From: David Vrabel <david.vrabel@citrix.com>
To: Jan Beulich <JBeulich@suse.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 12:46:47 +0100 [thread overview]
Message-ID: <51C2EBA7.9060208@citrix.com> (raw)
In-Reply-To: <51C2F7C102000078000DF504@nat28.tlf.novell.com>
On 20/06/13 11:38, Jan Beulich wrote:
>>>> 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.
Yes :(
On a VM with 4 VCPUs, disable_boot_cpus() took > 200 ms.
I'll have to rethink this.
David
next prev parent reply other threads:[~2013-06-20 11:46 UTC|newest]
Thread overview: 27+ 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 10:01 ` David Vrabel
2013-06-19 17:11 ` Konrad Rzeszutek Wilk
2013-06-20 10:38 ` [Xen-devel] " Jan Beulich
2013-06-20 11:46 ` David Vrabel [this message]
2013-06-20 11:46 ` David Vrabel
2013-06-20 10:38 ` Jan Beulich
2013-06-19 15:25 ` 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 17:13 ` Konrad Rzeszutek Wilk
2013-06-19 17:38 ` John Stultz
2013-06-19 17:38 ` John Stultz
2013-06-20 10:50 ` David Vrabel
2013-06-20 10:50 ` David Vrabel
2013-06-19 16:52 ` John Stultz
2013-06-19 15:25 ` 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
2013-06-20 10:43 ` Jan Beulich
2013-06-19 15:25 ` David Vrabel
2013-06-19 15:25 ` [PATCH 4/4] x86/xen: sync the CMOS RTC as well as the Xen wallclock David Vrabel
2013-06-19 15:25 ` David Vrabel
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