SGI: Development

Any chance to have an executable version for my O2?

I'm just curious...

run2.sh on my 2 best machines



Anyone can explain to me what is user time? and why it's actually higher on my Origin2400 ?

Oh and another strange behavior, it seems i lose a router link when second test starts... Doesn't seem to affect the system, but it always shuts this link down each time it starts the second test of the run2.sh

Quick crash course:
"real" time is also commonly called "wallclock" - it's how much actual, measurable time the program spent from when you invoked it to when it finished. Generally measured using a real-time clock in the system, if it's available.
"user" time is an estimate of how much CPU time was spent in user code (i.e. the program itself). It's usually measured by counting instruction cycles.
"system" time is an estimate of how much CPU time was spent in system code (i.e. the kernel and syscalls). Again usually measured by counting instruction cycles.

This is a grossly simplified explanation, but user time is higher on your Origin 2400 because it has slower CPUs - it had to do about 4 hours of processing "work" to match your Octane's 3 hours. It could just slice it up into 8 pieces, so it took less real time.

Oh! explained like that i can now fully understand the results.

So it also means, that if i had another module (16 cpus total), it would then take about 20mins of real time instead of 40mins, but would still sum up to 4h of user time.

Bill622 wrote: Any chance to have an executable version for my O2?

Code: Select all

# ./fractbatch: Exec format error. Wrong Architecture.
# file fractbatch
fractbatch:     ELF 64-bit MSB mips-4 dynamic executable (not stripped) MIPS - version 1
#


I'm just curious...

Is the O2 not a 64-bit-machine?
It's 10 years ago that I worked on a O2.

Here is another executable for you, compiled with compiler-switches -n32 -mips3:
http://www.martin-steen.de/sgi/n32/fractbatch.gz

Best regards,
Martin

Martin Steen wrote: Is the O2 not a 64-bit-machine?

It has a 32-bit kernel, since there's really no reason to run it in 64-bit mode due to the 1GB memory limit (it can, however, still use 64-bit instructions -- it just lacks the kernel support and libraries that use a 64-bit address space).

It is more efficient to run MIPS4 N32 code on all SGI machines that have an R5k or better CPU inside (and MIPS3 N32 for R4k). Compile it as 64-bit only if your app uses more than 2GB of memory, otherwise it will just cause a slow down and use more memory.

ShadeOfBlue wrote:

Martin Steen wrote: Is the O2 not a 64-bit-machine?

It has a 32-bit kernel, since there's really no reason to run it in 64-bit mode due to the 1GB memory limit (it can, however, still use 64-bit instructions -- it just lacks the kernel support and libraries that use a 64-bit address space).

It is more efficient to run MIPS4 N32 code on all SGI machines that have an R5k or better CPU inside (and MIPS3 N32 for R4k). Compile it as 64-bit only if your app uses more than 2GB of memory, otherwise it will just cause a slow down and use more memory.

So the O2 has a 64-bit CPU, but it cannot run 64-bit code because the kernel and the libraries are
32-bit? That's good to know, if one is going to use posix memory mapping (mmap) with big files.
(on my job I have to deal with satellite images that can be 200GB large).

Best regards, Martin

henrycault wrote: run2.sh on my 2 best machines

Oh and another strange behavior, it seems i lose a router link when second test starts... Doesn't seem to affect the system, but it always shuts this link down each time it starts the second test of the run2.sh

front_link.jpg

That is indeed very strange. There is no network-code in the program.

Martin Steen wrote: So the O2 has a 64-bit CPU, but it cannot run 64-bit code because the kernel and the libraries are 32-bit?

Yes, although it can still use 64-bit instructions and operate on 64-bit data (e.g. dadd, dsub, dmult, ...) normally in N32 mode
Essentially, the 64-bit ABI only enlarges the 'long' and 'pointer' types to 64-bits and thus enables the program to use more than 2GB of RAM.

This document explains the exact differences between N32 and O32 and N64: http://techpubs.sgi.com/library/tpl/cgi-bin/browse.cgi?coll=0650&db=bks&cmd=toc&pth=/SGI_Developer/Mpro_n32_ABI .

That's good to know, if one is going to use posix memory mapping (mmap) with big files.
(on my job I have to deal with satellite images that can be 200GB large).

An Onyx/Origin 3800 system would be more suited to that kind of work if you want to fit the entire dataset within main memory (though an O2 with 1GB of RAM [the maximum for an O2] could map textures up to ~800MB at a time).

henrycault wrote: Oh and another strange behavior, it seems i lose a router link when second test starts... Doesn't seem to affect the system, but it always shuts this link down each time it starts the second test of the run2.sh

After looking at your photo, I don't think you're losing the link - the green LED on the left indicates a successful link, the yellow LED on the right indicates activity <or a fault>. That particular pair of LEDs are associated with node 1 - so it might be possible that node 1 isn't used during the the run2 test.

linkstat or xbstat might give you some additional detail on the router/xbow activity during the test.