linux-kernel - [PATCH bpf-next v11 10/11] libbpf: Optimize the performance of determine_ptr

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Message-Id: <20260108031645.1350069-11-dolinux.peng@gmail.com>
Date: Thu,  8 Jan 2026 11:16:44 +0800
From: Donglin Peng <dolinux.peng@...il.com>
To: ast@...nel.org,
	andrii.nakryiko@...il.com,
	eddyz87@...il.com
Cc: zhangxiaoqin@...omi.com,
	ihor.solodrai@...ux.dev,
	linux-kernel@...r.kernel.org,
	bpf@...r.kernel.org,
	Donglin Peng <pengdonglin@...omi.com>,
	Alan Maguire <alan.maguire@...cle.com>,
	Andrii Nakryiko <andrii@...nel.org>
Subject: [PATCH bpf-next v11 10/11] libbpf: Optimize the performance of determine_ptr_size

From: Donglin Peng <pengdonglin@...omi.com>

Leverage the performance improvement of btf__find_by_name_kind() when
BTF is sorted. For sorted BTF, the function uses binary search with
O(log n) complexity instead of linear search, providing significant
performance benefits, especially for large BTF like vmlinux.

Cc: Eduard Zingerman <eddyz87@...il.com>
Cc: Alexei Starovoitov <ast@...nel.org>
Cc: Andrii Nakryiko <andrii.nakryiko@...il.com>
Cc: Alan Maguire <alan.maguire@...cle.com>
Cc: Ihor Solodrai <ihor.solodrai@...ux.dev>
Cc: Xiaoqin Zhang <zhangxiaoqin@...omi.com>
Signed-off-by: Donglin Peng <pengdonglin@...omi.com>
Acked-by: Eduard Zingerman <eddyz87@...il.com>
Acked-by: Andrii Nakryiko <andrii@...nel.org>
---
 tools/lib/bpf/btf.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 277df0077df6..9e8911755a79 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -659,29 +659,21 @@ static int determine_ptr_size(const struct btf *btf)
 		"int long unsigned",
 	};
 	const struct btf_type *t;
-	const char *name;
-	int i, j, n;
+	int i, id;
 
 	if (btf->base_btf && btf->base_btf->ptr_sz > 0)
 		return btf->base_btf->ptr_sz;
 
-	n = btf__type_cnt(btf);
-	for (i = 1; i < n; i++) {
-		t = btf__type_by_id(btf, i);
-		if (!btf_is_int(t))
+	for (i = 0; i < ARRAY_SIZE(long_aliases); i++) {
+		id = btf__find_by_name_kind(btf, long_aliases[i], BTF_KIND_INT);
+		if (id < 0)
 			continue;
 
+		t = btf__type_by_id(btf, id);
 		if (t->size != 4 && t->size != 8)
 			continue;
 
-		name = btf__name_by_offset(btf, t->name_off);
-		if (!name)
-			continue;
-
-		for (j = 0; j < ARRAY_SIZE(long_aliases); j++) {
-			if (strcmp(name, long_aliases[j]) == 0)
-				return t->size;
-		}
+		return t->size;
 	}
 
 	return -1;
-- 
2.34.1