8. Performance Internals

Interpreter dispatch, inline caches, the specializing adaptive interpreter, function call fast paths, vectorcall, dictionary and attribute access performance, memory locality, profiling, and benchmarking.

10 items

Chapter Title
72 Interpreter Dispatch
73 Inline Caches
74 Specializing Adaptive Interpreter
75 Function Call Fast Paths
76 Vectorcall
77 Dictionary Performance
78 Attribute Access Performance
79 Memory Locality
80 Profiling CPython
81 Benchmarking CPython
Deep Reads › CPython Internals › 8. Performance Internals ›

72. Interpreter Dispatch

Computed goto dispatch table, the switch fallback, and how opcode prediction reduces branch mispredictions.
cpython python internals performance
Deep Reads › CPython Internals › 8. Performance Internals ›

73. Inline Caches

Inline cache entries appended to CACHE instructions in the bytecode array and their layout per opcode family.
cpython python internals performance
Deep Reads › CPython Internals › 8. Performance Internals ›

74. Specializing Adaptive Interpreter

Adaptive counter logic, specialization guards, and how CPython 3.11+ rewrites opcodes to LOAD_ATTR_SLOT and friends.
cpython python internals performance
Deep Reads › CPython Internals › 8. Performance Internals ›

75. Function Call Fast Paths

CALL_PY_EXACT_ARGS, CALL_BUILTIN_FAST, and the fast-path conditions that bypass the generic call machinery.
cpython python internals performance
Deep Reads › CPython Internals › 8. Performance Internals ›

76. Vectorcall

PEP 590 vectorcall protocol, _Py_TPFLAGS_HAVE_VECTORCALL, and stack-based argument passing for zero-overhead calls.
cpython python internals performance
Deep Reads › CPython Internals › 8. Performance Internals ›

77. Dictionary Performance

Compact dict memory layout, hash collision probing strategy, split-table sharing, and lookup specialization.
cpython python internals performance
Deep Reads › CPython Internals › 8. Performance Internals ›

78. Attribute Access Performance

Type version tags, LOAD_ATTR inline cache hits, and the attribute specialization guards for slots and descriptors.
cpython python internals performance
Deep Reads › CPython Internals › 8. Performance Internals ›

79. Memory Locality

Object allocation locality, arena page placement, freelists for common types, and cache-line–aware design.
cpython python internals performance memory
Deep Reads › CPython Internals › 8. Performance Internals ›

80. Profiling CPython

Using perf, Instruments, and py-spy to profile CPython; reading perf maps generated by the JIT.
cpython python internals performance
Deep Reads › CPython Internals › 8. Performance Internals ›

81. Benchmarking CPython

pyperformance benchmark suite, microbenchmark pitfalls, timer resolution, and interpreter warm-up effects.
cpython python internals performance