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2022-01-13rtla/osnoise: Add osnoise top modeDaniel Bristot de Oliveira
The rtla osnoise tool is an interface for the osnoise tracer. The osnoise tracer dispatches a kernel thread per-cpu. These threads read the time in a loop while with preemption, softirqs and IRQs enabled, thus allowing all the sources of osnoise during its execution. The osnoise threads take note of the entry and exit point of any source of interferences, increasing a per-cpu interference counter. The osnoise tracer also saves an interference counter for each source of interference. The rtla osnoise top mode displays information about the periodic summary from the osnoise tracer. One example of rtla osnoise top output is: [root@alien ~]# rtla osnoise top -c 0-3 -d 1m -q -r 900000 -P F:1 Operating System Noise duration: 0 00:01:00 | time is in us CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI IRQ Softirq Thread 0 #58 52200000 1031 99.99802 91 60 0 0 52285 0 101 1 #59 53100000 5 99.99999 5 5 0 9 53122 0 18 2 #59 53100000 7 99.99998 7 7 0 8 53115 0 18 3 #59 53100000 8274 99.98441 277 23 0 9 53778 0 660 "rtla osnoise top --help" works and provide information about the available options. Link: https://lkml.kernel.org/r/0d796993abf587ae5a170bb8415c49368d4999e1.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2022-01-13rtla: Add osnoise toolDaniel Bristot de Oliveira
The osnoise tool is the interface for the osnoise tracer. The osnoise tool will have multiple "modes" with different outputs. At this point, no mode is included. The osnoise.c includes the osnoise_context abstraction. It serves to read-save-change-restore the default values from tracing/osnoise/ directory. When the context is deleted, the default values are restored. It also includes some other helper functions for managing osnoise tracer sessions. With these bits and pieces in place, we can start adding some functionality to rtla. Link: https://lkml.kernel.org/r/2d44c21ff561f503b4c7b1813892761818118460.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2022-01-13rtla: Helper functions for rtlaDaniel Bristot de Oliveira
This is a set of utils and tracer helper functions. They are used by rtla mostly to parse config, display data and some trace operations that are not part of libtracefs (because they are only useful it for this case). Link: https://lkml.kernel.org/r/a94c128aba9e6e66d502b7094f2e8c7ac95b12e5.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2022-01-13rtla: Real-Time Linux Analysis toolDaniel Bristot de Oliveira
The rtla is a meta-tool that includes a set of commands that aims to analyze the real-time properties of Linux. But instead of testing Linux as a black box, rtla leverages kernel tracing capabilities to provide precise information about the properties and root causes of unexpected results. rtla --help works and provide information about the available options. This is just the "main" and the Makefile, no function yet. Link: https://lkml.kernel.org/r/bf9118ed43a09e6c054c9a491cbe7411ad1acd89.1639158831.git.bristot@kernel.org Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2021-10-25tools/latency-collector: Use correct size when writing queue_full_warningViktor Rosendahl
queue_full_warning is a pointer, so it is wrong to use sizeof to calculate the number of characters of the string it points to. The effect is that we only print out the first few characters of the warning string. The correct way is to use strlen(). We don't need to add 1 to the strlen() because we don't want to write the terminating null character to stdout. Link: https://lkml.kernel.org/r/20211019160701.15587-1-Viktor.Rosendahl@bmw.de Link: https://lore.kernel.org/r/8fd4bb65ef3da67feac9ce3258cdbe9824752cf1.1629198502.git.jing.yangyang@zte.com.cn Link: https://lore.kernel.org/r/20211012025424.180781-1-davidcomponentone@gmail.com Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Viktor Rosendahl <Viktor.Rosendahl@bmw.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-03-18tools/latency-collector: Remove unneeded semicolonXu Wang
Fix semicolon.cocci warning: tools/tracing/latency/latency-collector.c:1021:2-3: Unneeded semicolon Link: https://lkml.kernel.org/r/20210308022459.59881-1-vulab@iscas.ac.cn Reviewed-by: Viktor Rosendahl <Viktor.Rosendahl@bmw.de> Signed-off-by: Xu Wang <vulab@iscas.ac.cn> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-02-25tracing/tools: fix a couple of spelling mistakesColin Ian King
