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From: Mike Travis <travis@sgi.com>
To: Pavel Machek <pavel@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	rpurdie@rpsys.net, Jack Steiner <steiner@sgi.com>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 1/1] SGI X86 UV: Provide a System Activity Indicator	driver
Date: Thu, 02 Oct 2008 07:33:44 -0700	[thread overview]
Message-ID: <48E4DBC8.3070202@sgi.com> (raw)
In-Reply-To: <20081002083700.GB19993@atrey.karlin.mff.cuni.cz>

Pavel Machek wrote:
>> Pavel Machek wrote:
>>>> Another relevant point is that I will be adding a bit more functionality
>>>> to disable the timer interrupt on truly "idle" cpus (like have been idle
>>>> for some amount of seconds).  We would then use the "exit from idle"
>>>> callback to reestablish the timer interrupt.  [This would allow them to
>>>> enter power down states if appropriate.]
>>> Should you look at nohz instead of reinventing it? 
>> Thanks, I did look at it.  Quite complex.  Maybe I'm missing something
>> but I don't see how it fits in?  Are you saying I should be using
> 
> I seen your remark above about disabling timer interrupt on idle
> cpus. That's exactly nohz functionality, right? Maybe I misunderstood
> you and you meant "my monitoring interrupt" and not "generic system
> timer interrupt"?
> 
> 									Pavel

Ahh, yes, now I see... ;-)

And thanks for the pointer, I hadn't looked at this before.

In regards to "powering down" a UV system, it's not clear yet that it will
help much unless we can power down a whole lot more of the system than just
the cpus... ;-)  [but in reality, reducing power use any time you can is 
real necessity.]

Btw, are you ok with the remainder of the patch?

Thanks,
Mike

  reply	other threads:[~2008-10-02 14:33 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-19 14:37 [PATCH 0/1] " Mike Travis
2008-09-19 14:37 ` [PATCH 1/1] " Mike Travis
2008-09-22 11:48   ` Ingo Molnar
2008-09-22 14:42     ` Mike Travis
2008-09-28 19:42       ` Pavel Machek
2008-10-01 18:15         ` Mike Travis
2008-10-01 19:41           ` Mike Travis
2008-10-02  8:37           ` Pavel Machek
2008-10-02 14:33             ` Mike Travis [this message]
2008-09-22 14:47     ` Mike Travis
2008-10-24 11:19 Mike Travis
2008-10-24 12:01 ` Pavel Machek
2008-10-24 12:05   ` Ingo Molnar
2008-10-24 12:27     ` Mike Travis
2008-10-24 18:12       ` Andi Kleen
2008-10-24 22:18         ` Mike Travis
2008-10-24 22:24           ` Mike Travis
2008-10-27 11:42             ` Ingo Molnar
2008-10-27 14:38               ` Mike Travis
2008-10-25  6:56           ` Andi Kleen
2008-10-27 15:12             ` Mike Travis
2008-10-27 11:36           ` Ingo Molnar
2008-10-27 11:43       ` Ingo Molnar
2008-10-24 12:14   ` Mike Travis

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