Here's a patch that adjusts several routines in nbtcompare.c and related
files to use the branchless integer comparison functions added in commit
6b80394. It's probably unlikely this produces a measurable benefit (at
least I've been unable to find any in my admittedly-limited testing), but
in theory it should save a cycle here and there. I was hoping that this
would trim many lines of code, but maintaining the STRESS_SORT_INT_MIN
stuff eats up most of what we save.
Anyway, I don't feel too strongly about this patch, but I went to the
trouble of writing it, and so I figured I'd post it.
--
nathan
>From bd2e1eb92b28cf855b529b09813f1b09084c7cfc Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Thu, 26 Sep 2024 15:03:32 -0500
Subject: [PATCH v1 1/1] micro-optimize nbtcompare.c routines
---
src/backend/access/nbtree/nbtcompare.c | 162 ++++++++++++-------------
src/backend/storage/page/itemptr.c | 18 +--
src/backend/utils/sort/tuplesort.c | 21 ++--
3 files changed, 96 insertions(+), 105 deletions(-)
diff --git a/src/backend/access/nbtree/nbtcompare.c
b/src/backend/access/nbtree/nbtcompare.c
index 1c72867c84..2df0c5dbe0 100644
--- a/src/backend/access/nbtree/nbtcompare.c
+++ b/src/backend/access/nbtree/nbtcompare.c
@@ -57,17 +57,16 @@
#include <limits.h>
+#include "common/int.h"
#include "utils/fmgrprotos.h"
#include "utils/sortsupport.h"
-#ifdef STRESS_SORT_INT_MIN
-#define A_LESS_THAN_B INT_MIN
-#define A_GREATER_THAN_B INT_MAX
-#else
-#define A_LESS_THAN_B (-1)
-#define A_GREATER_THAN_B 1
-#endif
-
+#define STRESS_SORT_INT_MIN_CMP(a, b) \
+( \
+ ((a) > (b)) ? INT_MAX : \
+ ((a) < (b)) ? INT_MIN : \
+ 0 \
+)
Datum
btboolcmp(PG_FUNCTION_ARGS)
@@ -84,7 +83,11 @@ btint2cmp(PG_FUNCTION_ARGS)
int16 a = PG_GETARG_INT16(0);
int16 b = PG_GETARG_INT16(1);
- PG_RETURN_INT32((int32) a - (int32) b);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s16(a, b));
+#endif
}
static int
@@ -93,7 +96,11 @@ btint2fastcmp(Datum x, Datum y, SortSupport ssup)
int16 a = DatumGetInt16(x);
int16 b = DatumGetInt16(y);
- return (int) a - (int) b;
+#ifdef STRESS_SORT_INT_MIN
+ return STRESS_SORT_INT_MIN_CMP(a, b);
+#else
+ return pg_cmp_s16(a, b);
+#endif
}
Datum
@@ -111,12 +118,11 @@ btint4cmp(PG_FUNCTION_ARGS)
int32 a = PG_GETARG_INT32(0);
int32 b = PG_GETARG_INT32(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s32(a, b));
+#endif
}
Datum
@@ -134,12 +140,11 @@ btint8cmp(PG_FUNCTION_ARGS)
int64 a = PG_GETARG_INT64(0);
int64 b = PG_GETARG_INT64(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s64(a, b));
+#endif
}
#if SIZEOF_DATUM < 8
@@ -149,12 +154,11 @@ btint8fastcmp(Datum x, Datum y, SortSupport ssup)
int64 a = DatumGetInt64(x);
int64 b = DatumGetInt64(y);
- if (a > b)
- return A_GREATER_THAN_B;
- else if (a == b)
- return 0;
- else
- return A_LESS_THAN_B;
+#ifdef STRESS_SORT_INT_MIN
+ return STRESS_SORT_INT_MIN_CMP(a, b);
+#else
+ return pg_cmp_s64(a, b);
+#endif
}
#endif
@@ -177,12 +181,11 @@ btint48cmp(PG_FUNCTION_ARGS)
int32 a = PG_GETARG_INT32(0);
int64 b = PG_GETARG_INT64(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s64(a, b));
+#endif
}
Datum
@@ -191,12 +194,11 @@ btint84cmp(PG_FUNCTION_ARGS)
int64 a = PG_GETARG_INT64(0);
int32 b = PG_GETARG_INT32(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s64(a, b));
+#endif
}
Datum
@@ -205,12 +207,11 @@ btint24cmp(PG_FUNCTION_ARGS)
int16 a = PG_GETARG_INT16(0);
int32 b = PG_GETARG_INT32(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s32(a, b));
+#endif
}
Datum
@@ -219,12 +220,11 @@ btint42cmp(PG_FUNCTION_ARGS)
int32 a = PG_GETARG_INT32(0);
int16 b = PG_GETARG_INT16(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s32(a, b));
+#endif
}
Datum
@@ -233,12 +233,11 @@ btint28cmp(PG_FUNCTION_ARGS)
