Linked by Thom Holwerda on Thu 16th Apr 2009 19:54 UTC
General Unix Even though the old-world UNIX operating systems, like IRIX and HP-UX, have been steadily losing ground to Linux for a long time now, they do still get updated and improved. HP-UX 11i v3 is supposed to get update 4 tomorrow, with a host of new features that won't excite you if you're used to Linux, but they're still pretty useful for HP-UX users.
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RE[2]: Linux does not scale
by Kebabbert on Sun 19th Apr 2009 22:09 UTC in reply to "RE: Linux does not scale"
Kebabbert
Member since:
2007-07-27

I would hardly call 64 cpus good scaling. Prior to Linux 2.6.27 the kernel was 250 times slower on 64 cpu systems. (Solaris people have long time been talking about hundreds of cpus and many more threads).
http://kernelnewbies.org/Linux_2_6_27




Those SGI supercomputers with 4096 cpus, how old are they? Which Linux kernel version did they use? Linux v2.2? v2.4? Oh yes, the 2.4 Linux scales very well. Here we have some Linux scaling experts debunking the FUD that Linux scales badly. They clarify everything about the FUD:
http://searchenterpriselinux.techtarget.com/news/article/0,289142,s...

"Linux has not lagged behind in scalability, [but] some vendors do not want the world to think about Linux as scalable. The fact that Google runs 10,000 Intel processors as a single image is a testament to [Linux's] horizontal scaling.

Today, Linux kernel 2.4 scales to about four CPUs

-With the 2.6 kernel, the vertical scaling will improve to 16-way. However, the true Linux value is horizontal scaling.

Q: Two years from now, where will Linux be, scalability-wise, in comparison to Windows and Unix?
A: It will be at least comparable in most areas"


Linux scales to 10.000 cpus in one single image in current v2.4, and in Linux 2.6 the kernel will improve to 16-way. Huh? Is it only me that sees a contradiction? You have bought everything about Linux scaling well and being well coded.

When I say that Linux scales bad, even the Linux experts agree, as I have proved. I am not trolling. I find it extremely hard to believe that in v2.4 Linux scaled bad (2-4 CPUs) and in 2.6 it suddenly scales better than Solaris does with hundreds of cpus? It takes decades to scale well. What am I, a fool? Can't I think? Do I buy everything? No critical thinking? Do the world a favour, and apply some critical thinking on everything you hear.

Linux scales well on large clusters, yes. But that is NOT Big Iron. How many times must I repeat that? Read my first post again. When people says Linux scales well (which it does) then they talk about clusters.

In other words; Linux scales well HORIZONTALLY, but sucks VERTICALLY. Get it? How many times must I say this? It is explained on wikipedia. Read it. Twice. Slowly.




Linux Kernel developer Andrew Morton
http://lwn.net/Articles/285088/

"it would help if people's patches were less buggy."





Let me say this again, apparantely some people have problems understanding this: If I modify a kernel to scale well, the kernel does not scale well. The MODIFIED kernel scales well.

I can modify C64 to run on a large cluster, but no one would hardly say C64 scales well. The modified version does, but not C64. If modifier Linux runs on large cluster, fine. But that does not mean standard Linux scales well. Due to limitations, standard Linux does not run without modifications. But Solaris does run on big iron with hundreds of CPUs with the same install DVD. It scales well.





trasz; The fact that Linux uses spinlocks is one of the reasons that its performance drops noticeably under high load on many CPUs. Other operating systems use fully functional mutexes, along with interrupt threads.

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