-
--no-filter
-
Do not filter out the trace-cmd threads. By default, the threads are
filtered out to not be traced by events. This option will have the trace-cmd
threads also be traced.
-
-R trigger
-
Specify a trigger for the previous event. This must come after a -e.
This will add a given trigger to the given event. To only enable the trigger
and not the event itself, then place the event after the -v option.
See Documentation/trace/events.txt in the Linux kernel source for more
information on triggers.
-
-v
-
This will cause all events specified after it on the command line to not
be traced. This is useful for selecting a subsystem to be traced but to
leave out various events. For Example: "-e sched -v -e "*stat\*"" will
enable all events in the sched subsystem except those that have "stat" in
their names.
Note: the *-v* option was taken from the way grep(1) inverts the following
matches.
-
-F
-
This will filter only the executable that is given on the command line. If
no command is given, then it will filter itself (pretty pointless).
Using -F will let you trace only events that are caused by the given
command.
-
-P pid
-
Similar to -F but lets you specify a process ID to trace.
-
-c
-
Used with either -F (or -P if kernel supports it) to trace the process'
children too.
-
--user
-
Execute the specified command as given user.
-
-C clock
-
Set the trace clock to "clock".
Use trace-cmd(1) list -C to see what clocks are available.
-
-o output-file
-
By default, trace-cmd report will create a trace.dat file. You can
specify a different file to write to with the -o option.
-
-l function-name
-
This will limit the function and function_graph tracers to only trace
the given function name. More than one -l may be specified on the
command line to trace more than one function. This supports both full
regex(3) parsing, or basic glob parsing. If the filter has only alphanumeric,
_, *, ? and . characters, then it will be parsed as a basic glob.
to force it to be a regex, prefix the filter with ^ or append it with $
and it will then be parsed as a regex.
-
-g function-name
-
This option is for the function_graph plugin. It will graph the given
function. That is, it will only trace the function and all functions that
it calls. You can have more than one -g on the command line.
-
-n function-name
-
This has the opposite effect of -l. The function given with the -n
option will not be traced. This takes precedence, that is, if you include
the same function for both -n and -l, it will not be traced.
-
-d
-
Some tracer plugins enable the function tracer by default. Like the
latency tracers. This option prevents the function tracer from being
enabled at start up.
-
-D
-
The option -d will try to use the function-trace option to disable the
function tracer (if available), otherwise it defaults to the proc file:
/proc/sys/kernel/ftrace_enabled, but will not touch it if the function-trace
option is available. The -D option will disable both the ftrace_enabled
proc file as well as the function-trace option if it exists.
Note, this disable function tracing for all users, which includes users
outside of ftrace tracers (stack_tracer, perf, etc).
-
-O option
-
Ftrace has various options that can be enabled or disabled. This allows
you to set them. Appending the text no to an option disables it.
For example: "-O nograph-time" will disable the "graph-time" Ftrace
option.
-
-s interval
-
The processes that trace-cmd creates to record from the ring buffer need
to wake up to do the recording. Setting the interval to zero will cause
the processes to wakeup every time new data is written into the buffer.
But since Ftrace is recording kernel activity, the act of this processes
going back to sleep may cause new events into the ring buffer which will
wake the process back up. This will needlessly add extra data into the
ring buffer.
The 'interval' metric is microseconds. The default is set to 1000 (1 ms).
This is the time each recording process will sleep before waking up to
record any new data that was written to the ring buffer.
-
-r priority
-
The priority to run the capture threads at. In a busy system the trace
capturing threads may be staved and events can be lost. This increases
the priority of those threads to the real time (FIFO) priority.
But use this option with care, it can also change the behaviour of
the system being traced.
-
-b size
-
This sets the ring buffer size to size kilobytes. Because the Ftrace
ring buffer is per CPU, this size is the size of each per CPU ring buffer
inside the kernel. Using "-b 10000" on a machine with 4 CPUs will make
Ftrace have a total buffer size of 40 Megs.
-
-B buffer-name
-
If the kernel supports multiple buffers, this will add a buffer with
the given name. If the buffer name already exists, that buffer is just
reset and will not be deleted at the end of record execution. If the
buffer is created, it will be removed at the end of execution (unless
the -k is set, or start command was used).
