From: Luis Chamberlain <mcgrof@kernel.org>
To: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
Petr Mladek <pmladek@suse.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Masahiro Yamada <masahiroy@kernel.org>,
Alexei Starovoitov <ast@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-modules@vger.kernel.org
Subject: Re: [PATCH 0/7] kallsyms: Optimizes the performance of lookup symbols
Date: Thu, 8 Sep 2022 17:07:39 -0700 [thread overview]
Message-ID: <YxqDyyVwVUnqc8B1@bombadil.infradead.org> (raw)
In-Reply-To: <20220908130936.674-1-thunder.leizhen@huawei.com>
On Thu, Sep 08, 2022 at 09:09:29PM +0800, Zhen Lei wrote:
> Currently, to search for a symbol, we need to expand the symbols in
> 'kallsyms_names' one by one, and then use the expanded string for
> comparison. This is very slow.
>
> In fact, we can first compress the name being looked up and then use
> it for comparison when traversing 'kallsyms_names'.
>
> This patch series optimizes the performance of function kallsyms_lookup_name(),
> and function klp_find_object_symbol() in the livepatch module. Based on the
> test results, the performance overhead is reduced to 5%. That is, the
> performance of these functions is improved by 20 times.
>
> To avoid increasing the kernel size in non-debug mode, the optimization is only
> for the case CONFIG_KALLSYMS_ALL=y.
WIthout having time yet to reveiw the implementation details, it would
seem this is an area we may want to test for future improvements easily,
so a selftest better yet a kunit test may be nice for this. Can you
write one so we can easily gather a simple metric for "how long does
this take"?
Luis
next prev parent reply other threads:[~2022-09-09 0:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-08 13:09 [PATCH 0/7] kallsyms: Optimizes the performance of lookup symbols Zhen Lei
2022-09-08 13:09 ` [PATCH 1/7] scripts/kallsyms: don't compress symbol type when CONFIG_KALLSYMS_ALL=y Zhen Lei
2022-09-08 13:09 ` [PATCH 2/7] scripts/kallsyms: rename build_initial_tok_table() Zhen Lei
2022-09-08 13:09 ` [PATCH 3/7] kallsyms: Adjust the types of some local variables Zhen Lei
2022-09-08 13:09 ` [PATCH 4/7] kallsyms: Improve the performance of kallsyms_lookup_name() Zhen Lei
2022-09-08 13:09 ` [PATCH 5/7] kallsyms: Add helper kallsyms_on_each_match_symbol() Zhen Lei
2022-09-08 13:09 ` [PATCH 6/7] livepatch: Use kallsyms_on_each_match_symbol() to improve performance Zhen Lei
2022-09-08 13:09 ` [PATCH 7/7] livepatch: Improve the search performance of module_kallsyms_on_each_symbol() Zhen Lei
2022-09-09 0:07 ` Luis Chamberlain [this message]
2022-09-09 1:17 ` [PATCH 0/7] kallsyms: Optimizes the performance of lookup symbols Leizhen (ThunderTown)
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