From: Sean Christopherson <seanjc@google.com>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v4 5/5] KVM: LAPIC: Narrow the timer latency between wait_lapic_expire and world switch
Date: Tue, 18 May 2021 19:13:58 +0000 [thread overview]
Message-ID: <YKQR9rq9WNT6dauh@google.com> (raw)
In-Reply-To: <1621339235-11131-5-git-send-email-wanpengli@tencent.com>
On Tue, May 18, 2021, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> Let's treat lapic_timer_advance_ns automatic tuning logic as hypervisor
> overhead, move it before wait_lapic_expire instead of between wait_lapic_expire
> and the world switch, the wait duration should be calculated by the
> up-to-date guest_tsc after the overhead of automatic tuning logic. This
> patch reduces ~30+ cycles for kvm-unit-tests/tscdeadline-latency when testing
> busy waits.
>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
Reviewed-by: Sean Christopherson <seanjc@google.com>
next prev parent reply other threads:[~2021-05-18 19:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-18 12:00 [PATCH v4 1/5] KVM: exit halt polling on need_resched() for both book3s and generic halt-polling Wanpeng Li
2021-05-18 12:00 ` [PATCH v4 2/5] KVM: X86: Bail out of direct yield in case of under-committed scenarios Wanpeng Li
2021-05-18 19:21 ` Sean Christopherson
2021-05-19 2:57 ` Wanpeng Li
2021-05-24 13:42 ` Paolo Bonzini
2021-05-24 13:47 ` Wanpeng Li
2021-05-18 12:00 ` [PATCH v4 3/5] KVM: X86: Fix vCPU preempted state from guest's point of view Wanpeng Li
2021-05-18 12:00 ` [PATCH v4 4/5] KVM: X86: hyper-v: Task srcu lock when accessing kvm_memslots() Wanpeng Li
2021-05-18 12:00 ` [PATCH v4 5/5] KVM: LAPIC: Narrow the timer latency between wait_lapic_expire and world switch Wanpeng Li
2021-05-18 19:13 ` Sean Christopherson [this message]
2021-05-24 13:46 ` [PATCH v4 1/5] KVM: exit halt polling on need_resched() for both book3s and generic halt-polling Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YKQR9rq9WNT6dauh@google.com \
--to=seanjc@google.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kernellwp@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.