Java Heap Size

[bastafidli]

Please see

http://forums.sagetv.com/forums/show...9&postcount=19

[gplasky]

Originally Posted by eric3a

I'm getting Java Heap errors about every day also. No time to investigate/debug so I just made a quick dirty .bat file:
net stop "SageTV"
net start "SageTV"

and run it daily at 03:00 in the morning for the time being.

No need for a full reboot to clear the Java Heap. A simple restart of the SageTV service is enough.

Eric

But if this happens everyday it would tend to point to an ill-behaving plugin with a memory leak. You should remove them all and add them back in one at a time to find it.

Gerry

[eric3a]

But if this happens everyday it would tend to point to an ill-behaving plugin with a memory leak. You should remove them all and add them back in one at a time to find it.

Thanks.
Yes, you're probably right but I am running the same plugins I use to run under v6 with no problems so it could be something else also.
I don't have the time or will to investigate at the moment (traveling a lot) so a nightly reset is much easier. I added a log file to the resets and had a look today: The reset takes 7 seconds.
I don't record anything at 03:00am, so it won't be a problem. Plus even if I did, I'd only lose a few seconds of recording. I can live with that for the time being.

Inelegant but it works.

Also I heavily dislike the bare interface, and I find it awkward to navigate and understand compared to my SageMC tailor made one. So a few days of standard UI vs an out of sight reset... I prefer the latter!

I wasn't so much seeking a solution in this thread as adding to the "me too" chorus of people with Java Heap problems.

Eric

[davephan]

What is the maximum JVM heap size?

Before I changed the registry setting my JVM was at 282MB/389MB/389MB (used/total/max) listed in the SageTV system information screen. Before I made the registry setting, the value was set to zero. I changed the value to 200. I then restarted the SageTV service. I checked the JVM size several hours later, it was 259MB/519MB/519MB.

I have 3 gigs RAM in my XP 32-bit system. I plan to have much more memory in my Window 7 64-bit system re-build. What is the maximum size possible for the JVM parameter? I would rather have the parameter set much higher than it might need to be for extra capacity, unless there is a downside to setting the JVM heap size parameter too high.

Dave

[will]

Originally Posted by davephan

I plan to have much more memory in my Window 7 64-bit system re-build. What is the maximum size possible for the JVM parameter?
Dave

I am not sure what the maximum value is but since SageTV is a 32-bit application it will never be able to use more than 2 gigs of ram. When you run it on Windows 7 64-bit, it will run in x86 mode. Software has to be specifically written for a 64-bit system to address more than 2 gigs of ram.

[Nelbert]

Originally Posted by davephan

I have 3 gigs RAM in my XP 32-bit system. I plan to have much more memory in my Window 7 64-bit system re-build. What is the maximum size possible for the JVM parameter? I would rather have the parameter set much higher than it might need to be for extra capacity, unless there is a downside to setting the JVM heap size parameter too high.

Dave

On Windows XP 1.4G-1.6G

In theory the 32 Bit JVM can address upto 4Gb, on Windows 64 bit you might be able to get it as high as 2Gb, but there are no guarentees.

With a bigger heap, the JVM will garbage collect less often as it will wait until either a timer or % full threshold occurs. As there is more memory to garbage collect, it will take longer to garbage collect and could lead to noticable application pauses whilst the garbage collect occurs.

There is no magic value as it all depends what's happening in your jvm and the largest amount of free memory, windows address space, swap etc which will be dictated by your setup. The correct JVM size is a bit trial and error when problems occur rather than use a specific value. I've run systems where limiting the JVM to 1Gb has increases performance in comparison to running the same system with 2Gb and it's all been related to the speed of garbage collection.

Sun/Oracle FAQ

[sacrament055]

I believe the number mentioned in a previous post is correct 1.5 GB is the max. I tried using 2 GB once and Sage wouldn't start with that setting. Once I moved it back down to 1.5 it started working again.

[Nelbert]

From a dos prompt you should be able to do something like

"java -xms1.5G -version"

Once you reach the limit of the JVM or the system you'll get an error along the lines of

"Error occurred during initialization of VM
Could not reserve enough space for object heap"

ie not enough contiguous free memory for the requested size.

Using -Xms will try and allocate the memory immediately as that is the starting heap size. I can't remember whether win32 lets you allocate out of swap but obviously if you create a jvm that needs to use swap you'll hose the performance. ie 1.5G jvm on a 1G machine is a waste of time.

The Win64 machine I'm using atm it seems to die at -Xms5G with a 64bit jvm and it only has 2.3G of actual ram free. Don't use -Xmx for testing the max size you can use though. I've just allocated 60G to Xmx and it hasn't errorred. 58G of that will be in the Windows swap file. 61G was just too much and it threw an out of swap space error.

[mayamaniac]

I switched to Win7 64 bit recently and went to change the java heap size, but the location of it is different than in 32bit. It is located in:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Frey Technologies\Sage TV\JVMMaxHeapSizeMB