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Date:   Wed, 29 Nov 2023 11:51:57 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Adrian Hunter <adrian.hunter@intel.com>
Cc:     Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Thomas Richter <tmricht@linux.ibm.com>,
        Hendrik Brueckner <brueckner@linux.ibm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mike Leach <mike.leach@linaro.org>,
        James Clark <james.clark@arm.com>, coresight@lists.linaro.org,
        linux-arm-kernel@lists.infradead.org,
        Yicong Yang <yangyicong@hisilicon.com>,
        Jonathan Cameron <jonathan.cameron@huawei.com>,
        Will Deacon <will@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org
Subject: Re: [PATCH RFC 1/3] perf/core: Add aux_pause, aux_resume,
 aux_start_paused
Message-ID: <20231129105157.GE30650@noisy.programming.kicks-ass.net>
References: <20231123121851.10826-1-adrian.hunter@intel.com>
 <20231123121851.10826-2-adrian.hunter@intel.com>
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On Thu, Nov 23, 2023 at 02:18:49PM +0200, Adrian Hunter wrote:

> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index 39c6a250dd1b..1232e70adfba 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -456,7 +456,8 @@ struct perf_event_attr {
>  				inherit_thread :  1, /* children only inherit if cloned with CLONE_THREAD */
>  				remove_on_exec :  1, /* event is removed from task on exec */
>  				sigtrap        :  1, /* send synchronous SIGTRAP on event */
> -				__reserved_1   : 26;
> +				aux_start_paused :  1, /* start AUX area tracing paused */
> +				__reserved_1   : 25;
>  
>  	union {
>  		__u32		wakeup_events;	  /* wakeup every n events */
> @@ -507,7 +508,15 @@ struct perf_event_attr {
>  	__u16	sample_max_stack;
>  	__u16	__reserved_2;
>  	__u32	aux_sample_size;
> -	__u32	__reserved_3;
> +
> +	union {
> +		__u32	aux_output_cfg;
> +		struct {
> +			__u64	aux_pause      :  1, /* on overflow, pause AUX area tracing */
> +				aux_resume     :  1, /* on overflow, resume AUX area tracing */
> +				__reserved_3   : 30;
> +		};
> +	};
>  
>  	/*
>  	 * User provided data if sigtrap=1, passed back to user via

So since you're adding a aux_output_cfg word, could you not also put the
start_paused thing in there?