Re: [PATCH v8 12/13] perf record: implement control commands handling

[Jiri Olsa <jolsa@redhat.com>]

On Wed, Jun 17, 2020 at 11:43:58AM +0300, Alexey Budankov wrote:
> 
> Implement handling of 'enable' and 'disable' control commands
> coming from control file descriptor.
> 
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> ---
>  tools/perf/builtin-record.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index d0b29a1070a0..0394e068dde8 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1527,6 +1527,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  	bool disabled = false, draining = false;
>  	int fd;
>  	float ratio = 0;
> +	enum evlist_ctl_cmd cmd = EVLIST_CTL_CMD_UNSUPPORTED;
>  
>  	atexit(record__sig_exit);
>  	signal(SIGCHLD, sig_handler);
> @@ -1830,6 +1831,21 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  				alarm(rec->switch_output.time);
>  		}
>  
> +		if (evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
> +			switch (cmd) {
> +			case EVLIST_CTL_CMD_ENABLE:
> +				pr_info(EVLIST_ENABLED_MSG);
> +				break;
> +			case EVLIST_CTL_CMD_DISABLE:
> +				pr_info(EVLIST_DISABLED_MSG);
> +				break;
> +			case EVLIST_CTL_CMD_ACK:
> +			case EVLIST_CTL_CMD_UNSUPPORTED:
> +			default:
> +				break;
> +			}
> +		}

so there's still the filter call like:

                        if (evlist__filter_pollfd(rec->evlist, POLLERR | POLLHUP) == 0)
                                draining = true;

it will never be 0 if the control fds are stil alive no?

jirka