New product are coming

[Taddeusz]

Maybe my expectations about how a program should run don't match with how the JVM operates. I'm a C# developer and don't feel like I need to know the nuts and bolts of the CLR to write an efficient application. While my C# programs are running I don't see the constant ballooning I see with Java. But that may be because Microsoft hides that part of the CLR. Or I don't know where to look. My C# applications always seem to use very little memory.

[EnterNoEscape]

Originally Posted by Taddeusz

Maybe my expectations about how a program should run don't match with how the JVM operates. I'm a C# developer and don't feel like I need to know the nuts and bolts of the CLR to write an efficient application. While my C# programs are running I don't see the constant ballooning I see with Java. But that may be because Microsoft hides that part of the CLR. Or I don't know where to look. My C# applications always seem to use very little memory.

I wrote a program that broadcasted high resolution images with data on them (like time, weather and BeyondTV recordings) to a network of picture frames in my house in C#. The time I did this was when I was kind of a new to C#, but I learned quickly that I couldn't just let it go and do it's thing. I would run out of memory very fast even though I wasn't creating objects too large to fit in memory collectively and I was releasing all of the objects as soon as they were no longer needed. My remediation was to force it to happen between images and the problem went away. I never actually went back to figure out exactly what the problem was as I no longer use it. The take away is that even C# may give you a reason to find out why the CLR works the way it does.


I have a brief comment about the OOM issues mentioned. I have seen SageTV under VisualJVM. It's mostly char[] and byte[] arrays due to the database. I personally didn't notice anything odd when I was profiling for several weeks to get Carny working as fast as I could get it. Granted I wasn't looking at much along the lines of native memory consumption which is used a lot by SageTV for graphics, but at least within the heap, nothing appeared to be accumulating without governance.

[Taddeusz]

Originally Posted by EnterNoEscape

I wrote a program that broadcasted high resolution images with data on them (like time, weather and BeyondTV recordings) to a network of picture frames in my house in C#. The time I did this was when I was kind of a new to C#, but I learned quickly that I couldn't just let it go and do it's thing. I would run out of memory very fast even though I wasn't creating objects too large to fit in memory collectively and I was releasing all of the objects as soon as they were no longer needed. My remediation was to force it to happen between images and the problem went away. I never actually went back to figure out exactly what the problem was as I no longer use it. The take away is that even C# may give you a reason to find out why the CLR works the way it does.


I have a brief comment about the OOM issues mentioned. I have seen SageTV under VisualJVM. It's mostly char[] and byte[] arrays due to the database. I personally didn't notice anything odd when I was profiling for several weeks to get Carny working as fast as I could get it. Granted I wasn't looking at much along the lines of native memory consumption which is used a lot by SageTV for graphics, but at least within the heap, nothing appeared to be accumulating without governance.

Yeah, with C# and likely other .NET languages you do have to pay attention to if an object needs to be "closed" before it goes out of scope. "Using" statements as well as try/catch/finally are really handy for dealing with that.

I've been reading up on the differences between JVM and CLR as far as memory use is concerned. The main takeaway that I learned is that depending on the GC being used JVM is ultra-conservative about releasing memory back to the system while CLR is really aggressive by comparison.

That explains what I see with Java memory use. I still don't understand why a seemingly idle process would continue to create hundreds of MB of objects that need GC and produces the "healthy" sawtooth memory use pattern.