Anyone have a good comparison of .net vs java GCs? I never had trouble with the former but Java has been terrible. I'm not sure if its just my project or having the xmx memory cap.
.NET GC Internals mini-series
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Re: .NET GC Internals mini-series
#22Anyone have a good comparison of .net vs java GCs? I never had trouble with the former but Java has been terrible. I'm not sure if its just my project or having the xmx memory cap.
ZGC is the state of the art
Re: .NET GC Internals mini-series
#23How do I know this person really knows about .NET GC internals for me to spend any time watching some videos?
A minimal amount of effort would lead to an author with very good reviews ( 5/5 on amazon)
Re: .NET GC Internals mini-series
#24Please forgive me ignorance, but why can't I manually delete an object? Lots of times I know this one object is pretty big and want to delete it when I am done with it, but have to force the GC to run to clean it up.
Re: .NET GC Internals mini-series
#25Please forgive me ignorance, but why can't I manually delete an object? Lots of times I know this one object is pretty big and want to delete it when I am done with it, but have to force the GC to run to clean it up.
What will deleting it achieve if the GC doesn't run?
Re: .NET GC Internals mini-series
#26Please forgive me ignorance, but why can't I manually delete an object? Lots of times I know this one object is pretty big and want to delete it when I am done with it, but have to force the GC to run to clean it up.
With a GC like the one used in .NET, «deleting» an object is a noop. It wouldn’t give you any benefits over not deleting it.
You only pay a price for living things (as in, some object holding a reference to it), the rest is free.
Re: .NET GC Internals mini-series
#27Please forgive me ignorance, but why can't I manually delete an object? Lots of times I know this one object is pretty big and want to delete it when I am done with it, but have to force the GC to run to clean it up.
Because they're memory objects that are managed by .Net.
If you said "Hey, I'm done with this" that's great, but .Net can't actually delete it until it's checked for itself that nothing else is using it. Otherwise you'll inject an error into the memory manager when you delete an object that's still in use.
So you can kinda fake a delete by releasing the last reference to an object and then forcing a garbage collection (in .Net I think you can call gc.collect() or something)(it's worth noting that the .Net docs specifically said that .Net might ignore your request to do a gc so even calling that is more of a suggestion than a guaranteed garbage collection)
Re: .NET GC Internals mini-series
#28Please forgive me ignorance, but why can't I manually delete an object? Lots of times I know this one object is pretty big and want to delete it when I am done with it, but have to force the GC to run to clean it up.
With a GC like the one used in .NET, «deleting» an object is a noop. It wouldn’t give you any benefits over not deleting it. You only pay a price for living things (as in, some object holding a reference to it), the rest is free.
I guess I could provide a bit more info.
A generational GC as the one in .NET allocates memory up-front, then passes out references/pointers from that allready allocated memory.
When the GC is getting close to the end of the pre-allocated memory, it will analyse all living objects (the objects it can reach from the stack and global variables, and objects referenced by those objects) and copies them over to a different area of memory (generation).
The area the memory was copied from, is now all garbage, and can be overwritten by new objects.
I guess you could say that instead of collecting garbage, it de-fragments your living objects.
If the GC still doesn’t have enough memory, it will try to allocate more.
In any case. The cost of a generational garbage collector is associated with living objects, not dead ones, so manually deleting doesn’t make sense.
Re: .NET GC Internals mini-series
#29Please forgive me ignorance, but why can't I manually delete an object? Lots of times I know this one object is pretty big and want to delete it when I am done with it, but have to force the GC to run to clean it up.
The runtime can't guarantee no use after free if it also allows manual, unchecked free.
Re: .NET GC Internals mini-series
#30Anyone have a good comparison of .net vs java GCs? I never had trouble with the former but Java has been terrible. I'm not sure if its just my project or having the xmx memory cap.
I don't use Java but I was under the impression that it has the most sophisticated gc's available.
Isn't the Shenandoah GC supposed to be able to gc asynchronously without pauses?