From: Kees Cook <kees@kernel.org>
To: jim.cromie@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>,
Petr Mladek <pmladek@suse.com>,
Zhen Lei <thunder.leizhen@huawei.com>,
Luis Chamberlain <mcgrof@kernel.org>,
Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>,
Steven Rostedt <rostedt@goodmis.org>,
Lorenzo Stoakes <ljs@kernel.org>,
David Laight <david.laight.linux@gmail.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Jiri Olsa <olsajiri@gmail.com>,
linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
bpf@vger.kernel.org
Subject: Re: [PATCH v7 1/3] kallsyms: Match compressed tokens on the fly during binary search
Date: Tue, 29 Sep 2026 23:26:06 -0700 [thread overview]
Message-ID: <202609292325.7C5769454@keescook> (raw)
In-Reply-To: <20260929-ksyms-tune-v7-1-be568ceef41e@gmail.com>
On Tue, Sep 29, 2026 at 12:07:30PM -0600, Jim Cromie via B4 Relay wrote:
> So we introduce kallsyms_strcmp_symbol() to compare ASCII search_name
> against tokenized symbols on the fly. Like strcmp, it tests the
> strings char by char, but when it hits a token in the symbol-string,
> it continues the char-test against that token-string, which is in
> kallsyms_token_table[]. It returns +- on 1st mismatch.
>
> Measured across all ~184k symbols via CONFIG_KALLSYMS_SELFTEST, this
> shaves ~530 ns (~14%) off average kallsyms_lookup_name() latency (from
> ~3810 ns to ~3280 ns on the default 256:1 baseline) and drops the
> 512-byte namebuf buffer stack-alloc in kallsyms_lookup_names().
>
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Kees Cook <kees@kernel.org>
This is a nice win with no downside. :)
--
Kees Cook
next prev parent reply other threads:[~2026-09-30 6:26 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-29 18:07 [PATCH v7 0/3] kallsyms: Accelerate symbol name lookups by ~7x Jim Cromie via B4 Relay
2026-09-29 18:07 ` Jim Cromie
2026-09-29 18:07 ` [PATCH v7 1/3] kallsyms: Match compressed tokens on the fly during binary search Jim Cromie via B4 Relay
2026-09-29 18:07 ` Jim Cromie
2026-09-30 1:17 ` bot+bpf-ci
2026-09-30 6:26 ` Kees Cook [this message]
2026-09-29 18:07 ` [PATCH v7 2/3] kallsyms: Increase marker density to 16:1 to accelerate lookups Jim Cromie via B4 Relay
2026-09-29 18:07 ` Jim Cromie
2026-09-30 6:28 ` Kees Cook
2026-09-29 18:07 ` [PATCH v7 3/3] kallsyms: Unroll 24-bit sequence reconstruction in get_symbol_seq() Jim Cromie via B4 Relay
2026-09-29 18:07 ` Jim Cromie
2026-09-30 6:56 ` Kees Cook
2026-09-30 9:13 ` David Laight
2026-09-29 18:45 ` [PATCH v7 0/3] kallsyms: Accelerate symbol name lookups by ~7x Andrew Morton
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