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Date:   Wed, 18 Jan 2023 15:10:32 +0100
From:   Petr Mladek <pmladek@suse.com>
To:     Jiri Olsa <jolsa@kernel.org>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Josh Poimboeuf <jpoimboe@kernel.org>,
        Jiri Kosina <jikos@kernel.org>,
        Miroslav Benes <mbenes@suse.cz>,
        Zhen Lei <thunder.leizhen@huawei.com>, bpf@vger.kernel.org,
        live-patching@vger.kernel.org, linux-modules@vger.kernel.org,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>,
        Joe Lawrence <joe.lawrence@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Luis Chamberlain <mcgrof@kernel.org>
Subject: Re: [PATCHv3 bpf-next 3/3] bpf: Change modules resolving for kprobe
 multi link
Message-ID: <Y8f92N1AjLM0hYis@alley>
References: <20230116101009.23694-1-jolsa@kernel.org>
 <20230116101009.23694-4-jolsa@kernel.org>
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On Mon 2023-01-16 11:10:09, Jiri Olsa wrote:
> We currently use module_kallsyms_on_each_symbol that iterates all
> modules/symbols and we try to lookup each such address in user
> provided symbols/addresses to get list of used modules.
> 
> This fix instead only iterates provided kprobe addresses and calls
> __module_address on each to get list of used modules. This turned
> out ot be simpler and also bit faster.
> 
> On my setup with workload (executed 10 times):
> 
>    # test_progs -t kprobe_multi_bench_attach/modules
> 
> Current code:
> 
>  Performance counter stats for './test.sh' (5 runs):
> 
>     76,081,161,596      cycles:k                   ( +-  0.47% )
> 
>            18.3867 +- 0.0992 seconds time elapsed  ( +-  0.54% )
> 
> With the fix:
> 
>  Performance counter stats for './test.sh' (5 runs):
> 
>     74,079,889,063      cycles:k                   ( +-  0.04% )
> 
>            17.8514 +- 0.0218 seconds time elapsed  ( +-  0.12% )
> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>

The change looks good to me:

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr