I have three DDR PC 3200 memory modules, two of which are 512 MB and one of which is 1 GB. My motherboard manual describes 1-, 2-, and 4-modules configurations; is it okay to install three?
If you're not using dual channel memory configurations it should work. Only way to know is to try it and see.
This is not a programming question, BTW and will be closed very shortly.
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I am new to the RAPIDS AI world and I decided to try CUML and CUDF out for the first time.
I am running UBUNTU 18.04 on WSL 2. My main OS is Windows 11. I have a 64 GB RAM and a laptop RTX 3060 6 GB GPU.
At the time I am writing this post, I am running a TSNE fitting calculation over a CUDF dataframe composed by approximately 26 thousand values, stored in 7 columns (all the values are numerical or binary ones, since the categorical ones have been one hot encoded).
While classifiers like LogisticRegression or SVM were really fast, TSNE seems taking a while to output results (it's been more than a hour now, and it is still going on even if the Dataframe is not so big). The task manager is telling me that 100% of GPU is being used for the calculations even if, by running "nvidia-smi" on the windows powershell, the command returns that only 1.94 GB out of a total of 6 GB are currently in use. This seems odd to me since I read papers on RAPIDS AI's TSNE algorithm being 20x faster than the standard scikit-learn one.
I wonder if there is a way of increasing the percentage of dedicated GPU memory to perform faster computations or if it is just an issue related to WSL 2 (probably it limits the GPU usage at just 2 GB).
Any suggestion or thoughts?
Many thanks
The task manager is telling me that 100% of GPU is being used for the calculations
I'm not sure if the Windows Task Manager will be able to tell you of GPU throughput that is being achieved for computations.
"nvidia-smi" on the windows powershell, the command returns that only 1.94 GB out of a total of 6 GB are currently in use
Memory utilisation is a different calculation than GPU throughput. Any GPU application will only use as much memory as is requested, and there is no correlation between higher memory usage and higher throughput, unless the application specifically mentions a way that it can achieve higher throughput by using more memory (for example, a different algorithm for the same computation may use more memory).
TSNE seems taking a while to output results (it's been more than a hour now, and it is still going on even if the Dataframe is not so big).
This definitely seems odd, and not the expected behavior for a small dataset. What version of cuML are you using, and what is your method argument for the fit task? Could you also open an issue at www.github.com/rapidsai/cuml/issues with a way to access your dataset so the issue can be reproduced?
Please help me understand this :
If my machine has a Ram (Physical memory) of 2 GB , Will I still have a Virtual address space of 4 GB in a 32 bit machine ?
I have read somewhere that a 32 bit application has a max limit of 2 GB virtual address space.
If I have a total of 4 GB VAS , 1 GB is used by OS . So 3 GB is remaining for the applications to use . If I have 2 applications running both using 2 GB of memory ,I want to know if they will work since we are left with only 3GB .Is this where paging comes to picture?
On a 32-bit installation, by default, only 2 GB is made available to processes for their own use. The other 2GB are used by the operating system. On later 32-bit editions of Microsoft Windows it is possible to extend the user-mode virtual address space to 3 GiB while only 1 GiB is left for kernel-mode virtual address space by marking the programs as IMAGE_FILE_LARGE_ADDRESS_AWARE and enabling the /3GB switch in the boot.ini file.
If you wanted to run two applications each with 2GB of memory, you will run into a memory exception when either application tries to use the memory that has already been absorbed but the OS.
I got the clarification here:
http://social.msdn.microsoft.com/Forums/windowsdesktop/en-US/8d63585e-772d-42e5-a40a-72a9500ac0a7/understanding-on-32-bit-environment-application?forum=windowsgeneraldevelopmentissues#8d63585e-772d-42e5-a40a-72a9500ac0a7
Given a 2 processor Nehalem Xeon server with 12GB of RAM (6x2GB), how are memory addresses mapped onto the physical memory modules?
I would imagine that on a single processor Nehalem with 3 identical memory modules, the address space would be striped over the modules to give better memory bandwidth. But with what kind of stripe size? And how does the second processor (+memory) change that picture?
