard to say if the VM subsystem has been completely reworked in the MS operating systems. It's all closed source. But I think it's a fair guess that NT and 9x had completely different VM subsystems, and in addition, that the Win2k VM subsystem is likely a complete rework of the NT 4 VM. I guess it's something that happens from time to time... someone thinks of a different way of doing things that changes how everything works together, and it makes something faster, something slower.

Re:Somebody help me out here

[Ami Ganguli]

Another factor is probably the tremendous range of hardware and workloads that Linux tries to handle. I don't think any other OS attempts to work well on watches and mainframes (and everything inbetween) while using the same code base.

This is all well and good

[duffbeer703]

But the fact remains is that this VM holy war should have been resolved in the 2.3 series of kernels.

The number of major problems and architectural changes that are being made to the supposedly 'stable' branch of Linux kernel is really run amok.

I'm sure there's plenty of outrages to come as bad bugs are found in the volume manager and other new elements of 2.4

The Unreal Tournament test

[Miles]

Just a possibly interesting data point. I played Unreal Tournament with 2.4.12-ac5 and 2.4.10 (both from Debian). 2.4.10 always seems to work fine for extended periods of Lan play (as both a client and server), whereas the 2.4.12-ac5 choked after a few games--the swap ended up being nearly all used up.
Of course, this was hardly a scientific test, but I think I'll stick to something proven for now.

Check out Linux Weekly News and Kernel Traffic

[cpeterso]

(Yes, I spend an hour a day reading the kernel mailing list.)

I'm too lazy to read LKML, but I am interested in the happenings of the Linux kernel development. I highly recommend Linux Weekly News' kernel news (updated every Thursday) and Kernel Traffic , an in depth summary of the week's LKML happenings (usually updated every Sunday or Monday).

Linux needs professionalism in release management

[Sara Chan]

I have some concern about how all these changes appear to businesses. Linux is supposed to be a high-quality alternative to other operating systems. Yet we've recently had a production kernel that failed to even compile, and there have been major upheavals to the "stable series" VMM, which sometime degrade reliability or performance. This isn't going to impress, and it gives competitors valid ammunition.

Almost all successful enterprises have to overcome a hurdle: how to transition from the "just for fun" start-up stage to the "managed with professionalism" stage. Ideally, fun is kept along with the professionalism. Note that even at Microsoft, B. Gates now lets S. Balmar (CEO) and R. Belluzzo (President and COO) manage things. Gates is the "chief software architect" and Microsoft is still his, but others do the managing.

Linux needs more professionalism in the management of releases, I believe.