There is a spelling mistake in the -g help option, I believe it should be "graph". There is also a spelling mistake in a warning message. Fix both mistakes. Link: https://lkml.kernel.org/r/20210225165248.22050-2-Viktor.Rosendahl@bmw.de Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Viktor Rosendahl <Viktor.Rosendahl@bmw.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-02-12tracing/tools: Add the latency-collector to tools directoryViktor Rosendahl
This is a tool that is intended to work around the fact that the preemptoff, irqsoff, and preemptirqsoff tracers only work in overwrite mode. The idea is to act randomly in such a way that we do not systematically lose any latencies, so that if enough testing is done, all latencies will be captured. If the same burst of latencies is repeated, then sooner or later we will have captured all the latencies. It also works with the wakeup_dl, wakeup_rt, and wakeup tracers. However, in that case it is probably not useful to use the random sleep functionality. The reason why it may be desirable to catch all latencies with a long test campaign is that for some organizations, it's necessary to test the kernel in the field and not practical for developers to work iteratively with field testers. Because of cost and project schedules it is not possible to start a new test campaign every time a latency problem has been fixed. It uses inotify to detect changes to /sys/kernel/tracing/trace. When a latency is detected, it will either sleep or print immediately, depending on a function that act as an unfair coin toss. If immediate print is chosen, it means that we open /sys/kernel/tracing/trace and thereby cause a blackout period that will hide any subsequent latencies. If sleep is chosen, it means that we wait before opening /sys/kernel/tracing/trace, by default for 1000 ms, to see if there is another latency during this period. If there is, then we will lose the previous latency. The coin will be tossed again with a different probability, and we will either print the new latency, or possibly a subsequent one. The probability for the unfair coin toss is chosen so that there is equal probability to obtain any of the latencies in a burst. However, this assumes that we make an assumption of how many latencies there can be. By default the program assumes that there are no more than 2 latencies in a burst, the probability of immediate printout will be: 1/2 and 1 Thus, the probability of getting each of the two latencies will be 1/2. If we ever find that there is more than one latency in a series, meaning that we reach the probability of 1, then the table will be expanded to: 1/3, 1/2, and 1 Thus, we assume that there are no more than three latencies and each with a probability of 1/3 of being captured. If the probability of 1 is reached in the new table, that is we see more than two closely occurring latencies, then the table will again be extended, and so on. On my systems, it seems like this scheme works fairly well, as long as the latencies we trace are long enough, 300 us seems to be enough. This userspace program receive the inotify event at the end of a latency, and it has time until the end of the next latency to react, that is to open /sys/kernel/tracing/trace. Thus, if we trace latencies that are >300 us, then we have at least 300 us to react. The minimum latency will of course not be 300 us on all systems, it will depend on the hardware, kernel version, workload and configuration. Example usage: In one shell, give the following command: sudo latency-collector -rvv -t preemptirqsoff -s 2000 -a 3 This will trace latencies > 2000us with the preemptirqsoff tracer, using random sleep with maximum verbosity, with a probability table initialized to a size of 3. In another shell, generate a few bursts of latencies: root@host:~# modprobe preemptirq_delay_test delay=3000 test_mode=alternate burst_size=3 root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger If all goes well, you should be getting stack traces that shows all the different latencies, i.e. you should see all the three functions preemptirqtest_0, preemptirqtest_1, preemptirqtest_2 in the stack traces. Link: https://lkml.kernel.org/r/20210212134421.172750-2-Viktor.Rosendahl@bmw.de Signed-off-by: Viktor Rosendahl <Viktor.Rosendahl@bmw.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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