Intel is not very clear on that, you have to dig into their hardcore technical documentation to find out all the details. Here's my understanding. Each processor has an integrated memory controller. Some Nehalems have triple-channel controllers, some have dual-channel controllers. Each memory module is assigned to one of the processors. Triple channel means that accesses are interleaved across three banks of modules, dual channel = two banks.
The specific interleaving pattern is configurable to some extent, but, given their design, it's almost inevitable that you'll end up with 64 to 256 byte stripes.
If one of the processors wants to access memory that's attached to the IMC of some other processor, the access goes through both processor and incurs additional latency.
I plan to run 32-bit Windows XP on a workstation with dual processors, based on Intel's Nehalem microarchitecture, and triple channel RAM. Even though XP is limited to 4 GB of RAM, my understanding is that it will function with more than 4 GB installed, but will only expose 4 GB (or slightly less).
My question is: Assuming that 6 GB of RAM is installed in six 1 GB modules, which physical 4 GB will Windows actually map into its address space?
In particular:
Will it use all six 1 GB modules, taking advantage of all memory channels? (My guess is yes, and that the mapping to individual modules within a group happens in hardware.)
Will it map 2 GB of address space to each of the two NUMA nodes (as each processor has it's own memory interface), or will one processor get fast access to 3 GB of RAM, while the other only has 1 GB?
Thanks!
This question was answered over at SuperUser. Because there are no other responses here, I'm responding to my own question so that the relevant information can easily be found.
Since the question was asked, I have also come across this blog post by Mark Russinovich, explaining how the Windows XP kernel handles memory.
In conclusion, it appears that what happens is that the kernel, even though it is PAE aware, truncates all physical memory addresses to 32-bit, meaning only the lowest physical 4 GB of RAM will be used. This in turn is mapped by hardware to memory modules, and corresponds to the entirety of the first module triplet (3 GB in total), and a third of the second triplet (spread across all three of its modules -- 1 GB in total).
Thus, all memory channels will be exploited, but the amount of memory will not be balanced between NUMA nodes.
Jeff covered this a while back on his blog in terms of 32 bit Vista.
Does the same 32 bit 4 GB memory cap that applies in 32 bit Vista apply to 32 bit Ubuntu? Are there any 32 bit operating systems that have creatively solved this problem?
Ubuntu server has PAE enabled in the kernel, the desktop version does not have this feature enabled by default.
This explains, by the way, why Ubuntu server does not work in some hardware emulators whereas the desktop edition does
Well, with windows, there's something called PAE, which means you can access up to 64 GB of memory on a windows machine. The downside is that most apps don't support actually using more than 4 GB of RAM. Only a small number of apps, like SQL Server are programmed to actually take advantage of all the extra memory.
Yes, 32 bit ubuntu has the same memory limitations.
There are exceptions to the 4GB limitation, but they are application specific... As in, Microsoft Sql Server can use 16 gigabytes with "Physical address Extensions" [PAE] configured and supported and... ugh
http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=3703755&SiteID=17
Also drivers in ubuntu and windows both reduce the amount of memory available from the 4GB address space by mapping memory from that 4GB to devices. Graphics cards are particularly bad at this, your 256MB graphics card is using up at least 256MB of your address space...
If you can [your drivers support it, and cpu is new enough] install a 64 bit os. Your 32 bit applications and games will run fine.
There seems to be some confusion around PAE. PAE is "Page Address Extension", and is by no means a Windows feature. It is a hack Intel put in their Pentium II (and newer) chips to allow machines to access 64GB of memory. On Windows, applications need to support PAE explicitely, but in the open source world, packages can be compiled and optimized to your liking. The packages that could use more than 4GB of memory on Ubuntu (and other Linux distro's) are compiled with PAE support. This includes all server-specific software.
In theory, all 32-bit OSes have that problem. You have 32 bits to do addressing.
2^32 bits / 2^10 (bits per kb) / 2^10 (kb per mb) / 2^10 (mb per gb) = 2^2 = 4gb.
Although there are some ways around it. (Look up the jump from 16-bit computing to 32-bit computing. They hit the same problem.)
Linux supports a technology called PAE that lets you use more than 4GB of memory, however I don't know whether Ubuntu has it on by default. You may need to compile a new kernel.
Edit: Some threads on the Ubuntu forums suggest that the server kernel has PAE on by default, you could try installing that.