linux-kernel - Re: [PATCH -tip] perf, x86: P4 PMU - check for INSTR

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Message-ID: <1282199258.11858.108.camel@minggr.sh.intel.com>
Date:	Thu, 19 Aug 2010 14:27:38 +0800
From:	Lin Ming <ming.m.lin@...el.com>
To:	Cyrill Gorcunov <gorcunov@...nvz.org>
Cc:	Ingo Molnar <mingo@...e.hu>, Stephane Eranian <eranian@...gle.com>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH -tip] perf, x86: P4 PMU - check for INSTR_COMPLETED
 being supported by cpu

On Thu, 2010-08-19 at 14:19 +0800, Cyrill Gorcunov wrote:
> On 8/19/10, Lin Ming <ming.m.lin@...el.com> wrote:
> > On Thu, 2010-08-19 at 02:54 +0800, Cyrill Gorcunov wrote:
> >> INSTR_COMPLETED is supported on particular cpu models of Netburst family,
> >> add a check for that.
> >>
> >> Signed-off-by: Cyrill Gorcunov <gorcunov@...nvz.org>
> >> CC: Lin Ming <ming.m.lin@...el.com>
> >> CC: Stephane Eranian <eranian@...gle.com>
> >> CC: Ingo Molnar <mingo@...e.hu>
> >> CC: Frédéric Weisbecker <fweisbec@...il.com>
> >> CC: Arnaldo Carvalho de Melo <acme@...hat.com>
> >> CC: Peter Zijlstra <peterz@...radead.org>
> >> ---
> >>
> >> Hi Ming, please review this patch, and if you happened to have this
> >> cpu models give it a try please (if you manage to find some spare time
> >> of course). To test it we need RAW event P4_EVENT_INSTR_COMPLETED passed
> >> on any model not mentioned in p4_event_match_cpu_model, and reverse ;)
> >
> > I have model 2 and 6.
> >
> > int main(int argc, char *argv[])
> > {
> >         u64 config = ((((P4_EVENT_INSTR_COMPLETED) << 25)   |
> >                         ((1ULL) << 9)) << 32)                      |
> >                         (0); /* no CCCR needed */
> >
> > 	printf("%llx\n", config);
> > }
> >
> > Use above code to get the raw config value 5a00020000000000.
> >
> > 1. Test on model 2 p4, it falls into the check correctly.
> >
> > # perf top -e r5a00020000000000
> >
> >   Error: perfcounter syscall returned with -1 (Invalid argument)
> >
> >   Fatal: No CONFIG_PERF_EVENTS=y kernel support configured?
> >
> > #dmesg
> > P4 PMU: Unsupported event: INSTR_COMPLETED
> >
> > 2. Test on model 6 p4,
> >
> > PerfTop:       0 irqs/sec  kernel: nan%  exact:  nan% [1000Hz raw
> > 0x5a00020000000000],  (all, 16 CPUs)
> >
> > It has problem, no data is collected.
> >
> > I will check this.
> >
> 
> Thanks Ming, try to set both bogus and bogus bits in event mask

Unfortunately, same result.

Lin Ming

> > Lin Ming
> >
> >>
> >>  arch/x86/kernel/cpu/perf_event_p4.c |   30 ++++++++++++++++++++++++++++++
> >>  1 file changed, 30 insertions(+)
> >>
> >> Index: linux-2.6.git/arch/x86/kernel/cpu/perf_event_p4.c
> >> =====================================================================
> >> --- linux-2.6.git.orig/arch/x86/kernel/cpu/perf_event_p4.c
> >> +++ linux-2.6.git/arch/x86/kernel/cpu/perf_event_p4.c
> >> @@ -350,6 +350,11 @@ static __initconst const u64 p4_hw_cache
> >>   },
> >>  };
> >>
> >> +/*
> >> + * If general events will ever have a reference to the
> >> + * P4_EVENT_INSTR_COMPLETED we would ought to check for
> >> + * cpu model match (see how it's done for RAW events)
> >> + */
> >>  static u64 p4_general_events[PERF_COUNT_HW_MAX] = {
> >>    /* non-halted CPU clocks */
> >>    [PERF_COUNT_HW_CPU_CYCLES] =
> >> @@ -428,6 +433,27 @@ static u64 p4_pmu_event_map(int hw_event
> >>  	return config;
> >>  }
> >>
> >> +/* check cpu model specifics */
> >> +static bool p4_event_match_cpu_model(unsigned int event_idx)
> >> +{
> >> +	/* INSTR_COMPLETED event only exist for model 3, 4, 6 (Prescott) */
> >> +	if (event_idx == P4_EVENT_INSTR_COMPLETED) {
> >> +		if (boot_cpu_data.x86_model	!= 3 &&
> >> +			boot_cpu_data.x86_model	!= 4 &&
> >> +			boot_cpu_data.x86_model	!= 6) {
> >> +			pr_warning("P4 PMU: Unsupported event: INSTR_COMPLETED\n");
> >> +			return false;
> >> +		}
> >> +	}
> >> +
> >> +	/*
> >> +	 * note the IQ_ESCR0, IQ_ESCR1 are available on models 1 and 2
> >> +	 * only but since we don't use them at moment -- no check
> >> +	 */
> >> +
> >> +	return true;
> >> +}
> >> +
> >>  static int p4_validate_raw_event(struct perf_event *event)
> >>  {
> >>  	unsigned int v;
> >> @@ -439,6 +465,10 @@ static int p4_validate_raw_event(struct
> >>  		return -EINVAL;
> >>  	}
> >>
> >> +	/* it may be unsupported */
> >> +	if (!p4_event_match_cpu_model(v))
> >> +		return -EINVAL;
> >> +
> >>  	/*
> >>  	 * it may have some screwed PEBS bits
> >>  	 */
> >
> >
> >


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