After a buffer name is stated, all events added after that will be
associated with that buffer. If no buffer is specified, or an event
is specified before a buffer name, it will be associated with the
main (toplevel) buffer.
trace-cmd record -e sched -B block -e block -B time -e timer sleep 1
The above is will enable all sched events in the main buffer. It will
then create a 'block' buffer instance and enable all block events within
that buffer. A 'time' buffer instance is created and all timer events
will be enabled for that event.
-
-m size
-
The max size in kilobytes that a per cpu buffer should be. Note, due
to rounding to page size, the number may not be totally correct.
Also, this is performed by switching between two buffers that are half
the given size thus the output may not be of the given size even if
much more was written.
Use this to prevent running out of diskspace for long runs.
-
-M cpumask
-
Set the cpumask for to trace. It only affects the last buffer instance
given. If supplied before any buffer instance, then it affects the
main buffer. The value supplied must be a hex number.
trace-cmd record -p function -M c -B events13 -e all -M 5
If the -M is left out, then the mask stays the same. To enable all
CPUs, pass in a value of '-1'.
-
-k
-
By default, when trace-cmd is finished tracing, it will reset the buffers
and disable all the tracing that it enabled. This option keeps trace-cmd
from disabling the tracer and reseting the buffer. This option is useful for
debugging trace-cmd.
Note: usually trace-cmd will set the "tracing_on" file back to what it
was before it was called. This option will leave that file set to zero.
-
-i
-
By default, if an event is listed that trace-cmd does not find, it
will exit with an error. This option will just ignore events that are
listed on the command line but are not found on the system.
-
-N host:port
-
If another machine is running "trace-cmd listen", this option is used to
have the data sent to that machine with UDP packets. Instead of writing
to an output file, the data is sent off to a remote box. This is ideal for
embedded machines with little storage, or having a single machine that
will keep all the data in a single repository.
Note: This option is not supported with latency tracer plugins:
wakeup, wakeup_rt, irqsoff, preemptoff and preemptirqsoff
-
-V cid:port
-
If recording on a guest VM and the host is running trace-cmd listen with
the -V option as well, or if this is recording on the host, and a guest
in running trace-cmd listen with the -V option, then connect to the
listener (the same as connecting with the -N option via the network).
This has the same limitations as the -N option above with respect to
latency tracer plugins.
-
-t
-
This option is used with -N, when there’s a need to send the live data
with TCP packets instead of UDP. Although TCP is not nearly as fast as
sending the UDP packets, but it may be needed if the network is not that
reliable, the amount of data is not that intensive, and a guarantee is
needed that all traced information is transfered successfully.
-
-q | --quiet
-
For use with recording an application. Suppresses normal output
(except for errors) to allow only the application’s output to be displayed.
-
--date
-
With the --date option, "trace-cmd" will write timestamps into the
trace buffer after it has finished recording. It will then map the
timestamp to gettimeofday which will allow wall time output from the
timestamps reading the created trace.dat file.
-
--max-graph-depth depth
-
Set the maximum depth the function_graph tracer will trace into a function.
A value of one will only show where userspace enters the kernel but not any
functions called in the kernel. The default is zero, which means no limit.
-
--cmdlines-size size
-
Set the number of entries the kernel tracing file "saved_cmdlines" can
contain. This file is a circular buffer which stores the mapping between
cmdlines and PIDs. If full, it leads to unresolved cmdlines ("<…>") within
the trace. The kernel default value is 128.
-
--module module
-
Filter a module’s name in function tracing. It is equivalent to adding
:mod:module after all other functions being filtered. If no other function
filter is listed, then all modules functions will be filtered in the filter.
'--module snd' is equivalent to '-l :mod:snd'
'--module snd -l "*jack*"' is equivalent to '-l "*jack*:mod:snd"'
'--module snd -n "*"' is equivalent to '-n :mod:snd'
-
--proc-map
-
Save the traced process address map into the trace.dat file. The traced
processes can be specified using the option -P, or as a given command.
