From: "Jan Beulich" <JBeulich@suse.com>
To: "David Vrabel" <david.vrabel@citrix.com>
Cc: "John Stultz" <john.stultz@linaro.org>,
"Thomas Gleixner" <tglx@linutronix.de>, <xen-devel@lists.xen.org>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
<linux-kernel@vger.kernel.org>
Subject: Re: [Xen-devel] [PATCH 1/4] xen: disable non-boot VCPUs during suspend
Date: Thu, 20 Jun 2013 11:38:25 +0100 [thread overview]
Message-ID: <51C2F7C102000078000DF504@nat28.tlf.novell.com> (raw)
In-Reply-To: <1371655523-15609-2-git-send-email-david.vrabel@citrix.com>
>>> On 19.06.13 at 17:25, David Vrabel <david.vrabel@citrix.com> wrote:
> syscore_suspend() and syscore_resume() expect there to be only one
> online CPU. e.g., hrtimers_resume() only triggers events for the
> current CPU. Xen's suspend path was leaving all VCPUs online and then
> attempting to fixup problems afterwards (e.g., with an explicit call
> to clock_was_set() to trigger pending high resolution timers).
>
> Instead, disable non-boot CPUs before calling stop_machine() and
> reenable them afterwards.
In XenoLinux the so called "fast suspend" mode was specifically
added for performance reasons, and it looks like to date pv-ops
only ever supported that mode. So one question is whether
there's going to be any bad performance effect from this.
The other question is that about retaining the use of
stop_machine() then - it seems pretty pointless if you already
bring down all other CPUs.
Jan
next prev parent reply other threads:[~2013-06-20 10:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-19 15:25 [PATCHv4 0/4] xen: maintain an accurate persistent clock in more cases David Vrabel
2013-06-19 15:25 ` [PATCH 1/4] xen: disable non-boot VCPUs during suspend David Vrabel
2013-06-19 17:11 ` Konrad Rzeszutek Wilk
2013-06-20 10:01 ` David Vrabel
2013-06-20 10:38 ` Jan Beulich [this message]
2013-06-20 11:46 ` [Xen-devel] " David Vrabel
2013-06-19 15:25 ` [PATCH 2/4] time: add a notifier chain for when the system time is stepped David Vrabel
2013-06-19 16:52 ` John Stultz
2013-06-19 17:13 ` Konrad Rzeszutek Wilk
2013-06-19 17:38 ` John Stultz
2013-06-20 10:50 ` David Vrabel
2013-06-19 15:25 ` [PATCH 3/4] x86/xen: sync the wallclock " David Vrabel
2013-06-20 10:43 ` [Xen-devel] " Jan Beulich
2013-06-19 15:25 ` [PATCH 4/4] x86/xen: sync the CMOS RTC as well as the Xen wallclock David Vrabel
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