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Tomas Glozar
c1bb78002a
Add an appendix documenting how to unset options in RTLA. For options where unsetting is currently not supported, add a note into the respective section. An additional note is added for --on-threshold trace. As it is considered distinct from --trace, it is not reverted by --no-trace. Reviewed-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260629083654.1548925-4-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
64 lines
2.0 KiB
Plaintext
64 lines
2.0 KiB
Plaintext
.. SPDX-License-Identifier: GPL-2.0
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UNSETTING OPTIONS
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=================
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The effect of most command line options can be reverted by prepending "no-" to
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the long variant of the option, for example:
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$ rtla timerlat top -p 100 --no-period
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resets the period back to the default value of 1000 us.
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If a command line option sets multiple RTLA parameters at once, the inverted
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option will revert all of them, even if they were not set by the particular
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option. For example, since using "--auto" implies "--trace", specifying
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"--trace --no-auto" will also disable trace output, just like if "--no-trace"
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was specified.
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SIGINT BEHAVIOR
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===============
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On the first SIGINT, RTLA exits after collecting all outstanding samples up to
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the point of receiving the signal.
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When receiving more than one SIGINT, RTLA discards any outstanding samples, and
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exits while displaying only samples that have already been processed.
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If SIGINT is received during RTLA cleanup, RTLA exits immediately via
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the default signal handler.
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Note: For the purpose of SIGINT behavior, the expiry of duration specified via
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the -d/--duration option is treated as equivalent to receiving a SIGINT. For
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example, a SIGINT received after duration expired but samples have not been
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processed yet will drop any outstanding samples.
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Also note that when using the timerlat tool in BPF mode, samples are processed
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in-kernel; RTLA only copies them out to display them to the user. A second
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SIGINT does not affect in-kernel sample aggregation.
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EXIT STATUS
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===========
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::
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0 Passed: the test did not hit the stop tracing condition
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1 Error: invalid argument
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2 Failed: the test hit the stop tracing condition
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129 Help: either user requested help or incorrect option was specified
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REPORTING BUGS
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==============
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Report bugs to <linux-kernel@vger.kernel.org>
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and <linux-trace-devel@vger.kernel.org>
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LICENSE
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=======
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**rtla** is Free Software licensed under the GNU GPLv2
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COPYING
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=======
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Copyright \(C) 2021 Red Hat, Inc. Free use of this software is granted under
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the terms of the GNU Public License (GPL).
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