I have tried running this on an intel arch and amd64 arch machine and found it does leak over time.
We have a severe memory leak issue that appears to be related to detached threads in some of our code.
Running the 5.8.8
Your test when run on amd64 platform took 36M after 10 minutes we're upto 63M and rising....
My laptop running Ubuntu feisty (i386) leaked at a slower rate...
Yours,
Karl Royer