From: Keir Fraser <keir.fraser@eu.citrix.com>
To: "dan.magenheimer@oracle.com" <dan.magenheimer@oracle.com>,
"Xen-Devel (E-mail)" <xen-devel@lists.xensource.com>
Cc: Dave Winchell <dwinchell@virtualiron.com>
Subject: Re: Xen system skew MUCH worse than tsc skew (was RE: RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasing hvm guest time))
Date: Mon, 21 Jul 2008 09:32:25 +0100 [thread overview]
Message-ID: <C4AA0829.245DF%keir.fraser@eu.citrix.com> (raw)
In-Reply-To: <20080719115130390.00000001344@djm-pc>
On 19/7/08 18:51, "Dan Magenheimer" <dan.magenheimer@oracle.com> wrote:
> Would you expect system load to impact stime skew between
> processors (using hpet as a system timer)? I can repeatably
> watch skew get worse when I am launching an hvm domain. It is
> MUCH worse when the new domain is in its early stages of booting.
> CPU load on domain0 has little or no impact but I/O load
> on dom0 seems to make skew get worse.
Perhaps it makes a difference if it takes each CPU a bit longer to execute
the calibration function in softirq context? That could be delayed by long
hypercalls, for example (although long hypercalls should mostly be
preemptible).
-- Keir
next prev parent reply other threads:[~2008-07-21 8:32 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-02 16:03 [PATCH] strictly increasing hvm guest time Dan Magenheimer
2008-07-02 16:07 ` Keir Fraser
2008-07-02 21:50 ` Dan Magenheimer
2008-07-02 22:41 ` [PATCH] record max stime skew (was RE: [PATCH] strictly increasing hvm guest time) Dan Magenheimer
2008-07-03 8:03 ` Keir Fraser
2008-07-03 16:24 ` Dan Magenheimer
2008-07-03 16:35 ` Dan Magenheimer
2008-07-03 20:03 ` Dan Magenheimer
2008-07-03 23:00 ` Keir Fraser
2008-07-04 15:11 ` Dan Magenheimer
2008-07-04 15:22 ` Keir Fraser
2008-07-04 19:32 ` Dan Magenheimer
2008-07-04 19:56 ` Keir Fraser
2008-07-10 0:24 ` Dan Magenheimer
2008-07-10 7:40 ` Keir Fraser
2008-07-10 22:42 ` Xen system skew MUCH worse than tsc skew (was RE: RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasing hvm guest time)) Dan Magenheimer
2008-07-11 8:27 ` Keir Fraser
2008-07-11 20:53 ` Dan Magenheimer
2008-07-11 21:27 ` Xen system skew MUCH worse than tsc skew (was RE: RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasinghvm " Ian Pratt
2008-07-12 21:05 ` Dan Magenheimer
2008-07-11 21:27 ` Xen system skew MUCH worse than tsc skew (was RE: RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasing hvm " Keir Fraser
2008-07-12 21:07 ` Dan Magenheimer
2008-07-19 17:51 ` Dan Magenheimer
2008-07-21 8:32 ` Keir Fraser [this message]
2008-07-22 22:27 ` Dan Magenheimer
2008-07-22 23:07 ` Xen system skew MUCH worse than tsc skew (was RE: RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasinghvm " Ian Pratt
2008-07-23 0:40 ` Dan Magenheimer
2008-07-23 1:16 ` Ian Pratt
2008-07-23 6:11 ` Tian, Kevin
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