tests of "why" against WHY_YIELD became useless. This patch removes them,
but assert()s that why != WHY_YIELD everywhere such a test was removed.
The test suite ran fine under a debug build (i.e., the asserts never
triggered).
* Defer error handling for wrong number of arguments to the
unpack_iterable() function. Cuts the code size almost in half.
* Replace function calls to PyList_Size() and PyTuple_Size() with
their smaller and faster macro counterparts.
* Move the constant structure references outside of the inner loops.
(Contributed by Andrew I MacIntyre.)
disables opcode prediction when dynamic execution
profiling is in effect, so the profiling counters at
the top of the main interpreter loop in eval_frame()
are updated for each opcode.
Simplified version of Neal Norwitz's patch which adds gotos for
opcodes that set "why". This skips a number of tests where the
outcome of the tests are known in advance.
A new API (only accessible from C) to interrupt a thread by sending it
an exception. This is not always effective, but might help some people.
Requested by Just van Rossum and Alex Martelli. It is intentional
that you have to write your own C extension to call it from Python.
Docs will have to wait.
* Can now test for basic blocks.
* Optimize inverted comparisions.
* Optimize unary_not followed by a conditional jump.
* Added a new opcode, NOP, to keep code size constant.
* Applied NOP to previous transformations where appropriate.
Note, the NOP would not be necessary if other functions were
added to re-target jump addresses and update the co_lnotab mapping.
That would yield slightly faster and cleaner bytecode at the
expense of optimizer simplicity and of keeping it decoupled
from the line-numbering structure.
Added two predictions:
GET_ITER --> FOR_ITER
FOR_ITER --> STORE_FAST or UNPACK_SEQUENCE
Improves timings on pybench and timeit.py. Pystone results are neutral.
Applied to common cases:
COMPARE_OP is often followed by a JUMP_IF.
JUMP_IF is usually followed by POP_TOP.
Shows improved timings on PyStone, PyBench, and specific tests
using timeit.py:
python timeit.py -s "x=1" "if x==1: pass"
python timeit.py -s "x=1" "if x==2: pass"
python timeit.py -s "x=1" "if x: pass"
python timeit.py -s "x=100" "while x!=1: x-=1"
Potential future candidates:
GET_ITER predicts FOR_ITER
FOR_ITER predicts STORE_FAST or UNPACK_SEQUENCE
Also, applied missing goto fast_next_opcode to DUP_TOPX.
My previous patches should have used fast_next_opcode
in a few places instead of continue.
Also, applied one PyInt_AS_LONG macro in a place where
the type had already been checked.
-DCALL_PROFILE: Count the number of function calls executed.
When this symbol is defined, the ceval mainloop and helper functions
count the number of function calls made. It keeps detailed statistics
about what kind of object was called and whether the call hit any of
the special fast paths in the code.
Optimization:
When we take the fast_function() path, which seems to be taken for
most function calls, and there is minimal frame setup to do, avoid
call PyEval_EvalCodeEx(). The eval code ex function does a lot of
work to handle keywords args and star args, free variables,
generators, etc. The inlined version simply allocates the frame and
copies the arguments values into the frame.
The optimization gets a little help from compile.c which adds a
CO_NOFREE flag to code objects that don't have free variables or cell
variables. This change allows fast_function() to get into the fast
path with fewer tests.
I measure a couple of percent speedup in pystone with this change, but
there's surely more that can be done.
Make the code slightly shorter, faster, and easier to
read.
* Eliminate unused DUP_TOPX code for x==1.
compile.c always generates DUP_TOP instead.
* Since only two cases remain for DUP_TOPX, replace
the switch-case with if-elseif.
* The in-lined integer compare does a CheckExact on
both arguments. Since the second is a little more
likely to fail, test it first.
* The switch-case for IS/IS_NOT and IN/NOT_IN can
separate the regular and inverted cases with no
additional work. For all four paths, saves a test and
jump.
The two are semantically equivalent, but the first triggered a compiler
warning about an unused variable. Note, the preceding steps had already
accessed and decreffed the variable so the reference counts were fine.
parameter being either four or five. Currently, compile.c does not
generate calls with a parameter higher than three.
May have to be reverted if the second alpha or beta shakes out some
other tool generating this op code with a parameter of four or five.
Replaced groups of pushes and pops with indexed access to the stack and
a single adjustment (if needed) to the stacklevel.
Avoids scores of unnecessary increments and decrements to the stackpointer.
Removes unnecessary sequential dependencies so that the compiler has more
freedom for optimizations. Frees the processor for more parallel and
pipelined execution by using mostly read-only access and having few pointer
adjustments just prior to a read or write.
