The behavior of RTLA on receiving SIGINT is currently undocumented. Describe it in RTLA's common appendix that appears in man pages for all RTLA tools to avoid confusion.
Suggested-by: Attila Fazekas <[email protected]> Signed-off-by: Tomas Glozar <[email protected]> --- Note: There was a bug in SIGINT behavior, fixed in upcoming commit [1]. [1] https://lore.kernel.org/linux-trace-kernel/[email protected]/ Documentation/tools/rtla/common_appendix.txt | 21 ++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/Documentation/tools/rtla/common_appendix.txt b/Documentation/tools/rtla/common_appendix.txt index 53cae7537537..8c90a02588e7 100644 --- a/Documentation/tools/rtla/common_appendix.txt +++ b/Documentation/tools/rtla/common_appendix.txt @@ -1,5 +1,26 @@ .. SPDX-License-Identifier: GPL-2.0 +SIGINT BEHAVIOR +=============== + +On the first SIGINT, RTLA exits after collecting all outstanding samples up to +the point of receiving the signal. + +When receiving more than one SIGINT, RTLA discards any outstanding samples, and +exits while displaying only samples that have already been processed. + +If SIGINT is received during RTLA cleanup, RTLA exits immediately via +the default signal handler. + +Note: For the purpose of SIGINT behavior, the expiry of duration specified via +the -d/--duration option is treated as equivalent to receiving a SIGINT. For +example, a SIGINT received after duration expired but samples have not been +processed yet will drop any outstanding samples. + +Also note that when using the timerlat tool in BPF mode, samples are processed +in-kernel; RTLA only copies them out to display them to the user. A second +SIGINT does not affect in-kernel sample aggregation. + EXIT STATUS =========== -- 2.53.0
