Messages in this thread | | | Date | Fri, 19 Oct 2012 17:58:09 +0200 | Subject | Re: [PATCH 2/2] perf: SNB exclusive PMU access for INST_RETIRED:PREC_DIST | From | Stephane Eranian <> |
| |
On Fri, Oct 19, 2012 at 5:49 PM, Andi Kleen <ak@linux.intel.com> wrote: >> + /* >> + * 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? > Yes, the restriction is enforced only when PEBS is active and this is what I do based on where pebs_aliases() is called.
> -Andi
| |