Don't hurt me...yet

[victorcao]

Alright this just for some feedback, so don't hurt me.

What do you experts think about porting linux onto a Apple G4? I've done it in the lab and it works great so far, of course we've been only doing low-end work. We've been using Yellow Dog Linux for awhile and it runs okay, still waiting for 2.0. Anyway, I need some feedback from you people. Will Linux-On-Mac survive?

I quote Lorenz:
"Linux sees to like memory - lots of RAM which you are planning for - but also lots of cache in the CPU. I got this clear impression from reading the rare kernel compile bencmarks on THG."

Now if Linux likes memory, then 1 GB of RAM would be exceptional?
If Linux likes CPU cache, then would 1 MB be exceptional.

Again some feedback, until then no Mac bashing. I'm still true to the PC.

-Victor

 

[Kelledin]

Linux's memory handling is something a lot of people find peculiar.

One thing to note is that the Linux kernel uses memory for all sorts of things--buffers, caching, etc. etc. etc. Most kernels besides Linux do this also. There are some scenarios where parts of the kernel can get more benefit the more memory you give it, supposedly up to infinity or some extremely large amount of RAM. Generally, memory used for this purpose is categorized as "cached" memory. The benefit of this extra memory may often be very slight, but for the sake of getting the most out of your RAM, Linux will dole out almost all available RAM for this purpose. When more needy applications request it, Linux usually takes the RAM and allocates it to these applications.

A consequence of this is that no matter how much memory you have, Linux always seems to be using almost all of it. Generally you can run Linux on a minimal (<8MB) amount of RAM; for some purposes it will run just fine. For loading a full GUI desktop, you might want 32-128MB of RAM. For database serving, it's not uncommon to see several GB of RAM in a system.

As for CPU cache...how much use Linux will get out of that is really more application dependent. I'd start thinking about upgrading CPU cache only after I'd satisfied the system's RAM hunger (to the point that it uses only no less than 25% for cache). Of course, I'm living in an Intel world, where getting a larger cache means going with a much more expensive Xeon CPU. It might be a bit different in the Mac world...

Oh, one detail: Linux's caching behavior must have changed a little bit between kernel 2.4.1 and 2.4.4. At this instant, my system only uses 212MB of my 512MB for cache and leaves 177MB free. I bet you have <A HREF="http://www.surriel.com/" target="_new">Rick van Riel</A> to thank for that...and you might be interested in some of his kernel patches also.

Kelledin

"/join #hackerz. See the Web. DoS interesting people."

 

[victorcao]

Thanks for the info.

-Victor