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SubjectRe: [PATCH] ARC: perf: ARC 700 PMU doesn't support sampling events
On Wed, Nov 13, 2013 at 04:06:06PM +0100, Mischa Jonker wrote:
> The ARC 700 does not have an interrupt associated with it, and as
> such it cannot trigger when a counter overflows. As the counters are
> 48 bit, it will usually take at least 100 days before a counter
> overflows, so for mere counting of events, there is no problem.
> Sampling is not supported though.

Acked-by: Peter Zijlstra <peterz@infradead.org>

> Cc: Vineet Gupta <vgupta@synopsys.com>
> Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
> ---
> arch/arc/kernel/perf_event.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
> index 759e5f3..e46d81f 100644
> --- a/arch/arc/kernel/perf_event.c
> +++ b/arch/arc/kernel/perf_event.c
> @@ -99,6 +99,10 @@ static int arc_pmu_event_init(struct perf_event *event)
> struct hw_perf_event *hwc = &event->hw;
> int ret;
>
> + /* ARC 700 PMU does not support sampling events */
> + if (is_sampling_event(event))
> + return -ENOENT;
> +
> switch (event->attr.type) {
> case PERF_TYPE_HARDWARE:
> if (event->attr.config >= PERF_COUNT_HW_MAX)
> --
> 1.7.9.5
>


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