Re: [PATCH] perf, x86: Add hw_watchdog_set_attr() in a sake ofnmi-watchdog on P4

From: Cyrill Gorcunov
Date: Tue Jun 28 2011 - 12:16:49 EST


On Tue, Jun 28, 2011 at 05:53:31PM +0200, Stephane Eranian wrote:
> Cyrill,
>
> #ifdef CONFIG_HARDLOCKUP_DETECTOR
> +void __weak hw_nmi_watchdog_set_attr(struct perf_event_attr *wd_attr) { }
>
> The weak function has to remain inside the #ifdef. Remember it's just an
> override in case you cannot using the generic cycle event. It is only needed
> when you have the HARDLOCK detector, i.e., are using the PMU to detect
> deadlocks.
>
> I suspect P4 may be the only one so far which exhibited a problem there.
>

heh ;) Guys, maybe we're talking about different things? Don, when you said
"Though I do wonder about this call in the watchdog" you meant the

wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
--> hw_nmi_watchdog_set_attr(wd_attr);

itself? Ie you suspect some different point where to call it?

When I said not a "best place" I meant about __weak function bare implementation
placed that near to call (which is looked somehow suspicious for me from overall
code structure), but I didn't mean the call sequence itself ;)

Cyrill
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