Performance optimization of AVL tree comparator functions

perf: 2.75x faster ddt_entry_compare()
    First 256bits of ddt_key_t is a block checksum, which are expected
to be close to random data. Hence, on average, comparison only needs to
look at first few bytes of the keys. To reduce number of conditional
jump instructions, the result is computed as: sign(memcmp(k1, k2)).

Sign of an integer 'a' can be obtained as: `(0 < a) - (a < 0)` := {-1, 0, 1} ,
which is computed efficiently.  Synthetic performance evaluation of
original and new algorithm over 1G random keys on 2.6GHz Intel(R) Xeon(R)
CPU E5-2660 v3:

old	6.85789 s
new	2.49089 s

perf: 2.8x faster vdev_queue_offset_compare() and vdev_queue_timestamp_compare()
    Compute the result directly instead of using conditionals

perf: zfs_range_compare()
    Speedup between 1.1x - 2.5x, depending on compiler version and
optimization level.

perf: spa_error_entry_compare()
    `bcmp()` is not suitable for comparator use. Use `memcmp()` instead.

perf: 2.8x faster metaslab_compare() and metaslab_rangesize_compare()
perf: 2.8x faster zil_bp_compare()
perf: 2.8x faster mze_compare()
perf: faster dbuf_compare()
perf: faster compares in spa_misc
perf: 2.8x faster layout_hash_compare()
perf: 2.8x faster space_reftree_compare()
perf: libzfs: faster avl tree comparators
perf: guid_compare()
perf: dsl_deadlist_compare()
perf: perm_set_compare()
perf: 2x faster range_tree_seg_compare()
perf: faster unique_compare()
perf: faster vdev_cache _compare()
perf: faster vdev_uberblock_compare()
perf: faster fuid _compare()
perf: faster zfs_znode_hold_compare()

Signed-off-by: Gvozden Neskovic <[email protected]>
Signed-off-by: Richard Elling <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #5033

25 files changed, 148 insertions, 274 deletions

diff --git a/include/sys/avl.h b/include/sys/avl.h
index 10e0ddaee..ba51e2a79 100644
--- a/include/sys/avl.h
+++ b/include/sys/avl.h
@@ -105,6 +105,13 @@ extern "C" {
  * as is needed for any linked list implementation.
  */
 
+/*
+ * AVL comparator helpers
+ */
+#define	AVL_ISIGN(a)	(((a) > 0) - ((a) < 0))
+#define	AVL_CMP(a, b)	(((a) > (b)) - ((a) < (b)))
+#define	AVL_PCMP(a, b)	\
+	(((uintptr_t)(a) > (uintptr_t)(b)) - ((uintptr_t)(a) < (uintptr_t)(b)))
 
 /*
  * Type used for the root of the AVL tree.
diff --git a/include/sys/zfs_context.h b/include/sys/zfs_context.h
index 4a65600c1..bc5087551 100644
--- a/include/sys/zfs_context.h
+++ b/include/sys/zfs_context.h
@@ -131,6 +131,7 @@
  */
 
 #define	noinline	__attribute__((noinline))
+#define	likely(x)	__builtin_expect((x), 1)
 
 /*
  * Debugging
diff --git a/lib/libzfs/libzfs_dataset.c b/lib/libzfs/libzfs_dataset.c
index bd90bf0bf..3ac31ad1d 100755
--- a/lib/libzfs/libzfs_dataset.c
+++ b/lib/libzfs/libzfs_dataset.c
@@ -674,15 +674,13 @@ typedef struct mnttab_node {
 static int
 libzfs_mnttab_cache_compare(const void *arg1, const void *arg2)
 {
-	const mnttab_node_t *mtn1 = arg1;
-	const mnttab_node_t *mtn2 = arg2;
+	const mnttab_node_t *mtn1 = (const mnttab_node_t *)arg1;
+	const mnttab_node_t *mtn2 = (const mnttab_node_t *)arg2;
 	int rv;
 
 	rv = strcmp(mtn1->mtn_mt.mnt_special, mtn2->mtn_mt.mnt_special);
 
