NAME

perf-daemon - Run record sessions on background

SYNOPSIS

perf daemon
perf daemon [<options>]
perf daemon start  [<options>]
perf daemon stop   [<options>]
perf daemon signal [<options>]
perf daemon ping   [<options>]

DESCRIPTION

This command allows to run simple daemon process that starts and monitors configured record sessions.

You can imagine perf daemon of background process with several perf record child tasks, like:

# ps axjf
...


     1  916507 ... perf daemon start
916507  916508 ...  \_ perf record --control=fifo:control,ack -m 10M -e cycles --overwrite --switch-output -a
916507  916509 ...  \_ perf record --control=fifo:control,ack -m 20M -e sched:* --overwrite --switch-output -a

Not every perf record session is suitable for running under daemon. User need perf session that either produces data on query, like the flight recorder sessions in above example or session that is configured to produce data periodically, like with --switch-output configuration for time and size.

Each session is started with control setup (with perf record --control options).

Sessions are configured through config file, see CONFIG FILE section with EXAMPLES.

OPTIONS

-v, --verbose

--config=<PATH>

--base=<PATH>

All generic options are available also under commands.

START COMMAND

The start command creates the daemon process.

-f, --foreground

STOP COMMAND

The stop command stops all the session and the daemon process.

SIGNAL COMMAND

The signal command sends signal to configured sessions.

--session

PING COMMAND

The ping command sends control ping to configured sessions.

--session

CONFIG FILE

The daemon is configured within standard perf config file by following new variables:

daemon.base: Base path for daemon data. All sessions data are stored under this path.

session-<NAME>.run: Defines new record session. The value is record’s command line without the record keyword.

Each perf record session is run in daemon.base/<NAME> directory.

EXAMPLES

Example with 2 record sessions:

# cat ~/.perfconfig
[daemon]
base=/opt/perfdata

[session-cycles]
run = -m 10M -e cycles --overwrite --switch-output -a

[session-sched]
run = -m 20M -e sched:* --overwrite --switch-output -a

Starting the daemon:

# perf daemon start

Check sessions:

# perf daemon
[603349:daemon] base: /opt/perfdata
[603350:cycles] perf record -m 10M -e cycles --overwrite --switch-output -a
[603351:sched] perf record -m 20M -e sched:* --overwrite --switch-output -a

First line is daemon process info with configured daemon base.

Check sessions with more info:

# perf daemon -v
[603349:daemon] base: /opt/perfdata


  output:  /opt/perfdata/output


  lock:    /opt/perfdata/lock


  up:      1 minutes
[603350:cycles] perf record -m 10M -e cycles --overwrite --switch-output -a


  base:    /opt/perfdata/session-cycles


  output:  /opt/perfdata/session-cycles/output


  control: /opt/perfdata/session-cycles/control


  ack:     /opt/perfdata/session-cycles/ack


  up:      1 minutes
[603351:sched] perf record -m 20M -e sched:* --overwrite --switch-output -a


  base:    /opt/perfdata/session-sched


  output:  /opt/perfdata/session-sched/output


  control: /opt/perfdata/session-sched/control


  ack:     /opt/perfdata/session-sched/ack


  up:      1 minutes

The base path is daemon/session base. The lock file is daemon’s lock file guarding that no other daemon is running on top of the base. The output file is perf record output for specific session. The control and ack files are perf control files. The up number shows minutes daemon/session is running.

Make sure control session is online:

# perf daemon ping
OK   cycles
OK   sched

Send USR2 signal to session cycles to generate perf.data file:

# perf daemon signal --session cycles
signal 12 sent to session 'cycles [603452]'

# tail -2  /opt/perfdata/session-cycles/output
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2020123017013149 ]

Send USR2 signal to all sessions:

# perf daemon signal
signal 12 sent to session 'cycles [603452]'
signal 12 sent to session 'sched [603453]'

# tail -2  /opt/perfdata/session-cycles/output
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2020123017024689 ]
# tail -2  /opt/perfdata/session-sched/output
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2020123017024713 ]

Stop daemon:

# perf daemon stop

SEE ALSO

perf-record(1), perf-config(1)