From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Luis Chamberlain <mcgrof@kernel.org>
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: Fri, 9 Sep 2022 09:17:28 +0800 [thread overview]
Message-ID: <0e662541-baf8-1074-06bd-1398bdf7c2a7@huawei.com> (raw)
In-Reply-To: <YxqDyyVwVUnqc8B1@bombadil.infradead.org>
On 2022/9/9 8:07, Luis Chamberlain wrote:
> 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"?
Good advice. I'll write it today.
>
> Luis
> .
>
--
Regards,
Zhen Lei
prev parent reply other threads:[~2022-09-09 1:17 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 ` [PATCH 0/7] kallsyms: Optimizes the performance of lookup symbols Luis Chamberlain
2022-09-09 1:17 ` Leizhen (ThunderTown) [this message]
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