| Message ID | 0e9d6b25a88b23bfea11e0cb9b95b5b0845b670b.1675181734.git.bristot@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | rtla: Add hwnoise tool | expand |
On Tue, Jan 31, 2023 at 05:30:07PM +0100, Daniel Bristot de Oliveira wrote: > diff --git a/Documentation/tools/rtla/rtla-hwnoise.rst b/Documentation/tools/rtla/rtla-hwnoise.rst > new file mode 100644 > index 000000000000..fb1c52bbc00b > --- /dev/null > +++ b/Documentation/tools/rtla/rtla-hwnoise.rst > @@ -0,0 +1,107 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +============ > +rtla-hwnoise > +============ > +------------------------------------------ > +Detect and quantify hardware-related noise > +------------------------------------------ > + > +:Manual section: 1 > + > +SYNOPSIS > +======== > + > +**rtla hwnoise** [*OPTIONS*] > + > +DESCRIPTION > +=========== > + > +**rtla hwnoise** collects the periodic summary from the *osnoise* tracer > +running with *interrupts disabled*. By disabling interrupts, and the scheduling > +of threads as a consequence, only non-maskable interrupts and hardware-related > +noise is allowed. > + > +The tool also allows the configurations of the *osnoise* tracer and the > +collection of the tracer output. > + > +OPTIONS > +======= > +.. include:: common_osnoise_options.rst > + > +.. include:: common_top_options.rst > + > +.. include:: common_options.rst > + > +EXAMPLE > +======= > +In the example below, the **rtla hwnoise** tool is set to run on CPUs *1-7* > +on a system with 8 cores/16 threads with hyper-threading enabled. > + > +The tool is set to detect any noise higher than *one microsecond*, > +to run for *ten minutes*, displaying a summary of the report at the > +end of the session:: > + > + # rtla hwnoise -c 1-7 -T 1 -d 10m -q > + Hardware-related Noise > + duration: 0 00:10:00 | time is in us > + CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI > + 1 #599 599000000 138 99.99997 3 3 4 74 > + 2 #599 599000000 85 99.99998 3 3 4 75 > + 3 #599 599000000 86 99.99998 4 3 6 75 > + 4 #599 599000000 81 99.99998 4 4 2 75 > + 5 #599 599000000 85 99.99998 2 2 2 75 > + 6 #599 599000000 76 99.99998 2 2 0 75 > + 7 #599 599000000 77 99.99998 3 3 0 75 > + > + > +The first column shows the *CPU*, and the second column shows how many > +*Periods* the tool ran during the session. The *Runtime* is the time > +the tool effectively runs on the CPU. The *Noise* column is the sum of > +all noise that the tool observed, and the *% CPU Aval* is the relation > +between the *Runtime* and *Noise*. > + > +The *Max Noise* column is the maximum hardware noise the tool detected in a > +single period, and the *Max Single* is the maximum single noise seen. > + > +The *HW* and *NMI* columns show the total number of *hardware* and *NMI* noise > +occurrence observed by the tool. > + > +For example, *CPU 3* ran *599* periods of *1 second Runtime*. The CPU received > +*86 us* of noise during the entire execution, leaving *99.99997 %* of CPU time > +for the application. In the worst single period, the CPU caused *4 us* of > +noise to the application, but it was certainly caused by more than one single > +noise, as the *Max Single* noise was of *3 us*. The CPU has *HW noise,* at a > +rate of *six occurrences*/*ten minutes*. The CPU also has *NMIs*, at a higher > +frequency: around *seven per second*. > + > +The tool should report *0* hardware-related noise in the ideal situation. > +For example, by disabling hyper-threading to remove the hardware noise, > +and disabling the TSC watchdog to remove the NMI (it is possible to identify > +this using tracing options of **rtla hwnoise**), it was possible to reach > +the ideal situation in the same hardware:: > + > + # rtla hwnoise -c 1-7 -T 1 -d 10m -q > + Hardware-related Noise > + duration: 0 00:10:00 | time is in us > + CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI > + 1 #599 599000000 0 100.00000 0 0 0 0 > + 2 #599 599000000 0 100.00000 0 0 0 0 > + 3 #599 599000000 0 100.00000 0 0 0 0 > + 4 #599 599000000 0 100.00000 0 0 0 0 > + 5 #599 599000000 0 100.00000 0 0 0 0 > + 6 #599 599000000 0 100.00000 0 0 0 0 > + 7 #599 599000000 0 100.00000 0 0 0 0 > + > +SEE ALSO > +======== > + > +**rtla-osnoise**\(1) > + > +Osnoise tracer documentation: <https://www.kernel.org/doc/html/latest/trace/osnoise-tracer.html> > + > +AUTHOR > +====== > +Written by Daniel Bristot de Oliveira <bristot@kernel.org> > + > +.. include:: common_appendix.rst LGTM, thanks! Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