-	if (rv == 0)
-		return (0);
-	return (rv > 0 ? 1 : -1);
+	return (AVL_ISIGN(rv));
 }
 
 void
diff --git a/lib/libzfs/libzfs_iter.c b/lib/libzfs/libzfs_iter.c
index 96f657465..c656db6fc 100644
--- a/lib/libzfs/libzfs_iter.c
+++ b/lib/libzfs/libzfs_iter.c
@@ -272,12 +272,7 @@ zfs_snapshot_compare(const void *larg, const void *rarg)
 	lcreate = zfs_prop_get_int(l, ZFS_PROP_CREATETXG);
 	rcreate = zfs_prop_get_int(r, ZFS_PROP_CREATETXG);
 
-	if (lcreate < rcreate)
-		return (-1);
-	else if (lcreate > rcreate)
-		return (+1);
-	else
-		return (0);
+	return (AVL_CMP(lcreate, rcreate));
 }
 
 int
diff --git a/lib/libzfs/libzfs_sendrecv.c b/lib/libzfs/libzfs_sendrecv.c
index 0d19c3bf4..c21ce19af 100644
--- a/lib/libzfs/libzfs_sendrecv.c
+++ b/lib/libzfs/libzfs_sendrecv.c
@@ -475,15 +475,10 @@ typedef struct fsavl_node {
 static int
 fsavl_compare(const void *arg1, const void *arg2)
 {
-	const fsavl_node_t *fn1 = arg1;
-	const fsavl_node_t *fn2 = arg2;
+	const fsavl_node_t *fn1 = (const fsavl_node_t *)arg1;
+	const fsavl_node_t *fn2 = (const fsavl_node_t *)arg2;
 
-	if (fn1->fn_guid > fn2->fn_guid)
-		return (+1);
-	else if (fn1->fn_guid < fn2->fn_guid)
-		return (-1);
-	else
-		return (0);
+	return (AVL_CMP(fn1->fn_guid, fn2->fn_guid));
 }
 
 /*
diff --git a/module/zfs/ddt.c b/module/zfs/ddt.c
index 12c1b7300..7d2383968 100644
--- a/module/zfs/ddt.c
+++ b/module/zfs/ddt.c
@@ -811,23 +811,32 @@ ddt_prefetch(spa_t *spa, const blkptr_t *bp)
 	}
 }
 
+/*
+ * Opaque struct used for ddt_key comparison
+ */
+#define	DDT_KEY_CMP_LEN	(sizeof (ddt_key_t) / sizeof (uint16_t))
+
+typedef struct ddt_key_cmp {
+	uint16_t	u16[DDT_KEY_CMP_LEN];
+} ddt_key_cmp_t;
+
 int
 ddt_entry_compare(const void *x1, const void *x2)
 {
 	const ddt_entry_t *dde1 = x1;
 	const ddt_entry_t *dde2 = x2;
-	const uint64_t *u1 = (const uint64_t *)&dde1->dde_key;
-	const uint64_t *u2 = (const uint64_t *)&dde2->dde_key;
+	const ddt_key_cmp_t *k1 = (const ddt_key_cmp_t *)&dde1->dde_key;
+	const ddt_key_cmp_t *k2 = (const ddt_key_cmp_t *)&dde2->dde_key;
+	int32_t cmp = 0;
 	int i;
 
-	for (i = 0; i < DDT_KEY_WORDS; i++) {
-		if (u1[i] < u2[i])
-			return (-1);
-		if (u1[i] > u2[i])
-			return (1);
+	for (i = 0; i < DDT_KEY_CMP_LEN; i++) {
+		cmp = (int32_t)k1->u16[i] - (int32_t)k2->u16[i];
+		if (likely(cmp))
+			break;
 	}
 
-	return (0);
+	return (AVL_ISIGN(cmp));
 }
 
 static ddt_t *
diff --git a/module/zfs/dmu_send.c b/module/zfs/dmu_send.c
index 56936cf23..21007a9d1 100644
--- a/module/zfs/dmu_send.c
+++ b/module/zfs/dmu_send.c
@@ -1793,14 +1793,10 @@ typedef struct guid_map_entry {
 static int
 guid_compare(const void *arg1, const void *arg2)
 {
-	const guid_map_entry_t *gmep1 = arg1;
-	const guid_map_entry_t *gmep2 = arg2;
+	const guid_map_entry_t *gmep1 = (const guid_map_entry_t *)arg1;
+	const guid_map_entry_t *gmep2 = (const guid_map_entry_t *)arg2;
 
