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SubjectRe: [PATCH v3 6/9] perf stat: introduce --ctl-fd[-ack] options
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On 20.05.2020 15:38, Jiri Olsa wrote:
> On Wed, May 13, 2020 at 11:03:03AM +0300, Alexey Budankov wrote:
>>
>> Introduce --ctl-fd[-ack] options to pass open file descriptors numbers
>> from command line. Extend perf-stat.txt file with --ctl-fd[-ack] options
>> description. Document possible usage model introduced by --ctl-fd[-ack]
>> options by providing example bash shell script.
>>
>> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
>> ---
>> tools/perf/Documentation/perf-stat.txt | 40 ++++++++++++++++++++++++++
>> tools/perf/builtin-stat.c | 10 +++++++
>> tools/perf/util/stat.h | 2 ++
>> 3 files changed, 52 insertions(+)
>>
>> diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
>> index 3b91b30d7672..7f7a0019fbfc 100644
>> --- a/tools/perf/Documentation/perf-stat.txt
>> +++ b/tools/perf/Documentation/perf-stat.txt
>> @@ -164,6 +164,46 @@ with it. --append may be used here. Examples:
>> 3>results perf stat --log-fd 3 -- $cmd
>> 3>>results perf stat --log-fd 3 --append -- $cmd
>>
>> +--ctl-fd::
>> +--ctl-fd-ack::
>> +
>> +Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,
>> +'disable': disable events). Optionally send control command completion ('ack') to fd-ack
>> +descriptor to synchronize with the controlling process. Example of bash shell script
>> +to enable and disable events during measurements:
>> +
>> +#!/bin/bash
>> +
>> +ctl_dir=/tmp/
>> +
>> +ctl_fifo=${ctl_dir}perf_ctl.fifo
>> +test -p ${ctl_fifo} && unlink ${ctl_fifo}
>> +mkfifo ${ctl_fifo}
>> +exec {ctl_fd}<>${ctl_fifo}
>> +
>> +ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
>> +test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
>> +mkfifo ${ctl_ack_fifo}
>> +exec {ctl_fd_ack}<>${ctl_ack_fifo}
>> +
>> +perf stat -D -1 -e cpu-cycles -a -I 1000 \
>> + --ctl-fd ${ctl_fd} --ctl-fd-ack ${ctl_fd_ack} \
>> + -- sleep 30 &
>> +perf_pid=$!
>> +
>> +sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
>> +sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
>> +
>> +exec {ctl_fd_ack}>&-
>> +unlink ${ctl_ack_fifo}
>> +
>> +exec {ctl_fd}>&-
>> +unlink ${ctl_fifo}
>> +
>> +wait -n ${perf_pid}
>> +exit $?
>> +
>> +
>> --pre::
>> --post::
>> Pre and post measurement hooks, e.g.:
>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>> index abea82a1ba24..88055aaf670f 100644
>> --- a/tools/perf/builtin-stat.c
>> +++ b/tools/perf/builtin-stat.c
>> @@ -187,6 +187,8 @@ static struct perf_stat_config stat_config = {
>> .metric_only_len = METRIC_ONLY_LEN,
>> .walltime_nsecs_stats = &walltime_nsecs_stats,
>> .big_num = true,
>> + .ctl_fd = -1,
>> + .ctl_fd_ack = -1
>> };
>>
>> static inline void diff_timespec(struct timespec *r, struct timespec *a,
>> @@ -984,6 +986,10 @@ static struct option stat_options[] = {
>> "Use with 'percore' event qualifier to show the event "
>> "counts of one hardware thread by sum up total hardware "
>> "threads of same physical core"),
>> + OPT_INTEGER(0, "ctl-fd", &stat_config.ctl_fd,
>> + "Listen on fd descriptor for command to control measurement ('enable': enable events, 'disable': disable events)"),
>> + OPT_INTEGER(0, "ctl-fd-ack", &stat_config.ctl_fd_ack,
>> + "Send control command completion ('ack') to fd ack descriptor"),
>> OPT_END()
>> };
>>
>> @@ -2180,6 +2186,8 @@ int cmd_stat(int argc, const char **argv)
>> signal(SIGALRM, skip_signal);
>> signal(SIGABRT, skip_signal);
>>
>> + evlist__initialize_ctlfd(evsel_list, stat_config.ctl_fd, stat_config.ctl_fd_ack);
>
> please check the return value

Accepted in v4.

~Alexey

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