How reflection changes will make your apps faster in .NET 7

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Hello everybody I'm Nick and in this video I will show you the updates that reflection got in .NET 7 that make it perform up to 4 times faster in some scenarios.
The pull request: github.com/dotnet/runtime/pul...
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#csharp #dotnet #reflection

[@conbag5736]

Interesting. I believe that Blazor uses Reflection pretty heavily. I'm guilty of making my interfaces very modular - creating lots of small reusable components. However, they say that you should try limit your use of Components because each time they are rendered, reflection is used under the hood to set the values of component parameters. In theory, this should be very good news for me, and Blazor in general.

[@figloalds]

Nice to see this getting a boost, it will definitely improve my micro-orm construction time, so I assume it will also improve all ORMS and mappers in general across the board too, which is NEAT

[@willinton06]

It’s NET

[@diadetediotedio6918]

Why not using source generators for your ORM and remove the reflection dependency?

[@figloalds]

@@diadetediotedio6918 I don't like it, it's one of the core reasons I moved away from Entity Framework and decided to make my own micro-orm

[@jradplowman]

Your easter eggs are so good and so subtle! Love it 😀

[@kaiserbergin]

Wow this is super helpful for one of my projects. It uses a lot of reflection with ctors and this is very exciting. Thanks for sharing!

[@MicroLosi]

Usually I stop videos from other authors when patreons list appear. But in this case - I wait all way throught the list to hear this magic "keep coding" ))))

[@nothingisreal6345]

Thanks for the update and video. Very important improvement indeed. Many libraries use creating instances by type names. IMHO calling methods via reflection is maybe less frequently used.

[@krccmsitp2884]

Very nice, thanks for showing!

[@williamliu8985]

cool, really like the performance improvement bring in reflection and generic area!

[@Anequit]

Very impressed! Good job .net team

[@angelgabrielvaldessarduy7566]

This is amazing. Thanks!👽

[@nitrous1001]

Working on a project that makes use of LINQ Expression. Although I do need to use reflection initially for caching purposes. This is quite a benefit.

[@gunnarliljas8459]

Indeed. I expect that to be a good way, even after .NET 7 arrives, whenever the methods are reused a lot. The performance benefits can be massive. In the example given, the improvement over plain reflection was 25-200x. Yes, times. Quite often it can also be further improved by using FastExpressionCompiler (Nuget)

[@TonoNamnum]

thanks for the great video! it's rare to change a private variable. there are a lot of cases when the dynamic keyword could substitute reflection. I wonder how will this compare with performance.

[@pqsk]

Amazing stuff.

[@lalibi]

Hey Nick, did you have the chance to benchmark the built-in DI, with the latest preview? Does it benefit from those improvements?

[@davidwilliss5555]

I'd like to see benchmarks on PropertyInfo reflection. I use that a LOT and it would be nice to speed that up

[@gunnarliljas8459]

It should be similar, since properties are just methods. If you set the same properties often, you should probably build a Func or an Action, using LINQ expressions.

[@antonmartyniuk]

Great news!

[@protox4]

Interesting, but does that performance improvement also exist in AOT? IL emitting typically doesn't work in AOT. I'm still waiting for the fast reflection (new APIs) to make it into the runtime (the issue was put on future roadmap, unfortunately).

[@shingok]

That will help to clean a lot of code that is using lambda expressions and il emit for performance reasons

[@mjuniorjr5942]

Hey Nick! I appreciate all your youtube work. Can I ask something? Can you please make a video or video series about all about authentication with database. With and with your own authentication handler, cookies and jwt, with middleware and with your own middleware, what's claims, identity, principal, security context, roles, how we store these in database, how we receive principal from frontend, why they need call AddAuthentication and then call AddCookies for example. Why we need Identity, what's oauth, what's identity server, what's mfa, external providers and why all of this stuffs are different and what's is different in web api, blazor, mvc, and in all .net template. And how this get evolved. It's very confused for me, and I think there's so many people that thinks confused about authentication as well. Thanks!!!

[@ahmedmedo7642]

Hi, i want to begin learning about .net and i want an advice about how to begin from which version and what book do you recommend to begin with as a beginner

[@Brodeon]

Can you benchmark yarp and compare it to for example nginx? I am quite curious how YARP is fast. Since nginx is written in C we can of course assume nginx will be faster but how much faster than yarp

[@danielschmid8530]

Neeto, I just installed the Visual Studio preview to try out Maui and if this monster benefits of something it's reflection. Same for XAML in WPF oh lord I might just pick that one up again for funsies as well.

[@baracek8797]

I once had a 3rd party library of proprietary closed source code that had a memory corruption issue. The company refused to believe it a problem even when I sent them the decompiled code with the problem in it and pointed out the line that needed changing. I used reflection to get the field that had the problem and pin it so that it wasn't moved by the GC when unmanaged code had a pointer to it. That is the only case where I thought reflection of private members was necessary and warranted.

[@alexisfibonacci]

Hmmm...

[@meydanozeri4322]

I'm curious on what would be faster, manually emitting IL myself or using the improved reflection of .NET 7. Maybe you should have tested that as well

[@sealsharp]

Sweet.

[@MrRobin4444]

nice, almost missed the improvement. it would be interesting how that improves enums. (since they are almost entirely reflection based) *Wouldn't null instead of an empty array be even faster?

