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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Glauber Costa <glommer@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	avi@redhat.com, Zachary Amsden <zamsden@redhat.com>
Subject: Re: [PATCH 2/6] Add a global synchronization point for pvclock
Date: Tue, 27 Apr 2010 11:00:35 -0700	[thread overview]
Message-ID: <4BD72643.7050200@goop.org> (raw)
In-Reply-To: <20100427132807.GB18410@amt.cnet>

On 04/27/2010 06:28 AM, Marcelo Tosatti wrote:
>> +	last = atomic64_read(&last_value);
>> +	do {
>> +		if (ret < last)
>> +			return last;
>> +		last = atomic64_cmpxchg(&last_value, last, ret);
>> +	} while (unlikely(last != ret));
>>     
> Wraparound?
>   

If the units nanoseconds, it's good for ~500,000 years of uptime.

    J


  reply	other threads:[~2010-04-27 18:00 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-26 17:46 [PATCH 0/6] pvclock fixes Glauber Costa
2010-04-26 17:46 ` [PATCH 1/6] Enable pvclock flags in vcpu_time_info structure Glauber Costa
2010-04-26 17:46   ` [PATCH 2/6] Add a global synchronization point for pvclock Glauber Costa
2010-04-26 17:46     ` [PATCH 3/6] change msr numbers for kvmclock Glauber Costa
2010-04-26 17:46       ` [PATCH 4/6] export new cpuid KVM_CAP Glauber Costa
2010-04-26 17:46         ` [PATCH 5/6] Try using new kvm clock msrs Glauber Costa
2010-04-26 17:46           ` [PATCH 6/6] don't compute pvclock adjustments if we trust the tsc Glauber Costa
2010-04-27 13:40             ` Marcelo Tosatti
2010-04-27 15:11               ` Glauber Costa
2010-04-27 18:03               ` Avi Kivity
2010-04-27 18:57                 ` Glauber Costa
2010-04-27 13:35           ` [PATCH 5/6] Try using new kvm clock msrs Marcelo Tosatti
2010-04-27 13:30         ` [PATCH 4/6] export new cpuid KVM_CAP Marcelo Tosatti
2010-04-27 15:09           ` Glauber Costa
2010-04-27 16:55           ` Glauber Costa
2010-04-27 18:12         ` Avi Kivity
2010-04-27 19:09           ` Glauber Costa
2010-04-27 19:20             ` Avi Kivity
2010-04-27 13:28     ` [PATCH 2/6] Add a global synchronization point for pvclock Marcelo Tosatti
2010-04-27 18:00       ` Jeremy Fitzhardinge [this message]
2010-04-26 18:11   ` [PATCH 1/6] Enable pvclock flags in vcpu_time_info structure Jeremy Fitzhardinge
2010-04-26 18:45     ` Glauber Costa
2010-04-27 18:07   ` Avi Kivity
2010-04-27 19:09     ` Glauber Costa
2010-04-27  2:21 ` [PATCH 0/6] pvclock fixes Zachary Amsden

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