Try adjusting the confidence less conservatively on 100% predicted br…

…anches
brandtbucher · Sep 5, 2024 · d467f6c · d467f6c
1 parent 8b9b14d
commit d467f6c
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/Python/optimizer.c b/Python/optimizer.c
@@ -664,14 +664,14 @@ translate_bytecode_to_trace(
                 int bitcount = _Py_popcount32(counter);
                 int jump_likely = bitcount > 8;
                 /* If bitcount is 8 (half the jumps were taken), adjust confidence by 50%.
-                   If it's 16 or 0 (all or none were taken), adjust by 10%
+                   If it's 16 or 0 (all or none were taken), adjust by ~6%
                    (since the future is still somewhat uncertain).
                    For values in between, adjust proportionally. */
                 if (jump_likely) {
-                    confidence = confidence * (bitcount + 2) / 20;
+                    confidence = confidence * (bitcount + 1) / 18;
                 }
                 else {
-                    confidence = confidence * (18 - bitcount) / 20;
+                    confidence = confidence * (17 - bitcount) / 18;
                 }
                 uint32_t uopcode = BRANCH_TO_GUARD[opcode - POP_JUMP_IF_FALSE][jump_likely];
                 DPRINTF(2, "%d: %s(%d): counter=%04x, bitcount=%d, likely=%d, confidence=%d, uopcode=%s\n",