-	if (gmep1->guid < gmep2->guid)
-		return (-1);
-	else if (gmep1->guid > gmep2->guid)
-		return (1);
-	return (0);
+	return (AVL_CMP(gmep1->guid, gmep2->guid));
 }
 
 static void
diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c
index 8015f54ed..abc004bd4 100644
--- a/module/zfs/dnode.c
+++ b/module/zfs/dnode.c
@@ -69,19 +69,13 @@ dbuf_compare(const void *x1, const void *x2)
 	const dmu_buf_impl_t *d1 = x1;
 	const dmu_buf_impl_t *d2 = x2;
 
-	if (d1->db_level < d2->db_level) {
-		return (-1);
-	}
-	if (d1->db_level > d2->db_level) {
-		return (1);
-	}
+	int cmp = AVL_CMP(d1->db_level, d2->db_level);
+	if (likely(cmp))
+		return (cmp);
 
-	if (d1->db_blkid < d2->db_blkid) {
-		return (-1);
-	}
-	if (d1->db_blkid > d2->db_blkid) {
-		return (1);
-	}
+	cmp = AVL_CMP(d1->db_blkid, d2->db_blkid);
+	if (likely(cmp))
+		return (cmp);
 
 	if (d1->db_state == DB_SEARCH) {
 		ASSERT3S(d2->db_state, !=, DB_SEARCH);
@@ -91,13 +85,7 @@ dbuf_compare(const void *x1, const void *x2)
 		return (1);
 	}
 
-	if ((uintptr_t)d1 < (uintptr_t)d2) {
-		return (-1);
-	}
-	if ((uintptr_t)d1 > (uintptr_t)d2) {
-		return (1);
-	}
-	return (0);
+	return (AVL_PCMP(d1, d2));
 }
 
 /* ARGSUSED */
diff --git a/module/zfs/dsl_deadlist.c b/module/zfs/dsl_deadlist.c
index fa83a10a5..0b99e9713 100644
--- a/module/zfs/dsl_deadlist.c
+++ b/module/zfs/dsl_deadlist.c
@@ -54,15 +54,10 @@
 static int
 dsl_deadlist_compare(const void *arg1, const void *arg2)
 {
-	const dsl_deadlist_entry_t *dle1 = arg1;
-	const dsl_deadlist_entry_t *dle2 = arg2;
+	const dsl_deadlist_entry_t *dle1 = (const dsl_deadlist_entry_t *)arg1;
+	const dsl_deadlist_entry_t *dle2 = (const dsl_deadlist_entry_t *)arg2;
 
-	if (dle1->dle_mintxg < dle2->dle_mintxg)
-		return (-1);
-	else if (dle1->dle_mintxg > dle2->dle_mintxg)
-		return (+1);
-	else
-		return (0);
+	return (AVL_CMP(dle1->dle_mintxg, dle2->dle_mintxg));
 }
 
 static void
diff --git a/module/zfs/dsl_deleg.c b/module/zfs/dsl_deleg.c
index eb39cff57..f17cedb08 100644
--- a/module/zfs/dsl_deleg.c
+++ b/module/zfs/dsl_deleg.c
@@ -393,14 +393,13 @@ typedef struct perm_set {
 static int
 perm_set_compare(const void *arg1, const void *arg2)
 {
-	const perm_set_t *node1 = arg1;
-	const perm_set_t *node2 = arg2;
+	const perm_set_t *node1 = (const perm_set_t *)arg1;
+	const perm_set_t *node2 = (const perm_set_t *)arg2;
 	int val;
 
 	val = strcmp(node1->p_setname, node2->p_setname);
-	if (val == 0)
-		return (0);
-	return (val > 0 ? 1 : -1);
+
+	return (AVL_ISIGN(val));
 }
 
