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From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	Robert Richter <robert.richter@amd.com>,
	Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] oprofile: re-arm APIC_DM_NMI in ppro_check_ctrs()
Date: Mon, 10 Nov 2008 19:31:35 +0300	[thread overview]
Message-ID: <20081110163135.GD16522@localhost> (raw)
In-Reply-To: <49185F08.9030705@cosmosbay.com>

[Eric Dumazet - Mon, Nov 10, 2008 at 05:19:20PM +0100]
...
>>
>> Hi Eric,
>>
>> for the record
>>
>> 	apic_write(APIC_LVTPC, APIC_DM_NMI);
>>
>> is not just 'unmask' but also *zeroify* (not sure if I wrote this
>> word right :) all fields when the origianl code was just 'unmasking'
>> TPC register
>>
>> 	apic_write(APIC_LVTPC, apic_read(APIC_LVTPC) & ~APIC_LVT_MASKED);
>>
>> that is why apic_read() was in former.
>>
>
> Well, given that APIC_LVTPC is initialized by oprofile init to value APIC_DM_NMI,
> I avoid an apic_read() and just write APIC_DM_NMI again...
>
> Presumably, apic_read(APIC_LVTPC) should return APIC_DM_NMI or APIC_DM_NMI|APIC_LVT_MASKED
>
> Thanks
>

Yes, just grepped the sources -- it seems nobody else touching
this register indeed.
		- Cyrill -

  reply	other threads:[~2008-11-10 16:31 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-07 17:13 [git pull] OProfile fixes for v2.6.28 Robert Richter
2008-11-07 18:22 ` Ingo Molnar
2008-11-10  8:05 ` Eric Dumazet
2008-11-10  8:43   ` Andi Kleen
2008-11-10  9:01     ` Eric Dumazet
2008-11-10 14:23     ` [PATCH] oprofile: re-arm APIC_DM_NMI in ppro_check_ctrs() Eric Dumazet
2008-11-10 15:49       ` Andi Kleen
2008-11-10 15:50         ` Eric Dumazet
2008-11-10 17:46           ` Andi Kleen
2008-11-11  8:32         ` Eric Dumazet
2008-11-17 17:33           ` Robert Richter
2008-11-17 18:25             ` Andi Kleen
2008-11-18  8:57               ` Robert Richter
2008-11-10 16:11       ` Cyrill Gorcunov
2008-11-10 16:19         ` Eric Dumazet
2008-11-10 16:31           ` Cyrill Gorcunov [this message]
2008-11-17 17:57   ` [git pull] OProfile fixes for v2.6.28 Robert Richter

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