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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Dmitry Safonov <dima@arista.com>, linux-kernel@vger.kernel.org
Cc:     Dmitry Safonov <0x7f454c46@gmail.com>,
        Andrei Vagin <avagin@gmail.com>,
        Adrian Reber <adrian@lisas.de>,
        Andrei Vagin <avagin@openvz.org>,
        Andy Lutomirski <luto@kernel.org>,
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        Shuah Khan <shuah@kernel.org>,
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        linux-api@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCHv8 02/34] lib/vdso: make do_hres and do_coarse as __always_inline
In-Reply-To: <ed2e65ae-75b0-ed79-0a95-90be6b82e6be@arm.com>
References: <20191112012724.250792-1-dima@arista.com> <20191112012724.250792-3-dima@arista.com> <ed2e65ae-75b0-ed79-0a95-90be6b82e6be@arm.com>
Date:   Fri, 10 Jan 2020 12:42:45 +0100
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Vincenzo Frascino <vincenzo.frascino@arm.com> writes:
> On 11/12/19 1:26 AM, Dmitry Safonov wrote:
>> +» » vd·=·&vd[CS_HRES_COARSE];
>> +out_hres:
>> +» » return·do_hres(vd,·clock,·ts);
>> » }·else·if·(msk·&·VDSO_COARSE)·{
>> » » do_coarse(&vd[CS_HRES_COARSE],·clock,·ts);
>> » » return·0;
>> » }·else·if·(msk·&·VDSO_RAW)·{
>> -» » return·do_hres(&vd[CS_RAW],·clock,·ts);
>> +» » vd·=·&vd[CS_RAW];
>> +» » /*·goto·allows·to·avoid·extra·inlining·of·do_hres.·*/
>> +» » goto·out_hres;
>
> What is the performance impact of "goto out_hres"?

On x86 it's invisible at least in my limited testing.

Thanks,

        tglx