 /*
diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c
index a4cf39a3f..9de65c86e 100644
--- a/module/zfs/metaslab.c
+++ b/module/zfs/metaslab.c
@@ -399,25 +399,16 @@ metaslab_class_expandable_space(metaslab_class_t *mc)
 static int
 metaslab_compare(const void *x1, const void *x2)
 {
-	const metaslab_t *m1 = x1;
-	const metaslab_t *m2 = x2;
+	const metaslab_t *m1 = (const metaslab_t *)x1;
+	const metaslab_t *m2 = (const metaslab_t *)x2;
 
-	if (m1->ms_weight < m2->ms_weight)
-		return (1);
-	if (m1->ms_weight > m2->ms_weight)
-		return (-1);
+	int cmp = AVL_CMP(m2->ms_weight, m1->ms_weight);
+	if (likely(cmp))
+		return (cmp);
 
-	/*
-	 * If the weights are identical, use the offset to force uniqueness.
-	 */
-	if (m1->ms_start < m2->ms_start)
-		return (-1);
-	if (m1->ms_start > m2->ms_start)
-		return (1);
+	IMPLY(AVL_CMP(m1->ms_start, m2->ms_start) == 0, m1 == m2);
 
-	ASSERT3P(m1, ==, m2);
-
-	return (0);
+	return (AVL_CMP(m1->ms_start, m2->ms_start));
 }
 
 /*
@@ -795,18 +786,11 @@ metaslab_rangesize_compare(const void *x1, const void *x2)
 	uint64_t rs_size1 = r1->rs_end - r1->rs_start;
 	uint64_t rs_size2 = r2->rs_end - r2->rs_start;
 
-	if (rs_size1 < rs_size2)
-		return (-1);
-	if (rs_size1 > rs_size2)
-		return (1);
+	int cmp = AVL_CMP(rs_size1, rs_size2);
+	if (likely(cmp))
+		return (cmp);
 
-	if (r1->rs_start < r2->rs_start)
-		return (-1);
-
-	if (r1->rs_start > r2->rs_start)
-		return (1);
-
-	return (0);
+	return (AVL_CMP(r1->rs_start, r2->rs_start));
 }
 
 /*
diff --git a/module/zfs/range_tree.c b/module/zfs/range_tree.c
index 6422fd1c1..ebef7f447 100644
--- a/module/zfs/range_tree.c
+++ b/module/zfs/range_tree.c
@@ -111,20 +111,13 @@ range_tree_stat_decr(range_tree_t *rt, range_seg_t *rs)
 static int
 range_tree_seg_compare(const void *x1, const void *x2)
 {
-	const range_seg_t *r1 = x1;
-	const range_seg_t *r2 = x2;
+	const range_seg_t *r1 = (const range_seg_t *)x1;
+	const range_seg_t *r2 = (const range_seg_t *)x2;
 
-	if (r1->rs_start < r2->rs_start) {
-		if (r1->rs_end > r2->rs_start)
-			return (0);
-		return (-1);
-	}
-	if (r1->rs_start > r2->rs_start) {
-		if (r1->rs_start < r2->rs_end)
-			return (0);
-		return (1);
-	}
-	return (0);
+	ASSERT3U(r1->rs_start, <=, r1->rs_end);
+	ASSERT3U(r2->rs_start, <=, r2->rs_end);
+
+	return ((r1->rs_start >= r2->rs_end) - (r1->rs_end <= r2->rs_start));
 }
 
 range_tree_t *
diff --git a/module/zfs/sa.c b/module/zfs/sa.c
index adc301512..1548c5634 100644
--- a/module/zfs/sa.c
+++ b/module/zfs/sa.c
@@ -241,31 +241,23 @@ sa_cache_fini(void)
 static int
 layout_num_compare(const void *arg1, const void *arg2)
 {
-	const sa_lot_t *node1 = arg1;
-	const sa_lot_t *node2 = arg2;
+	const sa_lot_t *node1 = (const sa_lot_t *)arg1;
+	const sa_lot_t *node2 = (const sa_lot_t *)arg2;
 