int16 a = PG_GETARG_INT16(0);
int64 b = PG_GETARG_INT64(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s64(a, b));
+#endif
}
Datum
@@ -247,12 +246,11 @@ btint82cmp(PG_FUNCTION_ARGS)
int64 a = PG_GETARG_INT64(0);
int16 b = PG_GETARG_INT16(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_s64(a, b));
+#endif
}
Datum
@@ -261,12 +259,11 @@ btoidcmp(PG_FUNCTION_ARGS)
Oid a = PG_GETARG_OID(0);
Oid b = PG_GETARG_OID(1);
- if (a > b)
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else if (a == b)
- PG_RETURN_INT32(0);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(a, b));
+#else
+ PG_RETURN_INT32(pg_cmp_u32(a, b));
+#endif
}
static int
@@ -275,12 +272,11 @@ btoidfastcmp(Datum x, Datum y, SortSupport ssup)
Oid a = DatumGetObjectId(x);
Oid b = DatumGetObjectId(y);
- if (a > b)
- return A_GREATER_THAN_B;
- else if (a == b)
- return 0;
- else
- return A_LESS_THAN_B;
+#ifdef STRESS_SORT_INT_MIN
+ return STRESS_SORT_INT_MIN_CMP(a, b);
+#else
+ return pg_cmp_u32(a, b);
+#endif
}
Datum
@@ -305,12 +301,16 @@ btoidvectorcmp(PG_FUNCTION_ARGS)
for (i = 0; i < a->dim1; i++)
{
- if (a->values[i] != b->values[i])
+ Oid aval = a->values[i];
+ Oid bval = b->values[i];
+
+ if (aval != bval)
{
- if (a->values[i] > b->values[i])
- PG_RETURN_INT32(A_GREATER_THAN_B);
- else
- PG_RETURN_INT32(A_LESS_THAN_B);
+#ifdef STRESS_SORT_INT_MIN
+ PG_RETURN_INT32(STRESS_SORT_INT_MIN_CMP(aval, bval));
+#else
+ PG_RETURN_INT32(pg_cmp_u32(aval, bval));
+#endif
}
}
PG_RETURN_INT32(0);
diff --git a/src/backend/storage/page/itemptr.c
b/src/backend/storage/page/itemptr.c
index af21170307..d85592951e 100644
--- a/src/backend/storage/page/itemptr.c
+++ b/src/backend/storage/page/itemptr.c
@@ -14,6 +14,7 @@
*/
#include "postgres.h"
+#include "common/int.h"
#include "storage/itemptr.h"
@@ -57,18 +58,11 @@ ItemPointerCompare(ItemPointer arg1, ItemPointer arg2)
BlockNumber b1 = ItemPointerGetBlockNumberNoCheck(arg1);
BlockNumber b2 = ItemPointerGetBlockNumberNoCheck(arg2);
- if (b1 < b2)
- return -1;
- else if (b1 > b2)
- return 1;
- else if (ItemPointerGetOffsetNumberNoCheck(arg1) <
- ItemPointerGetOffsetNumberNoCheck(arg2))
- return -1;
- else if (ItemPointerGetOffsetNumberNoCheck(arg1) >
- ItemPointerGetOffsetNumberNoCheck(arg2))
- return 1;
- else
- return 0;
+ if (b1 != b2)
+ return pg_cmp_u32(b1, b2);
+
+ return pg_cmp_u16(ItemPointerGetOffsetNumberNoCheck(arg1),
+
ItemPointerGetOffsetNumberNoCheck(arg2));
}
/*
diff --git a/src/backend/utils/sort/tuplesort.c
b/src/backend/utils/sort/tuplesort.c
index c960cfa823..ec1ff3e656 100644
--- a/src/backend/utils/sort/tuplesort.c
+++ b/src/backend/utils/sort/tuplesort.c
@@ -102,6 +102,7 @@
#include <limits.h>
#include "commands/tablespace.h"
+#include "common/int.h"
#include "miscadmin.h"
#include "pg_trace.h"
#include "storage/shmem.h"
@@ -3138,12 +3139,18 @@ free_sort_tuple(Tuplesortstate *state, SortTuple *stup)
int
ssup_datum_unsigned_cmp(Datum x, Datum y, SortSupport ssup)
{
+#if SIZEOF_DATUM == 4
+ return pg_cmp_u32(x, y);
+#elif SIZEOF_DATUM == 8
+ return pg_cmp_u64(x, y);
+#else
if (x < y)
return -1;
else if (x > y)
return 1;
else
return 0;
+#endif
}
#if SIZEOF_DATUM >= 8
@@ -3153,12 +3160,7 @@ ssup_datum_signed_cmp(Datum x, Datum y, SortSupport ssup)
int64 xx = DatumGetInt64(x);
int64 yy = DatumGetInt64(y);
- if (xx < yy)
- return -1;
- else if (xx > yy)
- return 1;
- else
- return 0;
+ return pg_cmp_s64(xx, yy);
}
#endif
@@ -3168,10 +3170,5 @@ ssup_datum_int32_cmp(Datum x, Datum y, SortSupport ssup)
int32 xx = DatumGetInt32(x);
int32 yy = DatumGetInt32(y);
- if (xx < yy)
- return -1;
- else if (xx > yy)
- return 1;
- else
- return 0;
+ return pg_cmp_s32(xx, yy);
}
--
2.39.5 (Apple Git-154)
