From: Keir Fraser <keir.fraser@eu.citrix.com>
To: "Jiang, Yunhong" <yunhong.jiang@intel.com>,
Dan Magenheimer <dan.magenheimer@oracle.com>,
"Xen-Devel (xen-devel@lists.xensource.com)"
<xen-devel@lists.xensource.com>, Ian Pratt <Ian.Pr>
Subject: Re: [RFC] Physical hot-add cpus and TSC
Date: Thu, 27 May 2010 09:44:04 +0100 [thread overview]
Message-ID: <C823EF64.1603B%keir.fraser@eu.citrix.com> (raw)
In-Reply-To: <789F9655DD1B8F43B48D77C5D30659731E78D370@shsmsx501.ccr.corp.intel.com>
On 27/05/2010 07:15, "Jiang, Yunhong" <yunhong.jiang@intel.com> wrote:
>>>> get synced up before host software gets a look in. I don't think we can
>>>> comment on whether or not there is an issue here without more
>>>> information.
>
> Yes, this is a issue. The TSC will not be synched by firmware when hot-added,
> at least I didn't find any spec on this, and my experiment shows the TSC value
> is very small when new CPU is brought up. We need sync it in Xen side,
>
> Is it possible to sync the new-added CPU with the BSP when the CPU is added
> (changed from non-present to present), as Keir suggested in previous mail? I
> will have a look on the related code.
I implemented this as xen-unstable:21468. This represents a strict
improvement on what was in xen-unstable before that (no tsc sync at all,
ever, because I deleted it about a week ago). Open to further improvements,
if we can get consensus.
-- Keir
next prev parent reply other threads:[~2010-05-27 8:44 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-26 15:19 [RFC] Physical hot-add cpus and TSC Dan Magenheimer
2010-05-26 15:45 ` Keir Fraser
2010-05-26 16:44 ` Dan Magenheimer
2010-05-26 17:02 ` Ian Pratt
2010-05-26 17:29 ` Keir Fraser
2010-05-26 17:39 ` Dan Magenheimer
2010-05-26 17:51 ` Keir Fraser
2010-05-26 18:01 ` Keir Fraser
2010-05-26 19:46 ` Dan Magenheimer
2010-05-26 21:26 ` Keir Fraser
2010-05-27 6:15 ` Jiang, Yunhong
2010-05-27 6:57 ` Keir Fraser
2010-05-27 7:09 ` Jiang, Yunhong
2010-05-27 7:15 ` Jiang, Yunhong
2010-05-27 19:55 ` Dan Magenheimer
2010-05-27 8:44 ` Keir Fraser [this message]
2010-05-27 9:31 ` Jiang, Yunhong
2010-05-27 15:08 ` Dan Magenheimer
2010-05-28 5:39 ` Jiang, Yunhong
2010-05-28 5:47 ` Keir Fraser
2010-05-28 6:29 ` Jiang, Yunhong
2010-05-28 7:03 ` Keir Fraser
2010-05-28 14:35 ` Dan Magenheimer
2010-05-28 15:33 ` Jiang, Yunhong
2010-05-28 16:25 ` Dan Magenheimer
2010-05-31 8:56 ` Jiang, Yunhong
2010-05-28 16:08 ` Keir Fraser
2010-05-28 16:36 ` Dan Magenheimer
2010-05-28 17:19 ` Keir Fraser
2010-05-28 14:52 ` Dan Magenheimer
2010-05-28 15:05 ` Jiang, Yunhong
2010-05-28 20:24 ` Dan Magenheimer
2010-05-31 7:54 ` Jiang, Yunhong
2010-06-01 0:30 ` Dan Magenheimer
2010-06-01 1:40 ` Jiang, Yunhong
2010-06-01 17:07 ` Jeremy Fitzhardinge
2010-06-02 9:17 ` Jiang, Yunhong
2010-06-10 6:55 ` Dong, Eddie
2010-06-10 13:15 ` Dan Magenheimer
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