javabashgitsvnsubgit

Subgit "Out of Memory" and "GC Overhead Limit Exceeded"

I’m running a conversion project from svn to git. As the application is single threaded, I’m moving the project to a Faster PC.

So without any options bar httpSpooling = true; It runs OK on a VM – 4 CPU's, 20 Gb of Ram.

RAM Usage with two separate instances is 8GB, hitting a max of 9.8Gb.

Jobs Paused, Zipped & SCP'd to new machine – Bare Metal build of Deb9 (same as VM) i7 (8 CPUs(effective)) 16GB ram.

However when starting just one instance of SubGit; I get either Java out of memory or GC Overhead Limit Exceeded. I’ve tried adding the following permutations to repo.git/subgit/config to [daemon]

javaOptions = -noverify -client -Djava.awt.headless=true -Xmx8g -XX:+UseParallelGC -XX:-UseGCOverheadLimit – This gives GC Overhead Limit Exceeded Error
#javaOptions = -noverify -client -Djava.awt.headless=true -Xmx8g -XX:+UseParallelGC -XX:-UseGCOverheadLimit – (OPS Disabled) Gives an out of memory error.
javaOptions = -noverify -client -Djava.awt.headless=true –Xmx12g -XX:-UseGCOverheadLimit – this gives out of memory errors.

I’ve tried other settings too, including changing –client for –server, but that appears to be more two way conversion, which is not something I’m trying to do.

There should be plenty of RAM based on the application usage on a system running successfully, so unless SubGit is ignoring some values, I can’t tell.

Solution

  • The 'javaOptions' in the [daemon] section may indeed be ignored depending on the operation you run: those java options affect SubGit daemon, but not the 'subgit install' or 'subgit fetch' operation. Since you've mentioned that repositories were moved to another machine, I believe, you have invoked either of those two commands to restart the mirror and that's why that 'daemon.javaOptions' is ignored. To tune SubGit's java options edit it right in the SubGit launching script (EXTRA_JVM_ARGUMENTS line):

    EXTRA_JVM_ARGUMENTS="-Dsun.io.useCanonCaches=false -Djava.awt.headless=true -Djna.nosys=true -Dsvnkit.http.methods=Digest,Basic,NTLM,Negotiate -Xmx512m"

    As for the memory consumption itself, it depends on which operations are being run. It's not completely clear how did you pause the jobs on the virtual machine (by 'subgit shutdown' or in another way?), which operations were running at that time (initial translation or regular fetches) and how did you restart the jobs on the new machine.