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From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: Daniel Walker <dwalker@mvista.com>
Cc: linuxppc-dev@ozlabs.org, tglx@linutronix.de, mingo@elte.hu,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver
Date: Fri, 18 May 2007 19:06:04 +0400	[thread overview]
Message-ID: <464DC0DC.7050809@ru.mvista.com> (raw)
In-Reply-To: <1179500217.20519.53.camel@imap.mvista.com>

Daniel Walker wrote:

>>I haven't looked at all the new clock/timer code, is there any  
>>utility in having support for more than one clock source?

> There is if the main clocksource has some issues where it can't be used.

    You mean, having more than one clocksource is *useful* in this case?

> On x86 there are lots of different issues with the clocks, so they have
> to get switches once in a while. For instance, if the TSC changes
> frequencies then it can't be used, or if the TSC stops in different
> power states , it can't be used.. 

    Yeah, and there's the rating systems for both clock sources/events.

> Anything like that on PowerPC?

    Well, the decrementer frequency may change, at least in theory (if the bus 
clock changes).

> Daniel

WBR, Sergei

WARNING: multiple messages have this Message-ID (diff)
From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: Daniel Walker <dwalker@mvista.com>
Cc: Kumar Gala <galak@kernel.crashing.org>,
	tglx@linutronix.de, mingo@elte.hu, linuxppc-dev@ozlabs.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver
Date: Fri, 18 May 2007 19:06:04 +0400	[thread overview]
Message-ID: <464DC0DC.7050809@ru.mvista.com> (raw)
In-Reply-To: <1179500217.20519.53.camel@imap.mvista.com>

Daniel Walker wrote:

>>I haven't looked at all the new clock/timer code, is there any  
>>utility in having support for more than one clock source?

> There is if the main clocksource has some issues where it can't be used.

    You mean, having more than one clocksource is *useful* in this case?

> On x86 there are lots of different issues with the clocks, so they have
> to get switches once in a while. For instance, if the TSC changes
> frequencies then it can't be used, or if the TSC stops in different
> power states , it can't be used.. 

    Yeah, and there's the rating systems for both clock sources/events.

> Anything like that on PowerPC?

    Well, the decrementer frequency may change, at least in theory (if the bus 
clock changes).

> Daniel

WBR, Sergei

  reply	other threads:[~2007-05-18 15:04 UTC|newest]

