From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9DDC3CB541; Wed, 30 Sep 2026 06:26:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790749570; cv=none; b=qt3lUEQgUEjGBW4UekU4cJn89/gZ15zEfpw9TlY9A1LGqxLihoGFghwBOBXKp0YhcqqT8LboYp4YxbjaLmgzK2NXjVafhPgdUikZPAQuxEzBiWBIOVisgOL4S5RHSOC0jA/l+bop62QpvOnf9poDHeJR9jTg1+P5uXJJPIpvKxM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790749570; c=relaxed/simple; bh=0NvyQ7Lhy0zOc+2x5j45PfQS7hAYHpnenIM4jeWcRLs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=u4MqHEEKsrnjsxIB+nc5oyOOLkYw/gwT2uTRKbI0s3reJZ5TtOQq9cykVp6x2oYAakjlPWw+ueiekZdud4eAf4HYunj40c8DLx4rom9aa5+FyhYc5E6IDvaiUJbc/sz5UdBw9/DTJNaroJ3D1PNcR5aOxQLyQJEVfZxRjkgcycE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NLqB/OqO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NLqB/OqO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A0441F000FF; Wed, 30 Sep 2026 06:26:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790749567; bh=W6CVv6netXtQi2yXCagH7cZ+eCADzZUg5oVn2dFur6E=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=NLqB/OqOnfmkUYiYtPwMw1Oja5FurkIhi15w23bbPMuye9dM+w7b+UJvg8Lb1gCES +Q0Wm93LzxpLakuFDlcUXN8+l8B1qWg6vvLfpvRVPFZ9NEDWR8OzTh4uvpAWrgAray IFdZaJbJp7tA8k4km3SoKTRaE8dKTC6v8LxBT+ghvKCvSZ8loUG1ar/aMy1a0Lixp5 0lsA8R6SUdJsRkudpo8O9SOlVzNkHE6NbwVjnyr31NDQbM1Eb9TYShxZ1jIn6DnBWF kr9b23dSSz7lE29jOBGrYObY3qvkSATBjdTOf6aZn8secPofFZWzZSdfRxvTs7qEQ8 ALzj5mcKW/jtw== Date: Tue, 29 Sep 2026 23:26:06 -0700 From: Kees Cook To: jim.cromie@gmail.com Cc: Andrew Morton , Petr Mladek , Zhen Lei , Luis Chamberlain , Andrey Grodzovsky , Steven Rostedt , Lorenzo Stoakes , David Laight , Masahiro Yamada , Jiri Olsa , 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 Message-ID: <202609292325.7C5769454@keescook> References: <20260929-ksyms-tune-v7-0-be568ceef41e@gmail.com> <20260929-ksyms-tune-v7-1-be568ceef41e@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 Reviewed-by: Kees Cook This is a nice win with no downside. :) -- Kees Cook