linux-kernel - Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running perfctrs

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Message-ID: <20100824170936.GH26154@erda.amd.com>
Date:	Tue, 24 Aug 2010 19:09:36 +0200
From:	Robert Richter <robert.richter@....com>
To:	Cyrill Gorcunov <gorcunov@...il.com>
CC:	Ingo Molnar <mingo@...e.hu>, Don Zickus <dzickus@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Lin Ming <ming.m.lin@...el.com>,
	"fweisbec@...il.com" <fweisbec@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Huang, Ying" <ying.huang@...el.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running
 perfctrs

On 24.08.10 12:22:52, Cyrill Gorcunov wrote:
> Btw, guys, I fail to see how new nmi_watchdog work, we have
> default_do_nmi
>   if (!(reason & 0xc0)) {
>     if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == == NOTIFY_STOP)
>       return
>     if (nmi_watchdog_tick(regs, reason))
>       return
> 
> but perf_event_nmi_handler returns NOTIFY_STOP when watchdog is perf event
> and nmi_watchdog_tick _never_ called, or (most probably) I miss something?

The watchdog is disabled during profiling (perf and oprofile) by
calling disable_lapic_nmi_watchdog().

-Robert

-- 
Advanced Micro Devices, Inc.
Operating System Research Center

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