From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Sheng Yang <sheng@linux.intel.com>
Cc: Ian Campbell <Ian.Campbell@eu.citrix.com>,
Ian Pratt <Ian.Pratt@eu.citrix.com>,
xen-devel <xen-devel@lists.xensource.com>,
Tim Deegan <Tim.Deegan@citrix.com>,
Keir Fraser <Keir.Fraser@eu.citrix.com>
Subject: Re: Re: [PATCH][v4] PV extension of HVM(hybrid) support in Xen
Date: Mon, 01 Mar 2010 20:39:34 -0800 [thread overview]
Message-ID: <4B8C9686.40608@goop.org> (raw)
In-Reply-To: <201003021136.02590.sheng@linux.intel.com>
On 03/01/2010 07:36 PM, Sheng Yang wrote:
>> static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow)
>> {
>> u64 delta = native_read_tsc() - shadow->tsc_timestamp;
>> return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow-
>> tsc_shift);
>> }
>>
> tsc_timestamp take the vcpu beginning at 0, so that's the assumption.
Why would it be 0? Xen sets tsc_timestamp to the current tsc when it
updates the time parameters, which is whenever the vcpu is scheduled on
a pcpu (and other times). There's no expectation that the tsc starts
from 0, since that won't ever be the case.
J
next prev parent reply other threads:[~2010-03-02 4:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-01 9:43 [PATCH][v4] PV extension of HVM(hybrid) support in Xen Sheng Yang
2010-03-01 10:00 ` Keir Fraser
2010-03-01 10:52 ` Stefano Stabellini
2010-03-01 10:21 ` Tim Deegan
2010-03-01 11:40 ` Sheng Yang
2010-03-02 1:49 ` Jeremy Fitzhardinge
2010-03-02 3:36 ` Sheng Yang
2010-03-02 4:39 ` Jeremy Fitzhardinge [this message]
2010-03-02 5:04 ` Sheng Yang
2010-03-02 5:21 ` Jeremy Fitzhardinge
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