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From: "David S. Ahern" <daahern@cisco.com>
To: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Anthony Liguori <anthony@codemonkey.ws>,
	kvm@vger.kernel.org, glommer@redhat.com, zamsden@redhat.com,
	avi@redhat.com, mtosatti@redhat.com
Subject: Re: [RFC 0/4] KVM in-kernel PM Timer implementation
Date: Tue, 14 Dec 2010 11:00:59 -0700	[thread overview]
Message-ID: <4D07B0DB.7010701@cisco.com> (raw)
In-Reply-To: <4D078D5A.9060804@codemonkey.ws>



On 12/14/10 08:29, Anthony Liguori wrote:

>> I recently used to investigate the performance benefit. In a Linux
>> guest, I was running a program that calls gettimeofday() 'n' times
>> in a loop (the PM Timer register is read during each call). With
>> in-kernel PM Timer, I observed a significant reduction of program
>> execution time.
>>    
> 
> I've played with this in the past.  Can you post real numbers,
> preferably, with a real work load?

2 years ago I posted relative comparisons of the time sources for older
RHEL guests:
http://www.mail-archive.com/kvm@vger.kernel.org/msg07231.html

What's the relative speed of the in-kernel pmtimer compared to the PIT?

David

  reply	other threads:[~2010-12-14 18:01 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <344060531.680691292328457867.JavaMail.root@zmail07.collab.prod.int.phx2.redhat.com>
2010-12-14 12:09 ` [RFC 0/4] KVM in-kernel PM Timer implementation Ulrich Obergfell
2010-12-14 13:34   ` Avi Kivity
2010-12-14 13:40     ` Glauber Costa
2010-12-14 13:49       ` Avi Kivity
2010-12-14 13:52         ` Gleb Natapov
2010-12-14 15:32         ` Anthony Liguori
2010-12-14 15:38           ` Avi Kivity
2010-12-14 16:04             ` Anthony Liguori
2010-12-15  9:33               ` Avi Kivity
2010-12-14 15:29   ` Anthony Liguori
2010-12-14 18:00     ` David S. Ahern [this message]
2010-12-14 19:49       ` Anthony Liguori
2010-12-14 19:54         ` David S. Ahern
2010-12-14 21:46           ` Anthony Liguori
2010-12-14 23:59             ` David S. Ahern
     [not found] <953393305.700721292337871455.JavaMail.root@zmail07.collab.prod.int.phx2.redhat.com>
2010-12-14 14:44 ` Ulrich Obergfell
2010-12-14 15:12   ` Avi Kivity
     [not found] <1956121317.795411292413874075.JavaMail.root@zmail07.collab.prod.int.phx2.redhat.com>
2010-12-15 11:53 ` Ulrich Obergfell
2012-02-21 18:10   ` Peter Lieven

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