The upcoming Linux kernel release has functionality for monitoring low level events like cache misses, page faults, instructions and cycles. It may be useful in future development and debugging of the PyPy JIT. The new kernel is expected to be released in about 2 weeks. All relevant links can be found in this article: http://www.h-online.com/open/Kernel-Log-Coming-in-2-6-31-Part-4-Tracing- architecture-virtualisation--/news/114082 Jacob