From: Avi Kivity <avi@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: "agraf@suse.de" <agraf@suse.de>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [Qemu-devel] [PATCH 1/4] xen: introduce mc146818rtcxen
Date: Sun, 20 Nov 2011 16:53:34 +0200 [thread overview]
Message-ID: <4EC9146E.1070608@redhat.com> (raw)
In-Reply-To: <4EC671AF.5030805@codemonkey.ws>
On 11/18/2011 04:54 PM, Anthony Liguori wrote:
>
> Thinking more about it, I think this entire line of thinking is wrong
> (including mine) :-)
>
> The problem you're trying to solve is that the RTC fires two 1 second
> timers regardless of whether the guest is reading the wall clock time,
> right? And since wall clock time is never read from the QEMU RTC in
> Xen, it's a huge waste?
>
> The Right Solution would be to modify the RTC emulation such that it
> did a qemu_get_clock() during read of the CMOS registers in order to
> ensure the time was up to date (instead of using 1 second timers).
>
> Then the timers wouldn't even exist anymore.
That would make host time adjustments (suspend/resume) be reflected in
the guest.
Not sure if that's good or bad, but it's different.
--
error compiling committee.c: too many arguments to function
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: "agraf@suse.de" <agraf@suse.de>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [PATCH 1/4] xen: introduce mc146818rtcxen
Date: Sun, 20 Nov 2011 16:53:34 +0200 [thread overview]
Message-ID: <4EC9146E.1070608@redhat.com> (raw)
In-Reply-To: <4EC671AF.5030805@codemonkey.ws>
On 11/18/2011 04:54 PM, Anthony Liguori wrote:
>
> Thinking more about it, I think this entire line of thinking is wrong
> (including mine) :-)
>
> The problem you're trying to solve is that the RTC fires two 1 second
> timers regardless of whether the guest is reading the wall clock time,
> right? And since wall clock time is never read from the QEMU RTC in
> Xen, it's a huge waste?
>
> The Right Solution would be to modify the RTC emulation such that it
> did a qemu_get_clock() during read of the CMOS registers in order to
> ensure the time was up to date (instead of using 1 second timers).
>
> Then the timers wouldn't even exist anymore.
That would make host time adjustments (suspend/resume) be reflected in
the guest.
Not sure if that's good or bad, but it's different.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-11-20 14:53 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-15 14:48 [Qemu-devel] [PATCH 0/4] prevent Qemu from waking up needlessly Stefano Stabellini
2011-11-15 14:48 ` Stefano Stabellini
2011-11-15 14:51 ` [Qemu-devel] [PATCH 1/4] xen: introduce mc146818rtcxen stefano.stabellini
2011-11-15 14:51 ` stefano.stabellini
2011-11-15 14:54 ` [Qemu-devel] " Anthony Liguori
2011-11-15 14:54 ` Anthony Liguori
2011-11-15 16:57 ` [Qemu-devel] " Stefano Stabellini
2011-11-18 11:46 ` Stefano Stabellini
2011-11-18 11:46 ` Stefano Stabellini
2011-11-18 13:58 ` [Qemu-devel] " Anthony Liguori
2011-11-18 13:58 ` Anthony Liguori
2011-11-18 14:54 ` [Qemu-devel] " Anthony Liguori
2011-11-18 14:54 ` Anthony Liguori
2011-11-20 14:53 ` Avi Kivity [this message]
2011-11-20 14:53 ` Avi Kivity
2011-11-21 20:49 ` [Qemu-devel] " Anthony Liguori
2011-11-21 20:49 ` Anthony Liguori
2011-11-21 11:05 ` [Qemu-devel] " Stefano Stabellini
2011-11-21 11:05 ` Stefano Stabellini
2011-11-21 13:21 ` [Qemu-devel] " Paolo Bonzini
2011-11-21 13:21 ` Paolo Bonzini
2011-11-15 14:51 ` [Qemu-devel] [PATCH 2/4] xen: do not initialize the interval timer emulator stefano.stabellini
2011-11-15 14:51 ` stefano.stabellini
2011-11-15 14:51 ` [Qemu-devel] [PATCH 3/4] xen: introduce an event channel for buffered io event notifications stefano.stabellini
2011-11-15 14:51 ` stefano.stabellini
2011-11-15 17:13 ` [Qemu-devel] [Xen-devel] " Ian Campbell
2011-11-15 17:13 ` Ian Campbell
2011-11-15 17:20 ` [Qemu-devel] " Stefano Stabellini
2011-11-15 17:20 ` Stefano Stabellini
2011-11-15 17:24 ` [Qemu-devel] " Ian Campbell
2011-11-15 17:24 ` Ian Campbell
2011-11-15 14:51 ` [Qemu-devel] [PATCH 4/4] qemu_calculate_timeout: increase minimum timeout to 1h stefano.stabellini
2011-11-15 14:51 ` stefano.stabellini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4EC9146E.1070608@redhat.com \
--to=avi@redhat.com \
--cc=agraf@suse.de \
--cc=anthony@codemonkey.ws \
--cc=qemu-devel@nongnu.org \
--cc=stefano.stabellini@eu.citrix.com \
--cc=xen-devel@lists.xensource.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.