[@vm123]

I did some testing by my own and found out that getting property value by reflection in loop is way faster than compiling expression on the fly (to lambda func). At about a million loop size expression compiling solution catches up the reflection based solution times. Is is possible or my test method could be flawed?

[@alexgriffith5161]

my irc bot library uses a lot of reflection this is good news for me

[@dadcraft9949]

I happened to be working on something in this area just now and I'm curious how the performance of the emitted IL compares to cached delegate performance. The delegate approach is certainly much faster than calling the get method directly via reflection, if you're making enough invocations to account for the overhead of constructing the delegate. To illustrate what I mean, calling these delegates achieves the same performance as calling a virtual method, which is significantly faster than calling Invoke directly on the MethodInfo (at least before .NET 7...) var getterDelegateType = typeof(Func).MakeGenericType(propertyOwnerType, propertyInfo.PropertyType); var setterDelegateType = typeof(Action).MakeGenericType(propertyOwnerType, propertyInfo.PropertyType); var getterDelegate = propertyInfo.GetGetMethod().CreateDelegate(getterDelegateType); var setterDelegate = propertyInfo.GetSetMethod().CreateDelegate(setterDelegateType);

[@DJosh-cs5vx]

Thanks

[@_Aarius_]

I'm working on a personal project that relies on reflection a lot, so any performance improvements are always welcome to me.

[@TheMonk72]

Now do a Linq Expression version. Create an action to call the set method compile it and see how fast the call is. It surprised me.

[@adamponka6404]

I'm dissapointed you didn't compare it with CreateDelegate method cause that's the one most heavily used for reflection optimization. Do we still need it or is Invoke optimized enough to forget about it

[@nickchapsas]

If I remember correctly CreateDelegate cant replace all reflection calls. It can replace the PropertyInfo ones and I have a video on that but I’m not so sure on MethodInfo and ConstructorInfo

[@tarsala1995]

Hi Nick, just want to inform you that new StackOverflow survey results came out. You might want to have some commentary on that :)

[@marcelofernandes8005]

Hey Nick. Really enjoy your content. Especially the benchmark stuff. I was curious if the Activator.CreateInstance also has any performance improvements in .Net7? Since it is usually the fastest way to create an instance with an empty constructor, but trails being the GetConstructorInfo method when the constructor has parameters....

[@nickchapsas]

I actually haven’t investigated this one. Will need to take a look

[@onyxgc2568]

I used to cached the object properties to make reflection run faster.

[@brianm1864]

All of these great new features/enhancements in .NET 7 are making me sad, as we will probably skip 7 and wait for 8

[@sergeybenzenko6629]

Which is the right choise for production code, because .NET 7 is not LTS version.

[@BillyBraga]

Well, if you can afford the slight man power to upgrade from 7 and 8, it's alright. Non-LTS are not less stable or reliable, only supported for a shorter time.

[@sanampakuwal]

​@@BillyBraga agree with you

[@brianm1864]

@@BillyBraga Unfortunately it is a manpower issue. Too much to do, too little time.

[@sanampakuwal]

@@brianm1864 update from dotnet 6 to 7 is not a big task (you could only argue about manpower if the case was to migrate dotnet framework 4.8 to dotnet 7 btw) at least if the solution is less than ~50 projects

[@PetrVejchoda]

Is the GetAge allocating because of the Array.Empty method? I would hope it is internally cached.

[@nickchapsas]

No it is internally cached

[@PetrVejchoda]

@@nickchapsas umm, I still can't get over why GetAge is allocating whilst the SetAge is not. Is that like the first time use allocation and then it is cached? I don't see why those two method infos should behave differently. Maybe I am just missing something. I am sorry, I am too lazy to recreate it and investigate that myself, I just wanted to ask if somebody knows out of the box.

[@nickchapsas]

@@PetrVejchoda Set age is allocating because it is boxing the value type in the object array

[@julienc.8562]

I wonder how it compares to Fastmember

[@raingelfer]

Nick, I 'm pretty sure, you may pass a target dotnet version directly into benchmarks.

[@nickchapsas]

You can but I couldn't find the .NET 7 support yet

[@possessedllama]

If someone is using reflection to access a private class or member in another library, I'd suggest they write a wrapper around it and unit test the wrapper extensively.

[@liontalha7383]

Anyone have any idea how to add watermark to each page of doc or pdf file and how to add a text file in zipped file and zip again. Any reference will be useful

[@corinnarust]

I'm a Java developer. *Proceeds to the next video*

[@IgnoreSolutions]

Unity: *sweats excitedly*

[@enfy1337]

unfortunately it'll be at least 2 more years until unity supports .NET 7

[@mariocamspam72]

Unity uses Mono + il2cpp for C#, not .NET

[@IgnoreSolutions]

@@mariocamspam72 Don’t you think the Mono folks will see this and follow suit? Bit pedantic

[@mariocamspam72]

@@IgnoreSolutions Can Mono just copy the implementation from .NET runtime though? Wouldn't it be a licensing nightmare?

[@IgnoreSolutions]

@@mariocamspam72 No…..but they can implement in the runtime like Microsoft is for .NET. If .NET 7 spec states that these changes should be made to reflection, then Mono will have to implement them to maintain compatibility.

[@MrKyriotetes1]

Do become Nick patreon can get more video?

[@igorthelight]

You can see all unavailable videos (blurred) BEFORE subscribing to a someone's Patreon ;-)

[@aj.arunkumar]

mic drop*

[@justwatching6118]

I knew there will be 69 with age :D :D