High memory usage in 1.7.2 Snapshots

Well, after updating the server to CB 1.7.2 dev build I came across a problem: sudden increasing of RAM usage. During fist 2-5 hours of uptime server works normal, with 3-4G memory usage. But then it starts using a lot more memory than usual - it increases from 3G up to 16G during ~30 seconds, and this causes enormous lags.

For example:

I have a new-generated map on the server, not from older versions (1.6 and lower).
Tried to disable generate-structures option - nothing changed. Tried to fix all chunks on map with the help of Region Fixer - the problem still exists. Tried using VisualVM, make a heap dump and see, what classes overload RAM, here it is:

How it works after start, with 20-30 players online:

What happens next:

Perhaps, something is wrong with DirectByteBuffer and ChannelOutboundBuffer$Entry classes, as you can see in this screenshots.

So, has anybody got the same problem? What should I do to fix this issue? Such enormous memory usage is not OK..

Hope for developers advice..

 

I have the same problem, I randomly jump over 100% of my CPU and all the console says is something about skipping ticks.