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

Re:BSoD

[Anonymous Coward]

> So the machine essentially BSoD'd, but it's not
> interesting?

Indeed. It might be "interesting" for Amazon and Google, to name at least two. The Google bug is currently being debugged on LKML.

Good Linux VM article

[MrResistor]

Here is an excellent article I found linked on rootprompt yesterday that goes into considerable detail about the 2.4 VM (or VMs, as the case may be).

Re:Makes me feel better...

[cicadia]

8 GB is only a 33-bit address space.

Even 2 TB is only 41 bits.

In theory, a 64-bit machine could handle 16,000 TB using only virtual memory, but there are a lot of reasons why you wouldn't be able to do that today.

Aside from the fact that having that much virtual space would be nearly totally useless (and the fact that you couldn't buy that much memory if you wanted to :), you will always be restricted by the capacity of the motherboard. The motherboard manufacturers are not forced to lay 64 address lines on the board, just because the CPU uses a 64-bit address bus internally.

I've been using 32-bit motherboards for a decade now, and I've never owned one which was physically capable of supporting 4GB of RAM.

Also, is the machine really a 64-bit architecture, in all areas? "64-bit" may be referring to the width of the data bus, not the address bus, which may still be only 33 or 34 bits wide. Very much like the "128-bit" GPUs -- they get all of the performance advantages of moving 128 bits at a time, but have no need for a 128-bit address space.