Slashdot Mirror
Linux Kernel Performance How Will 2.6 Measure Up?
An anonymous reader writes "This story offers some interesting performance comparisons between the latest stable Linux kernels (2.4.x) and the latest development Linux kernels (2.5.x), comparing performance on both a single processor and dual processors. These numbers help validate that the upcoming 2.6 kernel will outperform the current 2.4 kernel, at least in some instances..."
Of course, the real solution would be to not need to compile software (plug plug :)
What is the weakest specced machine that anyone here is getting productive/useful work with Linux done on? Do people use Linux on 468s at 12mhz? P75s? Just curious.
Linux marketing through Slashdot? Hehehe... next we'll have microsoft and intel buying banner space... Oh...
Diplomacy is the art of saying "nice doggie" whilst looking for a rock
The whole point of Linux development is to , explore strange new algorithms, seek out new drivers and new filesytems, to boldly code where on one has coded before :)
As with all experimental endeavours, you do sometimes get better results, sometimes worse, but from those mistakes lessons are learned and better methods are devised.
It's not about "marketing". It never was.
"Backups are for wimps. Real men upload their data to an FTP site and have everyone else mirror it." -- Linus Torvalds
Amazing, I've been running FreeBSD since 2.8 and I've never had an unresponsive system even while doing a build world; I guess the 2.4 kernel is alot worse than imagined.
This is, by and large, the fault of the scheduler, largely unchanged in 10 years and described by Linus, even whilst he wrote it, as a 'hack'. However, it worked, and Linus, being the extremely sensible and conservative maintainer that he is, kept it until recently - process schedulers are difficult things to get right, and their performance is crucial to the performance of the kernel as a whole. Not to mention that for the tasks that Linux has been used for historically, primarily low-volume server tasks on low-end hardware, it isn't really a bottleneck.
Still, the scheduler has been gutted and rewritten for 2.6 by Ingo Molnar - the now somewhat-famous O(1) scheduler, which performs much more fairly under load, and dispenses with almost all of the strange pauses and scheduling glitches under load. Current vendor kernels based on 2.4 (Red Hat's and SuSE's at least, I think) have had the O(1) scheduler backported to them as well. In fact, if you're running near enough any current 2.4 kernel other than mainline, you get the O(1) scheduler and your share of scheduling fairness.
The new scheduler is also a fundamental basis for Linux 2.6's new NPTL 1:1 threading, which has so far proved spectacularly (record-breakingly?) fast. Hmm, on second thoughts, perhaps I probably shouldn't mention threads and FreeBSD in the same post. I mean, isn't this the same FreeBSD that's still waiting for a single half-decent pthread implementation? Oh well, better hope 5.0 is out soon...
Whenever I see posts that say "*BSD is better than Linux", most of the time they are referring to some userland aspect of *BSD compared to some GNU/Linux distro, and not "Linux" the kernel itself. Which isn't really fair IMHO, since most of the time it's not "Linux"'s fault for whatever is being bashed at the time.
Not exactly right. There's no question it was very much Linux's fault for having a less than totally robust virtual memory manager for a number of years. In the push to add features such as memory above 4 gigabytes, stability in corner case and swap performance kind of got left behind. This has been corrected in Linux 2.5 with the new reverse-mapped VM, which sacrifices a little raw speed in such things as process forking (look closely at the benchmarks and notice 2.5 is slightly slower in Con's "process load" benchmarks) and mallocing, in return for far better and more predictable swapping performance. Plus, the new VM provides a better base for new developments you'll see in the next series, such as active memory defragmentation. Over time, we're likely to win back the slight performance losses in (certain areas of) the 2.5 vm, and then some. In the meantime, there's no question that 2.5 is the smoothest running Linux kernel ever.
BSD continues to edge out Linux in some areas, notably NFS server performance. It used to be, BSD had a lot more advantages over Linux than it does now (the BSD developers are darn good). But in the end, Linux offers a much broader range of hardware support and has way more programmers working on it, so slowly but surely is catching up and surpassing in the few areas where BSD still has the edge. If I had to speculate about why Linux gets the massive herds of programmers, I'd say it's because of the license - many volunteer programmers prefer the GPL because of the legal guarantee that their work will remain open and not end up fading away because it had to compete against some heavily-funded proprietary product based on their own code. However, it's clear there are enough top-flight programmers to whom such considerations are unimportant to keep the BSDs not only alive, but vibrant.
See here for a look at some of the nice features BSD, and some ideas for the future. In case anybody thinks the much-talked-about rivalry between Linux and BSD is some kind of war, it isn't. BSD and Linux people often work together, there is a lot of cross-pollination, and the prevailing attitude is one of mutual respect. At the end of the day, it's worth noting that, technically speaking, the closest rival to Linux in the operating system space is another open source project.
Have you got your LWN subscription yet?