rtla-timerlat¶
Measures the operating system timer latency¶
- Manual section:
1
SYNOPSIS¶
rtla timerlat [MODE] ...
DESCRIPTION¶
The rtla timerlat tool is an interface for the timerlat tracer. The timerlat tracer dispatches a kernel thread per-cpu. These threads set a periodic timer to wake themselves up and go back to sleep. After the wakeup, they collect and generate useful information for the debugging of operating system timer latency.
The timerlat tracer outputs information in two ways. It periodically prints the timer latency at the timer IRQ handler and the Thread handler. It also enables the trace of the most relevant information via osnoise: tracepoints.
The rtla timerlat tool sets the options of the timerlat tracer and collects and displays a summary of the results. By default, the collection is done synchronously in kernel space using a dedicated BPF program attached to the timerlat tracer. If either BPF or the osnoise:timerlat_sample tracepoint it attaches to is unavailable, the rtla timerlat tool falls back to using tracefs to process the data asynchronously in user space.
The rtla timerlat top mode displays a summary of the periodic output from the timerlat tracer. The rtla timerlat hist mode displays a histogram of each tracer event occurrence. For further details, please refer to the respective man page.
MODES¶
top
Prints the summary from timerlat tracer.
hist
Prints a histogram of timerlat samples.
If no MODE is given, the top mode is called, passing the arguments.
OPTIONS¶
-h, --help
Display the help text.
For other options, see the man page for the corresponding mode.
SEE ALSO¶
rtla-timerlat-top(1), rtla-timerlat-hist(1)
timerlat tracer documentation: <https://www.kernel.org/doc/html/latest/trace/timerlat-tracer.html>
REPORTING BUGS¶
Report bugs to <linux-kernel@vger.kernel.org> and <linux-trace-devel@vger.kernel.org>
LICENSE¶
rtla is Free Software licensed under the GNU GPLv2
COPYING¶
Copyright (C) 2021 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).