Re: [PATCH 2/2] perf: SNB exclusive PMU access forINST_RETIRED:PREC_DIST

From: Andi Kleen
Date: Fri Oct 19 2012 - 11:49:51 EST


> + /*
> + * for INST_RETIRED.PREC_DIST to work correctly with PEBS, it must
> + * be measured alone on SNB (exclusive PMU access) as per Intel SDM.
> + */
> + if ((cfg & INTEL_ARCH_EVENT_MASK) == 0x01c0 && !event->attr.exclusive) {
> + pr_info("perf: INST_RETIRED.PREC_DIST only works in exclusive mode\n");
> + return -EINVAL;
> + }


Strictly you have to check for precise too, right?

-Andi
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