From: "Jan Beulich" <JBeulich@suse.com>
To: "Paul Durrant" <paul.durrant@citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
xen-devel <xen-devel@lists.xenproject.org>, WeiLiu <wl@xen.org>,
Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH v2] viridian: unify time sources
Date: Fri, 21 Jun 2019 09:08:29 -0600 [thread overview]
Message-ID: <5D0CF2ED020000780023A323@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <20190617082358.2734-1-paul.durrant@citrix.com>
>>> On 17.06.19 at 10:23, <paul.durrant@citrix.com> wrote:
> Currently, the time_ref_count enlightened time source maintains an offset
> such that time is frozen when the domain paused, but the reference_tsc
> enlightened time source does not. After migrate, the reference_tsc source
> may become invalidated (e.g. because of host cpu frequency mismatch) which
> will cause Windows to fall back to time_ref_count. Thus, the guest will
> observe a jump in time equivalent to the offset.
>
> This patch unifies the two enlightened time sources such that the same
> offset applies to both of them. Also, it's not really necessary to have
> two different functions to calculating a 10MHz counter value, time_now() and
> raw_trc_val(), so this patch removes the latter implementation. The
> unification also allows removal of the reference_tsc_valid flag.
>
> Whilst in the area, this patch also takes the opportunity to constify a few
> pointers which were missed in earlier patches.
>
> Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
This looks okay to me now, but I don't feel qualified to give an R-b.
While not strictly applicable for a file maintained by you,
Acked-by: Jan Beulich <jbeulich@suse.com>
will have to do here.
Jan
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prev parent reply other threads:[~2019-06-21 15:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-17 8:23 [Xen-devel] [PATCH v2] viridian: unify time sources Paul Durrant
2019-06-20 8:44 ` Paul Durrant
2019-06-21 13:49 ` Alexandru Stefan ISAILA
2019-06-21 13:58 ` Paul Durrant
2019-06-21 15:20 ` Jan Beulich
2019-06-21 15:21 ` Paul Durrant
2019-06-21 15:08 ` Jan Beulich [this message]
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