From: linmiaohe <linmiaohe@huawei.com>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: "hpa@zytor.com" <hpa@zytor.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"rkrcmar@redhat.com" <rkrcmar@redhat.com>,
"sean.j.christopherson@intel.com"
<sean.j.christopherson@intel.com>,
"vkuznets@redhat.com" <vkuznets@redhat.com>,
"jmattson@google.com" <jmattson@google.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"bp@alien8.de" <bp@alien8.de>
Subject: Re: [PATCH] KVM: x86: small optimization for is_mtrr_mask calculation
Date: Fri, 6 Mar 2020 02:30:17 +0000 [thread overview]
Message-ID: <9063b8c3e1664c72b05ea92865f88c68@huawei.com> (raw)
Wanpeng Li <kernellwp@gmail.com> wrote:
>On Fri, 6 Mar 2020 at 10:23, linmiaohe <linmiaohe@huawei.com> wrote:
>>
>> hpa@zytor.com wrote:
>> >>On March 5, 2020 6:05:40 PM PST, linmiaohe <linmiaohe@huawei.com> wrote:
>> >>Hi,
>> >>Paolo Bonzini <pbonzini@redhat.com> wrote:
>> >>Many thanks for suggestion. What do you mean is like this ?
>> >>
>> >> index = (msr - 0x200) >> 1;
>> >> is_mtrr_mask = msr & 1;
>> >>
>> >>Thanks again.
>> >
>> >You realize that the compiler will probably produce exactly the same code, right? As such, it is about making the code easy for the human reader.
>> >
>> >Even if it didn't, this code is as far from performance critical as one can possibly get.
>>
>> Yep, it looks gain little. Thanks.
>
>Please post the performance number when you mention optimize XXX later.
>
Sure, I would take care of this. Thanks for your reminder!
next reply other threads:[~2020-03-06 2:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-06 2:30 linmiaohe [this message]
-- strict thread matches above, loose matches on Subject: below --
2020-03-06 2:22 linmiaohe
2020-03-06 2:27 ` Wanpeng Li
2020-03-06 2:05 linmiaohe
2020-03-06 2:09 ` hpa
2020-03-05 2:48 linmiaohe
2020-03-05 14:35 ` Paolo Bonzini
2020-03-05 15:10 ` David Laight
2020-03-05 15:25 ` Paolo Bonzini
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