linux-kernel - Re: [PATCH V7 5/5] perf tools: adding sink configuration for cs

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Date:   Wed, 31 Aug 2016 08:14:22 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Suzuki K Poulose <Suzuki.Poulose@....com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...radead.org>,
        Peter Zijlstra <peterz@...radead.org>, jolsa@...nel.org,
        Ingo Molnar <mingo@...hat.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH V7 5/5] perf tools: adding sink configuration for cs_etm PMU

On 31 August 2016 at 03:37, Suzuki K Poulose <Suzuki.Poulose@....com> wrote:
> On 30/08/16 17:19, Mathieu Poirier wrote:
>>
>> Using the PMU::set_drv_config() callback to enable the CoreSight
>> sink that will be used for the trace session.
>
>
>> +int cs_etm_set_drv_config(struct perf_evsel_config_term *term)
>> +{
>> +       int ret;
>> +       char enable_sink[ENABLE_SINK_MAX];
>> +
>> +       snprintf(enable_sink, ENABLE_SINK_MAX, "%s/%s",
>> +                term->val.drv_cfg, "enable_sink");
>> +
>> +       ret = cs_device__print_file(enable_sink, "%d", 1);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       return 0;
>> +}
>
>
>
> Don't we have to disable the sink at the end of the session ? How is that
> taken care of ? Did I miss that ?
>

Correct - the sink has to be disabled once it is no longer needed.  It
is a little tricky to do and I haven't decided on the best way to
proceed.  Fortunately that aspect doesn't affect this patchset.

Mathieu

> Suzuki