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Move TupleTableSlots boolean member into one flag variable.

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There's several reasons for this change:
1) It reduces the total size of TupleTableSlot / reduces alignment
   padding, making the commonly accessed members fit into a single
   cacheline (but we currently do not force proper alignment, so
   that's not yet guaranteed to be helpful)
2) Combining the booleans into a flag allows to combine read/writes
   from memory.
3) With the upcoming slot abstraction changes, it allows to have core
   and extended flags, in a memory efficient way.

Author: Ashutosh Bapat and Andres Freund
Discussion: https://postgr.es/m/20180220224318.gw4oe5jadhpmcdnm@alap3.anarazel.de
This commit is contained in:
Andres Freund
2018-10-15 15:24:33 -07:00
parent 9d906f1119
commit c5257345ef
8 changed files with 116 additions and 72 deletions
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9
src/backend/jit/llvm/llvmjit_deform.c
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@ -60,7 +60,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc, int natts)
LLVMValueRef v_tts_values;
LLVMValueRef v_tts_nulls;
LLVMValueRef v_slotoffp;
LLVMValueRef v_slowp;
LLVMValueRef v_flagsp;
LLVMValueRef v_nvalidp;
LLVMValueRef v_nvalid;
LLVMValueRef v_maxatt;
@ -168,7 +168,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc, int natts)
"tts_ISNULL");
v_slotoffp = LLVMBuildStructGEP(b, v_slot, FIELDNO_TUPLETABLESLOT_OFF, "");
v_slowp = LLVMBuildStructGEP(b, v_slot, FIELDNO_TUPLETABLESLOT_SLOW, "");
v_flagsp = LLVMBuildStructGEP(b, v_slot, FIELDNO_TUPLETABLESLOT_FLAGS, "");
v_nvalidp = LLVMBuildStructGEP(b, v_slot, FIELDNO_TUPLETABLESLOT_NVALID, "");
v_tupleheaderp =
@ -690,11 +690,14 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc, int natts)
{
LLVMValueRef v_off = LLVMBuildLoad(b, v_offp, "");
LLVMValueRef v_flags;
LLVMBuildStore(b, l_int16_const(natts), v_nvalidp);
v_off = LLVMBuildTrunc(b, v_off, LLVMInt32Type(), "");
LLVMBuildStore(b, v_off, v_slotoffp);
LLVMBuildStore(b, l_int8_const(1), v_slowp);
v_flags = LLVMBuildLoad(b, v_flagsp, "tts_flags");
v_flags = LLVMBuildOr(b, v_flags, l_int16_const(TTS_FLAG_SLOW), "");
LLVMBuildStore(b, v_flags, v_flagsp);
LLVMBuildRetVoid(b);
}