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Date: Sat, 4 Nov 2017 14:26:11 +0100
From: Jiri Olsa <jolsa@redhat.com>
To: Megha Dey <megha.dey@linux.intel.com>
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Subject: Re: [PATCH V0 2/3] perf/x86/intel/bm.c: Add Intel Branch Monitoring
 support
Message-ID: <20171104132611.GE8454@krava>
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On Fri, Nov 03, 2017 at 11:00:05AM -0700, Megha Dey wrote:

SNIP

> +
> +static void intel_bm_event_update(struct perf_event *event)
> +{
> +	union bm_detect_status cur_stat;
> +
> +	rdmsrl(BR_DETECT_STATUS_MSR, cur_stat.raw);
> +	local64_set(&event->hw.prev_count, (uint64_t)cur_stat.raw);
> +}
> +
> +static void intel_bm_event_stop(struct perf_event *event, int mode)
> +{
> +	wrmsrl(BR_DETECT_COUNTER_CONFIG_BASE + event->id,
> +	       (event->hw.bm_counter_conf & ~1));
> +
> +	intel_bm_event_update(event);
> +}
> +
> +static void intel_bm_event_del(struct perf_event *event, int flags)
> +{
> +	intel_bm_event_stop(event, flags);
> +}
> +
> +static void intel_bm_event_read(struct perf_event *event)
> +{
> +}

should you call intel_bm_event_update in here? so the read syscall
gets updated data in case the case the event is active

jirka