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Subject: Re: [PATCH v7 03/13] perf evlist: implement control command handling
 functions
To:     Jiri Olsa <jolsa@redhat.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
References: <5de4b954-24f0-1e8d-5a0d-7b12783b8218@linux.intel.com>
 <88988ce1-52d3-21e7-f0dc-bac5fde63cb2@linux.intel.com>
 <20200623145450.GF2619137@krava>
From:   Alexey Budankov <alexey.budankov@linux.intel.com>
Organization: Intel Corp.
Message-ID: <83328e86-36af-091f-8729-f4ba3d30a3f1@linux.intel.com>
Date:   Wed, 24 Jun 2020 14:48:20 +0300
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On 23.06.2020 17:54, Jiri Olsa wrote:
> On Wed, Jun 03, 2020 at 06:54:47PM +0300, Alexey Budankov wrote:
> 
> SNIP
> 
>> +			case EVLIST_CTL_CMD_ACK:
>> +			case EVLIST_CTL_CMD_UNSUPPORTED:
>> +			default:
>> +				pr_debug("ctlfd: unsupported %d\n", *cmd);
>> +				break;
>> +			}
>> +			if (!(*cmd == EVLIST_CTL_CMD_ACK || *cmd == EVLIST_CTL_CMD_UNSUPPORTED))
>> +				evlist__ctlfd_ack(evlist);
>> +		}
>> +	}
>> +
>> +	if (stat_entries[ctlfd_pos].revents & (POLLHUP | POLLERR))
>> +		evlist__finalize_ctlfd(evlist);
>> +	else
>> +		stat_entries[ctlfd_pos].revents = 0;
>> +
>> +	return err;
>> +}
>> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
>> index 0d8b361f1c8e..bccf0a970371 100644
>> --- a/tools/perf/util/evlist.h
>> +++ b/tools/perf/util/evlist.h
>> @@ -360,4 +360,21 @@ void perf_evlist__force_leader(struct evlist *evlist);
>>  struct evsel *perf_evlist__reset_weak_group(struct evlist *evlist,
>>  						 struct evsel *evsel,
>>  						bool close);
>> +#define EVLIST_CTL_CMD_ENABLE_TAG  "enable"
>> +#define EVLIST_CTL_CMD_DISABLE_TAG "disable"
>> +#define EVLIST_CTL_CMD_ACK_TAG     "ack\n"
> 
> why the \n at the end of ack?

This \n stops reading by read command from within shell script.
\n can be avoided in ack if using "read -n 3 -u $fd res" instead
of just "read -u $fd res" by the script.

~Alexey

> 
> jirka
>