Message-ID: <55425ADA.4060105@goop.org>
Date: Thu, 30 Apr 2015 09:39:54 -0700
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: Juergen Gross <jgross@suse.com>, linux-kernel@vger.kernel.org,
        x86@kernel.org, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com,
        xen-devel@lists.xensource.com, konrad.wilk@oracle.com,
        david.vrabel@citrix.com, boris.ostrovsky@oracle.com,
        chrisw@sous-sol.org, akataria@vmware.com, rusty@rustcorp.com.au,
        virtualization@lists.linux-foundation.org, gleb@kernel.org,
        pbonzini@redhat.com, kvm@vger.kernel.org
Subject: Re: [PATCH 0/6] x86: reduce paravirtualized spinlock overhead
References: <1430391243-7112-1-git-send-email-jgross@suse.com>
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On 04/30/2015 03:53 AM, Juergen Gross wrote:
> Paravirtualized spinlocks produce some overhead even if the kernel is
> running on bare metal. The main reason are the more complex locking
> and unlocking functions. Especially unlocking is no longer just one
> instruction but so complex that it is no longer inlined.
>
> This patch series addresses this issue by adding two more pvops
> functions to reduce the size of the inlined spinlock functions. When
> running on bare metal unlocking is again basically one instruction.

Out of curiosity, is there a measurable difference?

    J

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