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From: Richard Henderson <rth7680@gmail.com>
To: john stultz <johnstul@us.ibm.com>
Cc: ink@jurassic.park.msu.ru, lkml <linux-kernel@vger.kernel.org>,
	linux-alpha@vger.kernel.org
Subject: Re: [PATCH] Convert alpha to use arch_gettimeoffset()
Date: Tue, 16 Jun 2009 10:45:16 -0700	[thread overview]
Message-ID: <4A37DA2C.8020106@gmail.com> (raw)
In-Reply-To: <1244832112.7231.3.camel@localhost.localdomain>

john stultz wrote:
> On Fri, 2009-06-12 at 00:03 -0700, Richard Henderson wrote:
>   
>> john stultz wrote:
>>     
>>> I suspect the alpha arch could even be further improved to provide and
>>> rpcc() based clocksource, but not having the hardware, I don't feel
>>> comfortable attempting the more complicated conversion (but I'd be glad
>>> to help if anyone else is interested).
>>>       
>> Unfortunately this isn't possible.  The rpcc value is only 32-bits wide,
>> and so rolls over in approx 3 to 4 seconds.  Thus all the contortions to
>> try and use the truncated value for sub 1 second adjustments.
>>     
>
> That's actually ok. The ACPI PM clocksource on x86 is only 24 bits wide
> and wraps every 5 seconds. The generic timekeeping code handles the
> wrapping and accumulation for you.
>   
Interesting.
> Might you create a patch that does this conversion and apply it on top
> of mine? 
Unfortunately I don't have working hardware anymore.  Perhaps Ivan will 
be able to help here.


r~

  reply	other threads:[~2009-06-16 17:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-11 22:10 [PATCH] Convert alpha to use arch_gettimeoffset() john stultz
2009-06-11 22:21 ` Dialup Jon Norstog
2009-06-11 22:52 ` [PATCH] Convert m32r " john stultz
2009-06-12  7:03 ` [PATCH] Convert alpha " Richard Henderson
2009-06-12 18:41   ` john stultz
2009-06-16 17:45     ` Richard Henderson [this message]
2009-06-17 15:29       ` Ivan Kokshaysky
2009-07-17  0:09 ` [RESEND][PATCH] Convert m32r " john stultz
2009-07-17  0:17 ` [PATCH] Convert cris " john stultz
2009-07-17  0:20 ` [PATCH] Convert m68k " john stultz
2009-07-17  0:20   ` john stultz
2009-07-17  0:25 ` [PATCH] Convert blackfin " john stultz
2009-07-17  2:26   ` Mike Frysinger
2009-07-17  5:17     ` john stultz
2009-07-17  5:33     ` john stultz
2009-07-20  8:24       ` Mike Frysinger

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