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-rw-r--r--Python/optimizer.c20
-rw-r--r--Python/specialize.c1
2 files changed, 18 insertions, 3 deletions
diff --git a/Python/optimizer.c b/Python/optimizer.c
index 7c46bd6..d44e733 100644
--- a/Python/optimizer.c
+++ b/Python/optimizer.c
@@ -409,6 +409,9 @@ BRANCH_TO_GUARD[4][2] = {
#define TRACE_STACK_SIZE 5
+#define CONFIDENCE_RANGE 1000
+#define CONFIDENCE_CUTOFF 333
+
/* Returns 1 on success,
* 0 if it failed to produce a worthwhile trace,
* and -1 on an error.
@@ -431,6 +434,7 @@ translate_bytecode_to_trace(
_Py_CODEUNIT *instr;
} trace_stack[TRACE_STACK_SIZE];
int trace_stack_depth = 0;
+ int confidence = CONFIDENCE_RANGE; // Adjusted by branch instructions
#ifdef Py_DEBUG
char *python_lltrace = Py_GETENV("PYTHON_LLTRACE");
@@ -513,7 +517,6 @@ top: // Jump here after _PUSH_FRAME or likely branches
uint32_t oparg = instr->op.arg;
uint32_t extras = 0;
-
if (opcode == EXTENDED_ARG) {
instr++;
extras += 1;
@@ -543,11 +546,22 @@ top: // Jump here after _PUSH_FRAME or likely branches
int counter = instr[1].cache;
int bitcount = _Py_popcount32(counter);
int jump_likely = bitcount > 8;
+ if (jump_likely) {
+ confidence = confidence * bitcount / 16;
+ }
+ else {
+ confidence = confidence * (16 - bitcount) / 16;
+ }
+ if (confidence < CONFIDENCE_CUTOFF) {
+ DPRINTF(2, "Confidence too low (%d)\n", confidence);
+ OPT_STAT_INC(low_confidence);
+ goto done;
+ }
uint32_t uopcode = BRANCH_TO_GUARD[opcode - POP_JUMP_IF_FALSE][jump_likely];
_Py_CODEUNIT *next_instr = instr + 1 + _PyOpcode_Caches[_PyOpcode_Deopt[opcode]];
- DPRINTF(4, "%s(%d): counter=%x, bitcount=%d, likely=%d, uopcode=%s\n",
+ DPRINTF(2, "%s(%d): counter=%x, bitcount=%d, likely=%d, confidence=%d, uopcode=%s\n",
_PyUOpName(opcode), oparg,
- counter, bitcount, jump_likely, _PyUOpName(uopcode));
+ counter, bitcount, jump_likely, confidence, _PyUOpName(uopcode));
ADD_TO_TRACE(uopcode, max_length, 0, target);
if (jump_likely) {
_Py_CODEUNIT *target_instr = next_instr + oparg;
diff --git a/Python/specialize.c b/Python/specialize.c
index ba704cb..7c2a4a4 100644
--- a/Python/specialize.c
+++ b/Python/specialize.c
@@ -233,6 +233,7 @@ print_optimization_stats(FILE *out, OptimizationStats *stats)
fprintf(out, "Optimization trace too short: %" PRIu64 "\n", stats->trace_too_short);
fprintf(out, "Optimization inner loop: %" PRIu64 "\n", stats->inner_loop);
fprintf(out, "Optimization recursive call: %" PRIu64 "\n", stats->recursive_call);
+ fprintf(out, "Optimization low confidence: %" PRIu64 "\n", stats->low_confidence);
print_histogram(out, "Trace length", stats->trace_length_hist);
print_histogram(out, "Trace run length", stats->trace_run_length_hist);