-
--profile
-
With the --profile option, "trace-cmd" will enable tracing that can
be used with trace-cmd-report(1) --profile option. If a tracer -p is
not set, and function graph depth is supported by the kernel, then
the function_graph tracer will be enabled with a depth of one (only
show where userspace enters into the kernel). It will also enable
various tracepoints with stack tracing such that the report can show
where tasks have been blocked for the longest time.
See trace-cmd-profile(1) for more details and examples.
-
-G
-
Set interrupt (soft and hard) events as global (associated to CPU
instead of tasks). Only works for --profile.
-
-H event-hooks
-
Add custom event matching to connect any two events together. When not
used with --profile, it will save the parameter and this will be
used by trace-cmd report --profile, too. That is:
trace-cmd record -H hrtimer_expire_entry,hrtimer/hrtimer_expire_exit,hrtimer,sp
trace-cmd report --profile
Will profile hrtimer_expire_entry and hrtimer_expire_ext times.
See trace-cmd-profile(1) for format.
-
-S
-
(for --profile only)
Only enable the tracer or events speficied on the command line.
With this option, the function_graph tracer is not enabled, nor are
any events (like sched_switch), unless they are specifically specified
on the command line (i.e. -p function -e sched_switch -e sched_wakeup)
-
--temp directory
-
When trace-cmd is recording the trace, it records the per CPU data into
a separate file for each CPU. At the end of the trace, these files are
concatenated onto the final trace.dat file. If the final file is on a network
file system, it may not be appropriate to copy these temp files into the
same location. --temp can be used to tell trace-cmd where those temp
files should be created.
-
--ts-offset offset
-
Add an offset for the timestamp in the trace.dat file. This will add a
offset option into the trace.dat file such that a trace-cmd report will
offset all the timestamps of the events by the given offset. The offset
is in raw units. That is, if the event timestamps are in nanoseconds
the offset will also be in nanoseconds even if the displayed units are
in microseconds.
-
--tsync-interval
-
Set the loop interval, in ms, for timestamps synchronization with guests:
If a negative number is specified, timestamps synchronization is disabled
If 0 is specified, no loop is performed - timestamps offset is calculated only twice,"
at the beginning and at the end of the trace.
Timestamps synchronization with guests works only if there is support for VSOCK.\n"
-
--tsc2nsec
-
Convert the current clock to nanoseconds, using tsc multiplier and shift from the Linux
kernel’s perf interface. This option does not change the trace clock, just assumes that
the tsc multiplier and shift are applicable for the selected clock. You may use the
"-C tsc2nsec" clock, if not sure what clock to select.
-
--stderr
-
Have output go to stderr instead of stdout, but the output of the command
executed will not be changed. This is useful if you want to monitor the
output of the command being executed, but not see the output from trace-cmd.
-
--poll
-
Waiting for data to be available on the trace ring-buffers may trigger
IPIs. This might generate unacceptable trace noise when tracing low latency
or real time systems. The poll option forces trace-cmd to use O_NONBLOCK.
Traces are extracted by busy waiting, which will hog the CPUs, so only use
when really needed.
-
--name
-
Give a specific name for the current agent being processed. Used after -A to
give the guest being traced a name. Useful when using the vsocket ID instead of
a name of the guest.
-
--verbose[=level]
-
Set the log level. Supported log levels are "none", "critical", "error", "warning",
"info", "debug", "all" or their identifiers "0", "1", "2", "3", "4", "5", "6". Setting the log
level to specific value enables all logs from that and all previous levels.
The level will default to "info" if one is not specified.
Example: enable all critical, error and warning logs
trace-cmd record --verbose=warning
-
--file-version
-
Desired version of the output file. Supported versions are 6 or 7.
-
--compression
-
Compression of the trace output file, one of these strings can be passed:
'any' - auto select the best available compression algorithm
'none' - do not compress the trace file
'name' - the name of the desired compression algorithms. Available algorithms can be listed with
trace-cmd list -c
-
--proxy vsocket
-
Use a vsocket proxy to reach the agent. Acts the same as -A (for an
agent) but will send the proxy connection to the agent. It is expected to
run on a privileged guest that the host is aware of (as denoted by the
cid in the -P option for the agent).