Messages in this thread |  | | | Subject | Re: [RFC] perf_events: support for uncore a.k.a. nest units | | From | Peter Zijlstra <> | | Date | Thu, 21 Jan 2010 09:59:04 +0100 |
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On Thu, 2010-01-21 at 09:47 +0100, stephane eranian wrote: > I don't think that is correct. You can be using the uncore PMU on Nehalem > without any core PMU event. The only thing to realize is that uncore PMU > shares the same interrupt vector as core PMU. You need to configure which > core the uncore is going to interrupt on. This is done via a bitmask, so you > can interrupt more than one core at a time. Several strategies are possible.
Ah, sharing the IRQ line is no problem. But from reading I got the impression you need to configure an Offcore counter. See 30.6.2.1:
• EN_PMI_COREn (bit n, n = 0, 3 if four cores are present): When set, processor core n is programmed to receive an interrupt signal from any interrupt enabled uncore counter. PMI delivery due to an uncore counter overflow is enabled by setting IA32_DEBUG_CTL.Offcore_PMI_EN to 1.
Which seems to indicate a link with the off-core response thing.
However I would be very glad to be wrong :-)
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