Beginner here.
cpu says > 4GB, OS tells <4GB.
What is the answer?
I saw in windows, it is 2.8GB, in linux i think it can access complete 4GB
Related
The issue that I experience is that when running simulations (same IBPSA/AixLib-based models) on Linux I get a significant performance drop (simulation time is about doubled) in comparison to a Windows 8 machine. Below you find the individual specs of the two machines. In both cases I use Cvode solver with equal settings. Compilation is done with VC14.0 (Win) or GCC (Xubuntu).
Is this issue familiar to someone or can anyone help what the reason might be?
Win 8:
Intel Xeon #2.9GHz (6 logic processors)
32 GB RAM
64-Bit
Xubuntu 16.04 VM:
Intel Xeon #3.7GHz (24 logic processors)
64 GB RAM
64-Bit
Thanks!
In addition to the checklist in the comments, also consider enabling hardware virtualization support if not already done.
In general gcc tends to produce slower code than Visual Studio. In order to turn on optimization one could try adding the following line:
CFLAGS=$CFLAGS" -02"
at the top of insert/dsbuild.sh.
The reason for not having it turned on by default is to avoid lenghty compilations and bloated binaries. For industrial sized models these are actual issues.
Will there be a difference in the performance of a 32 bit operating system running on 64 bit processor and a 32 bit operating system running on 32 bit processor?
Just realized this didn't specify x86. I don't know if any ARMv8 CPUs are slower in ARMv7 mode than a similar-cost ARMv7 CPU.
You can't really compare apples-to-apples, because there's no such thing as a 64-bit CPU that's exactly the same as a 32-bit CPU except for supporting 64-bit mode. There are always other microarchitectural changes, too. (Like from Pentium M to Core2 on Intel.)
If we're talking about x86, then no. A 64-bit capable x86 CPU is no worse at running 32-bit code. This is called "legacy mode", as opposed to "compat mode" (32-bit user-space under 64-bit OS), but they perform the same.
In fact, the only CPUs that can't run in x86-64 mode these days are old, slow, or both. e.g. using a 32-bit-only CPU means you're running on Pentium4, Pentium-M, or an old Atom! Or Athlon-XP. Or an embedded x86 like Geode.
This is the same reason that 32-bit software is still widely used under Windows (although usually under a 64-bit OS).
The option you didn't mention is the high-performance one: 64-bit OS on a 64-bit CPU, even if you want to run 32-bit user-space code.
Especially if you have more than 1 or 2GB of RAM, it's likely that your system will run faster with a 64-bit kernel. 32-bit kernels can use more RAM, but it's ugly and not as fast as if the kernel can have all physical memory mapped into kernel-space virtual memory. See Linus Torvald's comments on PAE (Physical-Address Extensions)
See the x86 tag wiki for more about how x86 CPUs perform, and how to optimize for them.
Yes because you wouldn't make full use of all those 64bits. If you have a 32bits OS than you will only use that and not 64. However, if you were to have 64bits OS than it will make full use of those bits.
Also, please have a look at:
https://www.howtogeek.com/194119/why-are-most-programs-still-32-bit-on-a-64-bit-version-of-windows/
and
http://www.osnews.com/story/5768
All the info I can find basically says the 64 bit version is available but I can't find any info on what exactly that means? How is it different from the 32bit version?
From the release notes:
Large file support - Improved performance for large files, no size limit on 64-bit machines.
64-bit Windows builds - Use your computer's full address space with the 64-bit builds.
For example, to open large files (the 32 bit version has now a limit of 300 MB, previously it was 50 MB) you'll need the 64 bit version.
On Windows10 64 bit & Netbeans 8.2 the Netbeans IDE shows about 218 MB memory consumption but in Windows Task manager it shows about 527 MB!
Is there any explanation for that, specillay the performance of the system is lost!
RAM != Java heap space. Here is an article trying to explain the difference between memory usage and heap space usage. Hope this helps.
Is there any way to write code for the Quark CPU on the Intel Edison and establish a communication between the Quark CPU, which is - as far as i know - running an RTOS, and the Atom CPU, which is running Yocto.
I've googled for some tutorials but didn't find any.
Thank you guys!
According to several postings in the Intel forum it is not supported at this time