Thread overview: 105+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-17 17:42 [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver Sergei Shtylyov
2007-05-17 17:47 ` Kumar Gala
2007-05-17 17:47   ` Kumar Gala
2007-05-17 18:07   ` Sergei Shtylyov
2007-05-17 18:07     ` Sergei Shtylyov
2007-05-17 18:17     ` Kumar Gala
2007-05-17 18:17       ` Kumar Gala
2007-05-17 18:26       ` Sergei Shtylyov
2007-05-17 18:26         ` Sergei Shtylyov
2007-05-17 18:31         ` Kumar Gala
2007-05-17 18:31           ` Kumar Gala
2007-05-17 18:42           ` Sergei Shtylyov
2007-05-17 18:42             ` Sergei Shtylyov
2007-05-18 12:39             ` Matt Sealey
2007-05-18 12:39               ` Matt Sealey
2007-05-18 13:45               ` Sergei Shtylyov
2007-05-18 13:45                 ` Sergei Shtylyov
2007-05-18 14:28                 ` Matt Sealey
2007-05-18 14:28                   ` Matt Sealey
2007-05-18 14:48                   ` Thomas Gleixner
2007-05-18 14:48                     ` Thomas Gleixner
2007-05-18 15:37                     ` Matt Sealey
2007-05-18 15:37                       ` Matt Sealey
2007-05-18 16:31                     ` Kumar Gala
2007-05-18 16:31                       ` Kumar Gala
2007-05-18 16:50                       ` Thomas Gleixner
2007-05-18 16:50                         ` Thomas Gleixner
2007-05-18 16:55                         ` Matt Sealey
2007-05-18 16:55                           ` Matt Sealey
2007-05-18 16:52                       ` Matt Sealey
2007-05-18 16:52                         ` Matt Sealey
2007-07-10 10:52                         ` Gabriel Paubert
2007-07-10 10:52                           ` Gabriel Paubert
2007-07-10 14:24                           ` Segher Boessenkool
2007-07-10 14:24                             ` Segher Boessenkool
2007-07-10 23:31                             ` Paul Mackerras
2007-07-10 23:31                               ` Paul Mackerras
2007-07-11  0:10                               ` Segher Boessenkool
2007-07-11  0:10                                 ` Segher Boessenkool
2007-05-18 20:27                       ` David Miller
2007-05-18 20:27                         ` David Miller
2007-05-18 14:56       ` Daniel Walker
2007-05-18 14:56         ` Daniel Walker
2007-05-18 15:06         ` Sergei Shtylyov [this message]
2007-05-18 15:06           ` Sergei Shtylyov
2007-05-18 15:39           ` Daniel Walker
2007-05-18 15:39             ` Daniel Walker
2007-05-18 15:48             ` Sergei Shtylyov
2007-05-18 15:48               ` Sergei Shtylyov
2007-05-19  3:33             ` Paul Mackerras
2007-05-19  3:33               ` Paul Mackerras
2007-05-20  2:43               ` Daniel Walker
2007-05-20  2:43                 ` Daniel Walker
2007-05-20  3:03                 ` Benjamin Herrenschmidt
2007-05-20  3:03                   ` Benjamin Herrenschmidt
2007-05-20 15:03                   ` Matt Sealey
2007-05-20 15:03                     ` Matt Sealey
2007-05-20 21:25                     ` Benjamin Herrenschmidt
2007-05-20 21:25                       ` Benjamin Herrenschmidt
2007-05-20 16:02                   ` Segher Boessenkool
2007-05-20 16:02                     ` Segher Boessenkool
2007-05-20 21:26                     ` Benjamin Herrenschmidt
2007-05-20 21:26                       ` Benjamin Herrenschmidt
2007-05-17 19:27 ` Segher Boessenkool
2007-05-17 19:27   ` Segher Boessenkool
2007-05-17 19:43   ` Sergei Shtylyov
2007-05-17 19:43     ` Sergei Shtylyov
2007-05-17 19:50     ` Segher Boessenkool
2007-05-17 19:50       ` Segher Boessenkool
2007-05-17 20:00       ` Sergei Shtylyov
2007-05-17 20:00         ` Sergei Shtylyov
2007-05-17 20:53         ` Segher Boessenkool
2007-05-17 20:53           ` Segher Boessenkool
2007-05-18  5:04           ` Benjamin Herrenschmidt
2007-05-18  5:04             ` Benjamin Herrenschmidt
2007-05-18  5:39             ` Dave Liu
2007-05-18  5:39               ` Dave Liu
2007-05-18  7:08               ` Benjamin Herrenschmidt
2007-05-18  7:08                 ` Benjamin Herrenschmidt
2007-05-18 13:41                 ` Sergei Shtylyov
2007-05-18 13:41                   ` Sergei Shtylyov
2007-05-18 13:48                   ` Sergei Shtylyov
2007-05-18 23:27                   ` Benjamin Herrenschmidt
2007-05-18 23:27                     ` Benjamin Herrenschmidt
2007-05-18 23:49                     ` Segher Boessenkool
2007-05-18 23:49                       ` Segher Boessenkool
2007-05-19  0:13                       ` Benjamin Herrenschmidt
2007-05-19  0:13                         ` Benjamin Herrenschmidt
2007-05-30 15:56                     ` Milton Miller
2007-05-19  3:34                   ` Paul Mackerras
2007-05-19  3:34                     ` Paul Mackerras
2007-05-24 18:25 ` [PATCH 2.6.21-rt7] PowerPC: fix clockevents for classic CPUs Sergei Shtylyov
2007-05-24 19:10   ` Segher Boessenkool
2007-05-24 19:10     ` Segher Boessenkool
2007-10-18 14:45 ` [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver Sergei Shtylyov
2007-10-18 14:45   ` Sergei Shtylyov
  -- strict thread matches above, loose matches on Subject: below --
2007-05-18  3:24 Albert Cahalan
2007-05-18 14:52 ` Sergei Shtylyov
2007-05-18 14:52   ` Sergei Shtylyov
2007-05-19  1:45   ` Albert Cahalan
2007-05-19  1:45     ` Albert Cahalan
2007-05-19 12:28     ` Segher Boessenkool
2007-05-19 12:28       ` Segher Boessenkool
2007-05-19 18:22       ` Albert Cahalan
2007-05-19 18:22         ` Albert Cahalan

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