linux-kernel - Re: [PATCH bpf-next v9 10/10] libbpf: Optimize the performance of determine_ptr

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Message-ID: <CAErzpmvNF3HZHfMYzmwVL77q0_V9qT58iQqRy=UnX905N54_XA@mail.gmail.com>
Date: Wed, 17 Dec 2025 16:38:05 +0800
From: Donglin Peng <dolinux.peng@...il.com>
To: Eduard Zingerman <eddyz87@...il.com>
Cc: ast@...nel.org, andrii.nakryiko@...il.com, zhangxiaoqin@...omi.com, 
	ihor.solodrai@...ux.dev, linux-kernel@...r.kernel.org, bpf@...r.kernel.org, 
	pengdonglin <pengdonglin@...omi.com>, Alan Maguire <alan.maguire@...cle.com>
Subject: Re: [PATCH bpf-next v9 10/10] libbpf: Optimize the performance of determine_ptr_size

On Wed, Dec 17, 2025 at 3:06 PM Eduard Zingerman <eddyz87@...il.com> wrote:
>
> On Mon, 2025-12-08 at 14:23 +0800, Donglin Peng wrote:
> > From: pengdonglin <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.
>
> Is this a big win?

Here is a comparison:

  w/:     1us
w/o: 351us

> I don't like having two code paths for something which is done once
> per BTF load. If it is a big win, maybe just stick with the first loop
> (the one that uses btf__find_by_name_kind())? Wdyt?

Yes, I agree and will only keep the first loop in the next version.

>
> [...]