linux-kernel - Re: [PATCH] scripts/dtc/flattree.c: stringtable

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Message-ID: <CAL_JsqKQEiGvt8H+7vO38PkMsmb3+CHvb=d2QcLd6zBOfNLs=A@mail.gmail.com>
Date: Fri, 22 Aug 2025 08:34:45 -0500
From: Rob Herring <robh@...nel.org>
To: Alex Tran <alex.t.tran@...il.com>
Cc: saravanak@...gle.com, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] scripts/dtc/flattree.c: stringtable_insert optimization

On Fri, Aug 22, 2025 at 1:04 AM Alex Tran <alex.t.tran@...il.com> wrote:
>
> Increment string by string instead of character by character.

Why? Are you doing something where this provides measurable improvement?

>
> Signed-off-by: Alex Tran <alex.t.tran@...il.com>
> ---
>  scripts/dtc/flattree.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)

This is a copy of upstream dtc. If you want to make changes to dtc,
you have to submit them upstream.

>
> diff --git a/scripts/dtc/flattree.c b/scripts/dtc/flattree.c
> index 1bcd8089c5b9..156ca5da89b2 100644
> --- a/scripts/dtc/flattree.c
> +++ b/scripts/dtc/flattree.c
> @@ -222,9 +222,7 @@ static int stringtable_insert(struct data *d, const char *str)
>  {
>         unsigned int i;
>
> -       /* FIXME: do this more efficiently? */
> -
> -       for (i = 0; i < d->len; i++) {
> +       for (i = 0; i < d->len; i += strlen(d->val + i) + 1) {

This isn't equivalent. If 'd' was 'foobar' and 'str' was 'bar', then
before we'd match. Now you don't.

>                 if (streq(str, d->val + i))
>                         return i;
>         }
> --
> 2.50.1
>