From: sashiko-bot@kernel.org
To: "Michal Pluta" <michalpl2003@gmail.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 3/5] perf symbol: Grow the Rust demangle buffer geometrically
Date: Mon, 28 Sep 2026 01:08:56 +0000 [thread overview]
Message-ID: <20260928010857.50C001F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260928010227.1903673-4-michalpl2003@gmail.com>
> When a demangled Rust name doesn't fit in the provided buffer,
> dso__demangle_sym() adds 32 bytes to it and formats the name again from
> the start. The number of attempts grows with the length of the output,
> so the total work is quadratic. Names with deeply nested generic types
> need many attempts, leading to noticeable slowdowns in larger programs.
>
> Double the buffer instead, reaching the maximum buffer limit exactly
> rather than stopping 32 bytes early. The demangled names are
> unchanged.
>
> Add a test for a symbol whose expansion exceeds the bound.
>
> Signed-off-by: Michal Pluta <michalpl2003@gmail.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260928010227.1903673-1-michalpl2003@gmail.com?part=3
next prev parent reply other threads:[~2026-09-28 1:08 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-28 1:02 [PATCH 0/5] perf symbol: Speed up demangling of long Rust symbols Michal Pluta
2026-09-28 1:02 ` [PATCH 1/5] perf test demangle: Fail when demangling fails Michal Pluta
2026-09-28 1:07 ` sashiko-bot
2026-09-28 21:31 ` Ian Rogers
2026-09-28 1:02 ` [PATCH 2/5] perf symbol: Don't return an unterminated Rust demangle buffer Michal Pluta
2026-09-28 1:06 ` sashiko-bot
2026-09-28 21:33 ` Ian Rogers
2026-09-30 17:10 ` Arnaldo Carvalho de Melo
2026-09-28 1:02 ` [PATCH 3/5] perf symbol: Grow the Rust demangle buffer geometrically Michal Pluta
2026-09-28 1:08 ` sashiko-bot [this message]
2026-09-28 21:43 ` Ian Rogers
2026-10-06 20:06 ` Namhyung Kim
2026-10-09 2:22 ` Michal Pluta
2026-10-09 20:39 ` Ian Rogers
2026-09-28 1:02 ` [PATCH 4/5] perf symbol: Shrink the demangled Rust buffer to fit Michal Pluta
2026-09-28 1:07 ` sashiko-bot
2026-10-06 20:07 ` Namhyung Kim
2026-09-28 1:02 ` [PATCH 5/5] perf symbol: Move Rust demangling into its own function Michal Pluta
2026-09-28 1:07 ` sashiko-bot
2026-10-06 20:10 ` [PATCH 0/5] perf symbol: Speed up demangling of long Rust symbols Namhyung Kim
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