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From: Zachary Amsden <zamsden@redhat.com>
To: Randy Dunlap <randy.dunlap@oracle.com>
Cc: avi@redhat.com, mtosatti@redhat.com, glommer@redhat.com,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 17/17] Add timekeeping documentation
Date: Wed, 16 Jun 2010 13:59:44 -1000	[thread overview]
Message-ID: <4C196570.5080803@redhat.com> (raw)
In-Reply-To: <20100615132755.9b8d9041.randy.dunlap@oracle.com>

On 06/15/2010 10:27 AM, Randy Dunlap wrote:
> On Mon, 14 Jun 2010 21:34:19 -1000 Zachary Amsden wrote:
>
>    
>> Basic informational document about x86 timekeeping and how KVM
>> is affected.
>>      
> Nice job/information.  Thanks.
>
> Just some typos etc. inline below.
>    

Thanks for all the detailed feedback!  I'll include it all in the next 
revision.  I only have one response:
>
>> + low, the count is halted.  If the output is low when the gate is lowered, the
>> + output automatically goes high (this only affects timer 2).
>> +
>> +Mode 3: Square Wave.   This generates a sine wave.  The count determines the
>>      
> a sine wave is a square wave???
>    

Actually, yes.  The hardware output from timer 2 output goes through a 
low pass filter which effectively smooths the square wave to a sine to 
make the PC speaker sound somewhat less annoying.  I didn't have room to 
depict this in the schematic.  Of course, the counter output isn't 
directly a sine wave, and the LPF may not be all that effective, but it 
was the intent.

Zach

  reply	other threads:[~2010-06-16 23:59 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-15  7:34 TSC cleanups, fixes, documentation for KVM Zachary Amsden
2010-06-15  7:34 ` [PATCH 01/17] Eliminate duplicated timer code Zachary Amsden
2010-06-16 13:07   ` Glauber Costa
2010-06-15  7:34 ` [PATCH 02/17] Make cpu_tsc_khz updates use local CPU Zachary Amsden
2010-06-15  8:02   ` Avi Kivity
2010-06-15  7:34 ` [PATCH 03/17] Unify vendor TSC logic Zachary Amsden
2010-06-16  8:10   ` Jason Wang
2010-06-16 13:22     ` Glauber Costa
2010-06-17  8:03       ` Jason Wang
2010-06-16 18:42     ` Zachary Amsden
2010-06-17  8:15       ` Jason Wang
2010-06-17 20:30         ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 04/17] Fix deep C-state TSC desynchronization Zachary Amsden
2010-06-15  8:09   ` Avi Kivity
2010-06-15  8:14     ` Zachary Amsden
2010-06-16  8:10   ` Jason Wang
2010-06-16 18:43     ` Zachary Amsden
2010-06-16 13:24   ` Glauber Costa
2010-06-16 19:20     ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 05/17] Keep SMP VMs more in sync on unstable TSC Zachary Amsden
2010-06-15  8:11   ` Avi Kivity
2010-06-16  8:11   ` Jason Wang
2010-06-16 13:32   ` Glauber Costa
2010-06-16 21:15     ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 06/17] Rename KVM_REQ_KVMCLOCK_UPDATE Zachary Amsden
2010-06-15  7:34 ` [PATCH 07/17] Perform hardware_enable in CPU_STARTING callback Zachary Amsden
2010-06-15  7:34 ` [PATCH 08/17] Add clock sync request to hardware enable Zachary Amsden
2010-06-15  8:24   ` Avi Kivity
2010-06-15  7:34 ` [PATCH 09/17] Move scale_delta into common header Zachary Amsden
2010-06-15  7:34 ` [PATCH 10/17] Make KVM clock computation work for other scales Zachary Amsden
2010-06-15  7:34 ` [PATCH 11/17] Fix a possible backwards warp of kvmclock Zachary Amsden
2010-06-15  8:40   ` Avi Kivity
2010-06-15 20:37     ` Zachary Amsden
2010-06-15 23:47   ` Marcelo Tosatti
2010-06-16  0:21     ` Zachary Amsden
2010-06-16  0:39       ` Marcelo Tosatti
2010-06-16  8:11   ` Jason Wang
2010-06-16 13:58     ` Glauber Costa
2010-06-16 14:13       ` Avi Kivity
2010-06-16 14:58         ` Glauber Costa
2010-06-16 22:38       ` Zachary Amsden
2010-06-16 19:36     ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 12/17] Add helper function get_kernel_ns Zachary Amsden
2010-06-15  8:41   ` Avi Kivity
2010-06-15 21:03     ` Zachary Amsden
2010-06-15 21:13       ` john stultz
2010-06-16  8:12       ` Jason Wang
2010-06-16 14:03         ` Glauber Costa
2010-06-15  7:34 ` [PATCH 13/17] Add TSC offset tracking Zachary Amsden
2010-06-15  8:44   ` Avi Kivity
2010-06-15  7:34 ` [PATCH 14/17] Fix SVM VMCB reset Zachary Amsden
2010-06-15  7:34 ` [PATCH 15/17] Fix AMD C1 TSC desynchronization Zachary Amsden
2010-06-15  8:47   ` Avi Kivity
2010-06-15  9:21     ` Zachary Amsden
2010-06-15 14:46       ` Roedel, Joerg
2010-06-15  7:34 ` [PATCH 16/17] TSC reset compensation Zachary Amsden
2010-06-15  8:51   ` Avi Kivity
2010-06-15 20:32     ` Zachary Amsden
2010-06-16  0:27   ` Marcelo Tosatti
2010-06-16  0:32     ` Zachary Amsden
2010-06-16 13:52   ` Glauber Costa
2010-06-16 22:36     ` Zachary Amsden
2010-06-15  7:34 ` [PATCH 17/17] Add timekeeping documentation Zachary Amsden
2010-06-15  8:51   ` Avi Kivity
2010-06-15 20:27   ` Randy Dunlap
2010-06-16 23:59     ` Zachary Amsden [this message]
2010-06-17  8:55   ` Andi Kleen
2010-06-17 21:14     ` Zachary Amsden
2010-06-18  7:49       ` Andi Kleen
2010-06-18 16:33         ` Zachary Amsden

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