30838fcd81
The osnoise tracer is not only a tracer, and a set of tracepoints,
but also a workload dispatcher.
In preparation for having other workloads, e.g., in user-space,
add an option to avoid dispatching the workload.
By not dispatching the workload, the osnoise: tracepoints become
generic events to measure the execution time of *any* task on Linux.
For example:
# cd /sys/kernel/tracing/
# cat osnoise/options
DEFAULTS OSNOISE_WORKLOAD
# echo NO_OSNOISE_WORKLOAD > osnoise/options
# cat osnoise/options
NO_DEFAULTS NO_OSNOISE_WORKLOAD
# echo osnoise > set_event
# echo osnoise > current_tracer
# tail -8 trace
make-94722 [002] d..3. 1371.794507: thread_noise: make:94722 start 1371.794302286 duration 200897 ns
sh-121042 [020] d..3. 1371.794534: thread_noise: sh:121042 start 1371.781610976 duration 8943683 ns
make-121097 [005] d..3. 1371.794542: thread_noise: make:121097 start 1371.794481522 duration 60444 ns
<...>-40 [005] d..3. 1371.794550: thread_noise: migration/5:40 start 1371.794542256 duration 7154 ns
<idle>-0 [018] dNh2. 1371.794554: irq_noise: reschedule:253 start 1371.794553547 duration 40 ns
<idle>-0 [018] dNh2. 1371.794561: irq_noise: local_timer:236 start 1371.794556222 duration 4890 ns
<idle>-0 [018] .Ns2. 1371.794563: softirq_noise: SCHED:7 start 1371.794561803 duration 992 ns
<idle>-0 [018] d..3. 1371.794566: thread_noise: swapper/18:0 start 1371.781368110 duration 13191798 ns
In preparation for the rtla exec_time tracer/tool and
rtla osnoise --user option.
Link: https://lkml.kernel.org/r/f5cfbd37aefd419eefe9243b4d2fc38ed5753fe4.1668692096.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.