diff --git a/Documentation/tools/rtla/index.rst b/Documentation/tools/rtla/index.rst index 840f0bf3e803..05d2652e4072 100644 --- a/Documentation/tools/rtla/index.rst +++ b/Documentation/tools/rtla/index.rst @@ -17,6 +17,7 @@ behavior on specific hardware. rtla-timerlat rtla-timerlat-hist rtla-timerlat-top + rtla-hwnoise .. only:: subproject and html diff --git a/Documentation/tools/rtla/rtla-hwnoise.rst b/Documentation/tools/rtla/rtla-hwnoise.rst new file mode 100644 index 000000000000..fb1c52bbc00b --- /dev/null +++ b/Documentation/tools/rtla/rtla-hwnoise.rst @@ -0,0 +1,107 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +rtla-hwnoise +============ +------------------------------------------ +Detect and quantify hardware-related noise +------------------------------------------ + +:Manual section: 1 + +SYNOPSIS +======== + +**rtla hwnoise** [*OPTIONS*] + +DESCRIPTION +=========== + +**rtla hwnoise** collects the periodic summary from the *osnoise* tracer +running with *interrupts disabled*. By disabling interrupts, and the scheduling +of threads as a consequence, only non-maskable interrupts and hardware-related +noise is allowed. + +The tool also allows the configurations of the *osnoise* tracer and the +collection of the tracer output. + +OPTIONS +======= +.. include:: common_osnoise_options.rst + +.. include:: common_top_options.rst + +.. include:: common_options.rst + +EXAMPLE +======= +In the example below, the **rtla hwnoise** tool is set to run on CPUs *1-7* +on a system with 8 cores/16 threads with hyper-threading enabled. + +The tool is set to detect any noise higher than *one microsecond*, +to run for *ten minutes*, displaying a summary of the report at the +end of the session:: + + # rtla hwnoise -c 1-7 -T 1 -d 10m -q + Hardware-related Noise + duration: 0 00:10:00 | time is in us + CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI + 1 #599 599000000 138 99.99997 3 3 4 74 + 2 #599 599000000 85 99.99998 3 3 4 75 + 3 #599 599000000 86 99.99998 4 3 6 75 + 4 #599 599000000 81 99.99998 4 4 2 75 + 5 #599 599000000 85 99.99998 2 2 2 75 + 6 #599 599000000 76 99.99998 2 2 0 75 + 7 #599 599000000 77 99.99998 3 3 0 75 + + +The first column shows the *CPU*, and the second column shows how many +*Periods* the tool ran during the session. The *Runtime* is the time +the tool effectively runs on the CPU. The *Noise* column is the sum of +all noise that the tool observed, and the *% CPU Aval* is the relation +between the *Runtime* and *Noise*. + +The *Max Noise* column is the maximum hardware noise the tool detected in a +single period, and the *Max Single* is the maximum single noise seen. + +The *HW* and *NMI* columns show the total number of *hardware* and *NMI* noise +occurrence observed by the tool. + +For example, *CPU 3* ran *599* periods of *1 second Runtime*. The CPU received +*86 us* of noise during the entire execution, leaving *99.99997 %* of CPU time +for the application. In the worst single period, the CPU caused *4 us* of +noise to the application, but it was certainly caused by more than one single +noise, as the *Max Single* noise was of *3 us*. The CPU has *HW noise,* at a +rate of *six occurrences*/*ten minutes*. The CPU also has *NMIs*, at a higher +frequency: around *seven per second*. + +The tool should report *0* hardware-related noise in the ideal situation. +For example, by disabling hyper-threading to remove the hardware noise, +and disabling the TSC watchdog to remove the NMI (it is possible to identify +this using tracing options of **rtla hwnoise**), it was possible to reach +the ideal situation in the same hardware:: + + # rtla hwnoise -c 1-7 -T 1 -d 10m -q + Hardware-related Noise + duration: 0 00:10:00 | time is in us + CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI + 1 #599 599000000 0 100.00000 0 0 0 0 + 2 #599 599000000 0 100.00000 0 0 0 0 + 3 #599 599000000 0 100.00000 0 0 0 0 + 4 #599 599000000 0 100.00000 0 0 0 0 + 5 #599 599000000 0 100.00000 0 0 0 0 + 6 #599 599000000 0 100.00000 0 0 0 0 + 7 #599 599000000 0 100.00000 0 0 0 0 + +SEE ALSO +======== + +**rtla-osnoise**\(1) + +Osnoise tracer documentation: <https://www.kernel.org/doc/html/latest/trace/osnoise-tracer.html> + +AUTHOR +====== +Written by Daniel Bristot de Oliveira <bristot@kernel.org> + +.. include:: common_appendix.rst
Add a man page for the new rtla hwnoise tool, mostly based in the rtla osnoise top. Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jonathan Corbet <corbet@lwn.net> --- Documentation/tools/rtla/index.rst | 1 + Documentation/tools/rtla/rtla-hwnoise.rst | 107 ++++++++++++++++++++++ 2 files changed, 108 insertions(+) create mode 100644 Documentation/tools/rtla/rtla-hwnoise.rst