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From: Thomas Shao <huishao@microsoft.com>
To: Olaf Hering <olaf@aepfle.de>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"driverdev-devel@linuxdriverproject.org" 
	<driverdev-devel@linuxdriverproject.org>,
	"apw@canonical.com" <apw@canonical.com>,
	"jasowang@redhat.com" <jasowang@redhat.com>,
	"KY Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>
Subject: RE: [PATCH] Drivers: hv: util: Implement Time Synchronization using host time sample
Date: Tue, 23 Sep 2014 09:47:59 +0000	[thread overview]
Message-ID: <CD2CABCB2C0A0D4682C5F8AD8401415408E2A9@HKXPRD3002MB006.064d.mgd.msft.net> (raw)
In-Reply-To: <20140923075610.GA10933@aepfle.de>

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> -----Original Message-----
> From: Olaf Hering [mailto:olaf@aepfle.de]
> Sent: Tuesday, September 23, 2014 3:56 PM
> To: Thomas Shao
> Cc: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org;
> driverdev-devel@linuxdriverproject.org; apw@canonical.com;
> jasowang@redhat.com; KY Srinivasan; Haiyang Zhang
> Subject: Re: [PATCH] Drivers: hv: util: Implement Time Synchronization using
> host time sample
> 
> On Tue, Sep 23, Thomas Shao wrote:
> 
> > In current hyper-v time sync service,it only gets the initial clock
> > time from the host. It didn't process the following time samples. This
> > change introduced a module parameter called host_time_sync. If it is
> > set to true, the guest will periodically sychronize it's time with the
> > host clock using host time sample. By default it is disabled, because
> > we still recommend user to configure NTP for time synchronization.
> 
> Is that new knob a temporary thing to aid testing and development?
> Because once it sneaks in it becomes some sort of ABIT.
> So if the outcome of all that is that 'sync with host every once in a while' will be
> the default, the new knob is not required.
> 

Hi Olaf, 
If the guest is configured with other time sync source, like NTP, we don't want the 
guest to periodically sync with host. This feature is useful when the guest didn't have
Internet connection to setup NTP. So the new knob is to allow users to only turn on the
host-guest sync when they need.

Regards
Thomas

> Olaf
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WARNING: multiple messages have this Message-ID (diff)
From: Thomas Shao <huishao@microsoft.com>
To: Olaf Hering <olaf@aepfle.de>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"driverdev-devel@linuxdriverproject.org"
	<driverdev-devel@linuxdriverproject.org>,
	"apw@canonical.com" <apw@canonical.com>,
	"jasowang@redhat.com" <jasowang@redhat.com>,
	KY Srinivasan <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>
Subject: RE: [PATCH] Drivers: hv: util: Implement Time Synchronization using host time sample
Date: Tue, 23 Sep 2014 09:47:59 +0000	[thread overview]
Message-ID: <CD2CABCB2C0A0D4682C5F8AD8401415408E2A9@HKXPRD3002MB006.064d.mgd.msft.net> (raw)
In-Reply-To: <20140923075610.GA10933@aepfle.de>


> -----Original Message-----
> From: Olaf Hering [mailto:olaf@aepfle.de]
> Sent: Tuesday, September 23, 2014 3:56 PM
> To: Thomas Shao
> Cc: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org;
> driverdev-devel@linuxdriverproject.org; apw@canonical.com;
> jasowang@redhat.com; KY Srinivasan; Haiyang Zhang
> Subject: Re: [PATCH] Drivers: hv: util: Implement Time Synchronization using
> host time sample
> 
> On Tue, Sep 23, Thomas Shao wrote:
> 
> > In current hyper-v time sync service,it only gets the initial clock
> > time from the host. It didn't process the following time samples. This
> > change introduced a module parameter called host_time_sync. If it is
> > set to true, the guest will periodically sychronize it's time with the
> > host clock using host time sample. By default it is disabled, because
> > we still recommend user to configure NTP for time synchronization.
> 
> Is that new knob a temporary thing to aid testing and development?
> Because once it sneaks in it becomes some sort of ABIT.
> So if the outcome of all that is that 'sync with host every once in a while' will be
> the default, the new knob is not required.
> 

Hi Olaf, 
If the guest is configured with other time sync source, like NTP, we don't want the 
guest to periodically sync with host. This feature is useful when the guest didn't have
Internet connection to setup NTP. So the new knob is to allow users to only turn on the
host-guest sync when they need.

Regards
Thomas

> Olaf

  reply	other threads:[~2014-09-23 10:03 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-23  5:44 [PATCH] Drivers: hv: util: Implement Time Synchronization using host time sample Thomas Shao
2014-09-23  7:56 ` Olaf Hering
2014-09-23  7:56   ` Olaf Hering
2014-09-23  9:47   ` Thomas Shao [this message]
2014-09-23  9:47     ` Thomas Shao
2014-09-25  6:07   ` Sitsofe Wheeler
2014-09-25  9:40     ` Thomas Shao
2014-09-25  9:40       ` Thomas Shao
2014-09-25 13:28       ` Time keeps on slipping... on Hyper-V Sitsofe Wheeler
2014-09-25 13:28         ` Sitsofe Wheeler
2014-09-26  6:57         ` Thomas Shao
2014-09-26  6:57           ` Thomas Shao
2014-09-26  9:24           ` Mike Surcouf
2014-09-26  9:24             ` Mike Surcouf
2014-09-26  9:46             ` Thomas Shao
2014-09-26  9:46               ` Thomas Shao
2014-09-26 10:02 [PATCH] Drivers: hv: util: Implement Time Synchronization using host time sample Thomas Shao
2014-09-26 11:53 ` Mike Surcouf
2014-09-26 11:53   ` Mike Surcouf
2014-09-26 12:30   ` Thomas Shao
2014-09-26 12:30     ` Thomas Shao
2014-09-26 13:07     ` Mike Surcouf
2014-09-26 13:07       ` Mike Surcouf
2014-09-26 13:52       ` Mike Surcouf
2014-09-26 13:52         ` Mike Surcouf
2014-09-26 15:13         ` Thomas Shao
2014-09-26 15:13           ` Thomas Shao

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