-	if (node1->lot_num > node2->lot_num)
-		return (1);
-	else if (node1->lot_num < node2->lot_num)
-		return (-1);
-	return (0);
+	return (AVL_CMP(node1->lot_num, node2->lot_num));
 }
 
 static int
 layout_hash_compare(const void *arg1, const void *arg2)
 {
-	const sa_lot_t *node1 = arg1;
-	const sa_lot_t *node2 = arg2;
+	const sa_lot_t *node1 = (const sa_lot_t *)arg1;
+	const sa_lot_t *node2 = (const sa_lot_t *)arg2;
 
-	if (node1->lot_hash > node2->lot_hash)
-		return (1);
-	if (node1->lot_hash < node2->lot_hash)
-		return (-1);
-	if (node1->lot_instance > node2->lot_instance)
-		return (1);
-	if (node1->lot_instance < node2->lot_instance)
-		return (-1);
-	return (0);
+	int cmp = AVL_CMP(node1->lot_hash, node2->lot_hash);
+	if (likely(cmp))
+		return (cmp);
+
+	return (AVL_CMP(node1->lot_instance, node2->lot_instance));
 }
 
 boolean_t
diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index 374322a03..463b84d3d 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -822,19 +822,14 @@ spa_change_guid(spa_t *spa)
 static int
 spa_error_entry_compare(const void *a, const void *b)
 {
-	spa_error_entry_t *sa = (spa_error_entry_t *)a;
-	spa_error_entry_t *sb = (spa_error_entry_t *)b;
+	const spa_error_entry_t *sa = (const spa_error_entry_t *)a;
+	const spa_error_entry_t *sb = (const spa_error_entry_t *)b;
 	int ret;
 
-	ret = bcmp(&sa->se_bookmark, &sb->se_bookmark,
+	ret = memcmp(&sa->se_bookmark, &sb->se_bookmark,
 	    sizeof (zbookmark_phys_t));
 
-	if (ret < 0)
-		return (-1);
-	else if (ret > 0)
-		return (1);
-	else
-		return (0);
+	return (AVL_ISIGN(ret));
 }
 
 /*
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index d1303b5c2..6330a6a6b 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -797,18 +797,13 @@ typedef struct spa_aux {
 	int		aux_count;
 } spa_aux_t;
 
-static int
+static inline int
 spa_aux_compare(const void *a, const void *b)
 {
-	const spa_aux_t *sa = a;
-	const spa_aux_t *sb = b;
+	const spa_aux_t *sa = (const spa_aux_t *)a;
+	const spa_aux_t *sb = (const spa_aux_t *)b;
 
-	if (sa->aux_guid < sb->aux_guid)
-		return (-1);
-	else if (sa->aux_guid > sb->aux_guid)
-		return (1);
-	else
-		return (0);
+	return (AVL_CMP(sa->aux_guid, sb->aux_guid));
 }
 
 void
@@ -1774,11 +1769,8 @@ spa_name_compare(const void *a1, const void *a2)
 	int s;
 
 	s = strcmp(s1->spa_name, s2->spa_name);
-	if (s > 0)
-		return (1);
-	if (s < 0)
-		return (-1);
-	return (0);
+
+	return (AVL_ISIGN(s));
 }
 
 void
diff --git a/module/zfs/space_reftree.c b/module/zfs/space_reftree.c
index a508092c5..efbf95099 100644
--- a/module/zfs/space_reftree.c
+++ b/module/zfs/space_reftree.c
@@ -54,20 +54,14 @@
 static int
 space_reftree_compare(const void *x1, const void *x2)
 {
-	const space_ref_t *sr1 = x1;
-	const space_ref_t *sr2 = x2;
+	const space_ref_t *sr1 = (const space_ref_t *)x1;
+	const space_ref_t *sr2 = (const space_ref_t *)x2;
 
-	if (sr1->sr_offset < sr2->sr_offset)
-		return (-1);
-	if (sr1->sr_offset > sr2->sr_offset)
-		return (1);
+	int cmp = AVL_CMP(sr1->sr_offset, sr2->sr_offset);
+	if (likely(cmp))
+		return (cmp);
 
