> Thomas Wouters asked if he had looked at PyPy. Shapiro said the company had, but there was only a modest bump in performance for its workload. He was not the one who did the work, however. Wouters noted that PyPy is more than "Python with a JIT" because it has its own data model as well.

This is interesting. How much was a "modest bump" in performance ? And why was the bump in performance not a reason for adoption ? Does Pypy break a lot of stuff ?

Oh and this

> Some of what Shapiro presented did not sit well with Guido van Rossum, who loudly objected to Shapiro's tone, which was condescending, he said. Van Rossum thought that Shapiro did not really mean to be condescending, but that was how he came across and it was not appreciated. The presentation made it sound like Shapiro and his colleagues were the first to think about these issues and to recognize the inefficiencies, but that is not the case. Shapiro was momentarily flustered by the outburst and its vehemence, but got back on track fairly quickly.

> Shapiro's overall point was that he felt Python sacrificed its performance for flexibility and generality, but the dynamic features are typically not used heavily in performance-sensitive production workloads. So he believes it makes sense to optimize for the common case at the expense of the less-common cases. But Shapiro may not be aware that the Python core developers have often preferred simpler, more understandable code that is easier to read and follow, over more complex algorithms and data structures in the interpreter. Some performance may well have been sacrificed for readability.