Changes in v3: - renamed functions and types from perf_evlist_ to evlist_ to avoid clash with libperf code; - supported commands to be strings of variable length consisting of command name and also possibly including command specific data; - merged docs update with the code changes; - updated docs for -D,--delay=-1 option for stat and record modes;
v2: https://lore.kernel.org/lkml/d582cc3d-2302-c7e2-70d3-bc7ab6f62...@linux.intel.com/ Changes in v2: - renamed resume and pause commands to enable and disable ones, renamed CTL_CMD_RESUME and CTL_CMD_PAUSE to CTL_CMD_ENABLE and CTL_CMD_DISABLE to fit to the appropriate ioctls and avoid mixing up with PAUSE_OUTPUT ioctl; - factored out event handling loop into a handle_events() for stat mode; - separated -D,--delay=-1 into separate patches for stat and record modes; v1: https://lore.kernel.org/lkml/825a5132-b58d-c0b6-b050-5a6040386...@linux.intel.com/ repo: tip of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git perf/core The patch set implements handling of 'start disabled', 'enable' and 'disable' external control commands which can be provided for stat and record modes of the tool from an external controlling process. 'start disabled' command can be used to postpone enabling of events in the beginning of a monitoring session. 'enable' and 'disable' commands can be used to enable and disable events correspondingly any time after the start of the session. The 'start disabled', 'enable' and 'disable' external control commands can be used to focus measurement on specially selected time intervals of workload execution. Focused measurement reduces tool intrusion and influence on workload behavior, reduces distortion and amount of collected and stored data, mitigates data accuracy loss because measurement and data capturing happen only during intervals of interest. A controlling process can be a bash shell script [1], native executable or any other language program that can directly work with file descriptors, e.g. pipes [2], and spawn a process, specially the tool one. -D,--delay <val> option is extended with -1 value to skip events enabling in the beginning of a monitoring session ('start disabled' command). --ctl-fd and --ctl-fd-ack command line options are introduced to provide the tool with a pair of file descriptors to listen to control commands and reply to the controlling process on the completion of received commands. The tool reads control command message from ctl-fd descriptor, handles the command and optionally replies acknowledgement message to fd-ack descriptor, if it is specified on the command line. 'enable' command is recognized as 'enable' string message and 'disable' command is recognized as 'disable' string message both received from ctl-fd descriptor. Completion message is 'ack\n' and sent to fd-ack descriptor. example bash script demonstrating simple use case: #!/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 ${ctl_fd_ack} \ -- sleep 40 & perf_pid=$! 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})" sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e2 && echo "enabled(${e2})" sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d2 && echo "disabled(${d2})" exec {ctl_fd_ack}>&- && unlink ${ctl_ack_fifo} exec {ctl_fd}>&- && unlink ${ctl_fifo} wait -n ${perf_pid} exit $? Script output: [root@host acme] example Events disabled # time counts unit events 1.001101062 <not counted> cpu-cycles 2.002994944 <not counted> cpu-cycles 3.004864340 <not counted> cpu-cycles 4.006727177 <not counted> cpu-cycles Events enabled enabled(ack) 4.993808464 3,124,246 cpu-cycles 5.008597004 3,325,624 cpu-cycles 6.010387483 83,472,992 cpu-cycles 7.012266598 55,877,621 cpu-cycles 8.014175695 97,892,729 cpu-cycles 9.016056093 68,461,242 cpu-cycles 10.017937507 55,449,643 cpu-cycles 11.019830154 68,938,167 cpu-cycles 12.021719952 55,164,101 cpu-cycles 13.023627550 70,535,720 cpu-cycles 14.025580995 53,240,125 cpu-cycles disabled(ack) 14.997518260 53,558,068 cpu-cycles Events disabled 15.027216416 <not counted> cpu-cycles 16.029052729 <not counted> cpu-cycles 17.030904762 <not counted> cpu-cycles 18.032073424 <not counted> cpu-cycles 19.033805074 <not counted> cpu-cycles Events enabled enabled(ack) 20.001279097 3,021,022 cpu-cycles 20.035044381 6,434,367 cpu-cycles 21.036923813 89,358,251 cpu-cycles 22.038825169 72,516,351 cpu-cycles # time counts unit events 23.040715596 55,046,157 cpu-cycles 24.042643757 78,128,649 cpu-cycles 25.044558535 61,052,428 cpu-cycles 26.046452785 62,142,806 cpu-cycles 27.048353021 74,477,971 cpu-cycles 28.050241286 61,001,623 cpu-cycles 29.052149961 61,653,502 cpu-cycles disabled(ack) 30.004980264 82,729,640 cpu-cycles Events disabled 30.053516176 <not counted> cpu-cycles 31.055348366 <not counted> cpu-cycles 32.057202097 <not counted> cpu-cycles 33.059040702 <not counted> cpu-cycles 34.060843288 <not counted> cpu-cycles 35.000888624 <not counted> cpu-cycles [root@host acme]# [1] http://man7.org/linux/man-pages/man1/bash.1.html [2] http://man7.org/linux/man-pages/man2/pipe.2.html --- Alexey Budankov (9): perf evlist: introduce control file descriptors perf evlist: implement control command handling functions perf stat: factor out event handling loop into a function perf stat: extend -D,--delay option with -1 value perf stat: implement control commands handling perf stat: introduce --ctl-fd[-ack] options perf record: extend -D,--delay option with -1 value perf record: implement control commands handling perf record: introduce --ctl-fd[-ack] options tools/perf/Documentation/perf-record.txt | 44 +++++++- tools/perf/Documentation/perf-stat.txt | 45 +++++++- tools/perf/builtin-record.c | 39 ++++++- tools/perf/builtin-stat.c | 137 ++++++++++++++++------- tools/perf/builtin-trace.c | 2 +- tools/perf/util/evlist.c | 131 ++++++++++++++++++++++ tools/perf/util/evlist.h | 24 ++++ tools/perf/util/record.h | 4 +- tools/perf/util/stat.h | 4 +- 9 files changed, 379 insertions(+), 51 deletions(-) -- 2.24.1