-	if (sr1 < sr2)
-		return (-1);
-	if (sr1 > sr2)
-		return (1);
-
-	return (0);
+	return (AVL_PCMP(sr1, sr2));
 }
 
 void
diff --git a/module/zfs/unique.c b/module/zfs/unique.c
index 8c1d2e2f9..5cdd025f4 100644
--- a/module/zfs/unique.c
+++ b/module/zfs/unique.c
@@ -42,14 +42,10 @@ typedef struct unique {
 static int
 unique_compare(const void *a, const void *b)
 {
-	const unique_t *una = a;
-	const unique_t *unb = b;
-
-	if (una->un_value < unb->un_value)
-		return (-1);
-	if (una->un_value > unb->un_value)
-		return (+1);
-	return (0);
+	const unique_t *una = (const unique_t *)a;
+	const unique_t *unb = (const unique_t *)b;
+
+	return (AVL_CMP(una->un_value, unb->un_value));
 }
 
 void
diff --git a/module/zfs/vdev_cache.c b/module/zfs/vdev_cache.c
index e802240c1..d7de7c5c9 100644
--- a/module/zfs/vdev_cache.c
+++ b/module/zfs/vdev_cache.c
@@ -104,29 +104,24 @@ static vdc_stats_t vdc_stats = {
 
 #define	VDCSTAT_BUMP(stat)	atomic_inc_64(&vdc_stats.stat.value.ui64);
 
-static int
+static inline int
 vdev_cache_offset_compare(const void *a1, const void *a2)
 {
-	const vdev_cache_entry_t *ve1 = a1;
-	const vdev_cache_entry_t *ve2 = a2;
-
-	if (ve1->ve_offset < ve2->ve_offset)
-		return (-1);
-	if (ve1->ve_offset > ve2->ve_offset)
-		return (1);
-	return (0);
+	const vdev_cache_entry_t *ve1 = (const vdev_cache_entry_t *)a1;
+	const vdev_cache_entry_t *ve2 = (const vdev_cache_entry_t *)a2;
+
+	return (AVL_CMP(ve1->ve_offset, ve2->ve_offset));
 }
 
 static int
 vdev_cache_lastused_compare(const void *a1, const void *a2)
 {
-	const vdev_cache_entry_t *ve1 = a1;
-	const vdev_cache_entry_t *ve2 = a2;
+	const vdev_cache_entry_t *ve1 = (const vdev_cache_entry_t *)a1;
+	const vdev_cache_entry_t *ve2 = (const vdev_cache_entry_t *)a2;
 
-	if (ddi_time_before(ve1->ve_lastused, ve2->ve_lastused))
-		return (-1);
-	if (ddi_time_after(ve1->ve_lastused, ve2->ve_lastused))
-		return (1);
+	int cmp = AVL_CMP(ve1->ve_lastused, ve2->ve_lastused);
+	if (likely(cmp))
+		return (cmp);
 
 	/*
 	 * Among equally old entries, sort by offset to ensure uniqueness.
diff --git a/module/zfs/vdev_label.c b/module/zfs/vdev_label.c
index 1925c67ed..95bf4392f 100644
--- a/module/zfs/vdev_label.c
+++ b/module/zfs/vdev_label.c
@@ -1015,19 +1015,13 @@ retry:
  * among uberblocks with equal txg, choose the one with the latest timestamp.
  */
 static int
-vdev_uberblock_compare(uberblock_t *ub1, uberblock_t *ub2)
+vdev_uberblock_compare(const uberblock_t *ub1, const uberblock_t *ub2)
 {
-	if (ub1->ub_txg < ub2->ub_txg)
-		return (-1);
-	if (ub1->ub_txg > ub2->ub_txg)
-		return (1);
+	int cmp = AVL_CMP(ub1->ub_txg, ub2->ub_txg);
+	if (likely(cmp))
+		return (cmp);
 
