Which .net core 5 runtime is preferred x86 or x64?

Tanul 1,251

Team,

Happy NewYear!

On my azure environment, I want to host .net core 5 rest api on this machine

Previous generation A-Series

On this azure machine(part of my service plan) 4 other services are already running where in 1% CPU + 47.44% RAM is already consumed.

Need to add here that I have made this api on my local machine which has 64-bit OS with 8 GB ram.

Which .net core 5 environment should I install as extension in azure app service(32-bit or 64-bit).

Kindly suggest.

Thank you

Accepted answer

Michael Taylor 48,976 Reputation points

2021-01-06T15:00:56.077+00:00

Unless there is a reason not to I'd use x64. Gives you access to more memory if you need it. The cost should be the same as all the Azure App Services are 64-bit processors anyway. Compile your code as Any CPU and it run on either. The only time I'd probably drop down to x86 is if I needed to run software that wasn't supported on x64 (say native C++ code that only had x86 libraries).
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3 people found this answer helpful.
Tanul 1,251 Reputation points

2021-01-06T15:24:09.617+00:00

@Michael Taylor , That is the whole problem. If you check my machine memory which is only 3.5 GB. Now 32-bit allows to use till 3.5 GB only then what is the purpose of x64 .net core runtime at this place.

Michael Taylor 48,976 Reputation points

2021-01-06T16:04:50.977+00:00

You're confusing physical memory with virtual memory. x86 is limited to 2GB of user memory (or 3GB with linker option) and 4GB virtual memory total. x64 is 2TB for Win 10 Pro and higher for server. Running an x64 OS allows you to create apps that use more than 4GB of virtual memory. This is important in apps that need lots of memory like games, databases and web servers. It reduces the likelihood of getting out of memory errors.

Because Windows, like most modern OSes, uses paged memory it can swap virtual memory in and out to allow you to address far more virtual memory than you have physical memory. That is what the page file is for. For example I have 32GB of physical memory on my machine but I have running processes that are using much more than that. My SQL Server instance is at 71GB. Again, no real reason not to use x64. It doesn't matter how much physical memory you have. Of course the more the better performance you get.

Tanul 1,251 Reputation points

2021-01-07T10:20:33.097+00:00

@Michael Taylor , Thanks a lot for the details. Have a great day and happy new year. :)
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1 additional answer

KalyanChanumolu-MSFT 8,316 Reputation points

2021-01-06T14:58:51.64+00:00
@Tanul Thank you for reaching out.
If you are running a 64-bit operating system, you should compile your code for 64-bit and use the 64-bit runtime.

A major benefit of .Net core is that you don't need to install the runtime on your server.
You can bundle it along with your application itself.

Use the below command to generate a self contained app

dotnet publish -r win-x64

Please let us know if you have further questions.
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1 person found this answer helpful.
Tanul 1,251 Reputation points

2021-01-06T15:22:33.147+00:00

@KalyanChanumolu-MSFT , Thank you for the reply. Actually why I'm not preferring self contained because it downloads lot of libraries to my local machine and make a package of around 200 to 300 mb in complete.

Now after downloading everything, it occupies lot of space on my laptop which I cannot clean and those extra libraries for self contained will remain in my laptop. The files download somewhere in the depth of my %userprofile% folders and that's the whole issue why I do not prefer self contained.

Tanul 1,251 Reputation points

2021-01-06T15:25:11.923+00:00

Could you please suggest any specific reason why 64 bit is preferred because my azure machine has only 3.5 GB ram.

KalyanChanumolu-MSFT 8,316 Reputation points

2021-01-07T07:13:27.35+00:00

@Tanul Since @Michael Taylor already answered why you would prefer 64bit, let me clear the confusion you are having about the self contained deployment model.
The files you are referring to are NuGet packages getting downloaded to the cache.
You can easily clear these, read more on that topic here

The entire cache is not included when you publish your app as self contained.
Only the packages referenced within your project are bundled together along with the dotnet framework so that you don't have to depend on runtimes available on the target machine.

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Tanul 1,251 Reputation points

2021-01-07T10:19:48.867+00:00

@KalyanChanumolu-MSFT , Hmm got it. Thanks. Will explore this stuff. Just one last query. I have checked the link you've shared. What are ready to run images. Technically I understood a little but does they only improve the startup speed or over all application performance as well.

KalyanChanumolu-MSFT 8,316 Reputation points

2021-01-07T12:08:55.663+00:00

@Tanul R2R is a form of ahead-of-time (AOT) compilation.
R2R binaries improve startup performance by reducing the amount of work the JIT needs to do as your application is loading.
You will find all the information here

Tanul 1,251 Reputation points

2021-01-07T20:19:02.81+00:00

Thanks a lot for the info. :)
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