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From:   Eric Lin <eric.lin@sifive.com>
Date:   Tue, 18 Jan 2022 12:05:45 +0800
Message-ID: <CAPqJEFoUyHiyNj8Hx-wRaw86NLb5hGo-WT4ysqV4RGerYyDyJA@mail.gmail.com>
Subject: About perf tool set exclude_guest = 1 on guest environment
To:     linux-kernel@vger.kernel.org, namhyung@kernel.org,
        jolsa@redhat.com, alexander.shishkin@linux.intel.com,
        mark.rutland@arm.com, acme@kernel.org, mingo@redhat.com,
        peterz@infradead.org, yao.jin@linux.intel.com
Cc:     Greentime Hu <greentime.hu@sifive.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Vincent Chen <vincent.chen@sifive.com>
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Hi all,

Currently, I run the perf command 'perf record -e branches:u ls'  and
'perf record -e branches ls'. It will set exclude_guest = 1 as below:

# perf record -e branches:u ls
# perf evlist -v
branches:u: .., exclude_kernel: 1, exclude_hv: 1,, exclude_guest: 1, ..

# perf record -e branches ls
# perf evlist -v
branches: ..., exclude_guest: 1, ...

As I understand it, set exclude_guest =1 will not include guest counting.
May I ask if I run the above commands as a guest user, should the
architecture implementation ignore this exclude_guest flags and still
make perf can count guest events in Linux kernel?

Best regards,
Eric Lin