-	if (ub1->ub_timestamp < ub2->ub_timestamp)
-		return (-1);
-	if (ub1->ub_timestamp > ub2->ub_timestamp)
-		return (1);
-
-	return (0);
+	return (AVL_CMP(ub1->ub_timestamp, ub2->ub_timestamp));
 }
 
 struct ubl_cbdata {
diff --git a/module/zfs/vdev_queue.c b/module/zfs/vdev_queue.c
index 8522c2627..4cffa500b 100644
--- a/module/zfs/vdev_queue.c
+++ b/module/zfs/vdev_queue.c
@@ -174,20 +174,15 @@ int zfs_vdev_write_gap_limit = 4 << 10;
 int
 vdev_queue_offset_compare(const void *x1, const void *x2)
 {
-	const zio_t *z1 = x1;
-	const zio_t *z2 = x2;
+	const zio_t *z1 = (const zio_t *)x1;
+	const zio_t *z2 = (const zio_t *)x2;
 
-	if (z1->io_offset < z2->io_offset)
-		return (-1);
-	if (z1->io_offset > z2->io_offset)
-		return (1);
+	int cmp = AVL_CMP(z1->io_offset, z2->io_offset);
 
-	if (z1 < z2)
-		return (-1);
-	if (z1 > z2)
-		return (1);
+	if (likely(cmp))
+		return (cmp);
 
-	return (0);
+	return (AVL_PCMP(z1, z2));
 }
 
 static inline avl_tree_t *
@@ -209,20 +204,15 @@ vdev_queue_type_tree(vdev_queue_t *vq, zio_type_t t)
 int
 vdev_queue_timestamp_compare(const void *x1, const void *x2)
 {
-	const zio_t *z1 = x1;
-	const zio_t *z2 = x2;
+	const zio_t *z1 = (const zio_t *)x1;
+	const zio_t *z2 = (const zio_t *)x2;
 
-	if (z1->io_timestamp < z2->io_timestamp)
-		return (-1);
-	if (z1->io_timestamp > z2->io_timestamp)
-		return (1);
+	int cmp = AVL_CMP(z1->io_timestamp, z2->io_timestamp);
 
-	if (z1 < z2)
-		return (-1);
-	if (z1 > z2)
-		return (1);
+	if (likely(cmp))
+		return (cmp);
 
-	return (0);
+	return (AVL_PCMP(z1, z2));
 }
 
 static int
diff --git a/module/zfs/zap_micro.c b/module/zfs/zap_micro.c
index bc0a5e71d..df952146b 100644
--- a/module/zfs/zap_micro.c
+++ b/module/zfs/zap_micro.c
@@ -257,15 +257,11 @@ mze_compare(const void *arg1, const void *arg2)
 	const mzap_ent_t *mze1 = arg1;
 	const mzap_ent_t *mze2 = arg2;
 
-	if (mze1->mze_hash > mze2->mze_hash)
-		return (+1);
-	if (mze1->mze_hash < mze2->mze_hash)
-		return (-1);
-	if (mze1->mze_cd > mze2->mze_cd)
-		return (+1);
-	if (mze1->mze_cd < mze2->mze_cd)
-		return (-1);
-	return (0);
+	int cmp = AVL_CMP(mze1->mze_hash, mze2->mze_hash);
+	if (likely(cmp))
+		return (cmp);
+
+	return (AVL_CMP(mze1->mze_cd, mze2->mze_cd));
 }
 
 static void
diff --git a/module/zfs/zfs_fuid.c b/module/zfs/zfs_fuid.c
index eb0ffe419..93b7a8b84 100644
--- a/module/zfs/zfs_fuid.c
+++ b/module/zfs/zfs_fuid.c
@@ -71,14 +71,10 @@ static char *nulldomain = "";
 static int
 idx_compare(const void *arg1, const void *arg2)
 {
-	const fuid_domain_t *node1 = arg1;
-	const fuid_domain_t *node2 = arg2;
+	const fuid_domain_t *node1 = (const fuid_domain_t *)arg1;
+	const fuid_domain_t *node2 = (const fuid_domain_t *)arg2;
 
-	if (node1->f_idx < node2->f_idx)
-		return (-1);
-	else if (node1->f_idx > node2->f_idx)
-		return (1);
-	return (0);
+	return (AVL_CMP(node1->f_idx, node2->f_idx));
 }
 
 /*
@@ -87,14 +83,13 @@ idx_compare(const void *arg1, const void *arg2)
 static int
 domain_compare(const void *arg1, const void *arg2)
 {
-	const fuid_domain_t *node1 = arg1;
-	const fuid_domain_t *node2 = arg2;
+	const fuid_domain_t *node1 = (const fuid_domain_t *)arg1;
+	const fuid_domain_t *node2 = (const fuid_domain_t *)arg2;
 	int val;
 
 	val = strcmp(node1->f_ksid->kd_name, node2->f_ksid->kd_name);
-	if (val == 0)
-		return (0);
-	return (val > 0 ? 1 : -1);
+
+	return (AVL_ISIGN(val));
 }
 
 void
diff --git a/module/zfs/zfs_rlock.c b/module/zfs/zfs_rlock.c
index fd3e8a68d..d3f68537f 100644
--- a/module/zfs/zfs_rlock.c
+++ b/module/zfs/zfs_rlock.c
@@ -617,14 +617,10 @@ zfs_range_reduce(rl_t *rl, uint64_t off, uint64_t len)
 int
 zfs_range_compare(const void *arg1, const void *arg2)
 {
-	const rl_t *rl1 = arg1;
-	const rl_t *rl2 = arg2;
-
-	if (rl1->r_off > rl2->r_off)
-		return (1);
-	if (rl1->r_off < rl2->r_off)
-		return (-1);
-	return (0);
+	const rl_t *rl1 = (const rl_t *)arg1;
+	const rl_t *rl2 = (const rl_t *)arg2;
+
+	return (AVL_CMP(rl1->r_off, rl2->r_off));
 }
 
 #ifdef _KERNEL
diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index 74502935c..b6abf46eb 100644
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -228,15 +228,10 @@ zfs_znode_fini(void)
 int
 zfs_znode_hold_compare(const void *a, const void *b)
 {
-	const znode_hold_t *zh_a = a;
-	const znode_hold_t *zh_b = b;
+	const znode_hold_t *zh_a = (const znode_hold_t *)a;
+	const znode_hold_t *zh_b = (const znode_hold_t *)b;
 
-	if (zh_a->zh_obj < zh_b->zh_obj)
-		return (-1);
-	else if (zh_a->zh_obj > zh_b->zh_obj)
-		return (1);
-	else
-		return (0);
+	return (AVL_CMP(zh_a->zh_obj, zh_b->zh_obj));
 }
 
 boolean_t
diff --git a/module/zfs/zil.c b/module/zfs/zil.c
index 863ccb930..c538251c3 100644
--- a/module/zfs/zil.c
+++ b/module/zfs/zil.c
@@ -123,17 +123,11 @@ zil_bp_compare(const void *x1, const void *x2)
 	const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva;
 	const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva;
 
-	if (DVA_GET_VDEV(dva1) < DVA_GET_VDEV(dva2))
-		return (-1);
-	if (DVA_GET_VDEV(dva1) > DVA_GET_VDEV(dva2))
-		return (1);
+	int cmp = AVL_CMP(DVA_GET_VDEV(dva1), DVA_GET_VDEV(dva2));
+	if (likely(cmp))
+		return (cmp);
 
-	if (DVA_GET_OFFSET(dva1) < DVA_GET_OFFSET(dva2))
-		return (-1);
-	if (DVA_GET_OFFSET(dva1) > DVA_GET_OFFSET(dva2))
-		return (1);
-
-	return (0);
+	return (AVL_CMP(DVA_GET_OFFSET(dva1), DVA_GET_OFFSET(dva2)));
 }
 
 static void
@@ -786,12 +780,7 @@ zil_vdev_compare(const void *x1, const void *x2)
 	const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev;
 	const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev;
 
-	if (v1 < v2)
-		return (-1);
-	if (v1 > v2)
-		return (1);
-
-	return (0);
+	return (AVL_CMP(v1, v2));
 }
 
 void
@@ -1257,12 +1246,7 @@ zil_aitx_compare(const void *x1, const void *x2)
 	const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid;
 	const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid;
 
-	if (o1 < o2)
-		return (-1);
-	if (o1 > o2)
-		return (1);
-
-	return (0);
+	return (AVL_CMP(o1, o2));
 }
 
 /*