kernel/linux.git/include/linux/trace.h, branch v6.6.132

tracing: Mark binary printing functions with __printf() attribute

2025-06-04T12:41:54+00:00

[ Upstream commit 196a062641fe68d9bfe0ad36b6cd7628c99ad22c ] Binary printing functions are using printf() type of format, and compiler is not happy about them as is: kernel/trace/trace.c:3292:9: error: function ‘trace_vbprintk’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format] kernel/trace/trace_seq.c:182:9: error: function ‘trace_seq_bprintf’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format] Fix the compilation errors by adding __printf() attribute. While at it, move existing __printf() attributes from the implementations to the declarations. IT also fixes incorrect attribute parameters that are used for trace_array_printk(). Signed-off-by: Andy Shevchenko Reviewed-by: Kees Cook Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20250321144822.324050-4-andriy.shevchenko@linux.intel.com Signed-off-by: Petr Mladek Signed-off-by: Sasha Levin

tracing: Allow creating instances with specified system events

2025-04-10T12:37:41+00:00

[ Upstream commit d23569979ca1cd139a42c410e0c7b9e6014c3b3a ] A trace instance may only need to enable specific events. As the eventfs directory of an instance currently creates all events which adds overhead, allow internal instances to be created with just the events in systems that they care about. This currently only deals with systems and not individual events, but this should bring down the overhead of creating instances for specific use cases quite bit. The trace_array_get_by_name() now has another parameter "systems". This parameter is a const string pointer of a comma/space separated list of event systems that should be created by the trace_array. (Note if the trace_array already exists, this parameter is ignored). The list of systems is saved and if a module is loaded, its events will not be added unless the system for those events also match the systems string. Link: https://lore.kernel.org/linux-trace-kernel/20231213093701.03fddec0@gandalf.local.home Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Sean Paul Cc: Arun Easi Cc: Daniel Wagner Tested-by: Dmytro Maluka Signed-off-by: Steven Rostedt (Google) Stable-dep-of: 0b4ffbe4888a ("tracing: Correct the refcount if the hist/hist_debug file fails to open") Signed-off-by: Sasha Levin

tracing: Add trace_array_puts() to write into instance

2023-02-07T17:49:56+00:00

Add a generic trace_array_puts() that can be used to "trace_puts()" into an allocated trace_array instance. This is just another variant of trace_array_printk(). Link: https://lkml.kernel.org/r/20230207173026.584717290@goodmis.org Cc: Masami Hiramatsu Cc: Andrew Morton Reviewed-by: Ross Zwisler Signed-off-by: Steven Rostedt (Google)

tracing: Fix warning on variable 'struct trace_array'

2022-11-17T02:52:05+00:00

Move the declaration of 'struct trace_array' out of #ifdef CONFIG_TRACING block, to fix the following warning when CONFIG_TRACING is not set: >> include/linux/trace.h:63:45: warning: 'struct trace_array' declared inside parameter list will not be visible outside of this definition or declaration Link: https://lkml.kernel.org/r/20221107160556.2139463-1-shraash@google.com Fixes: 1a77dd1c2bb5 ("scsi: tracing: Fix compile error in trace_array calls when TRACING is disabled") Cc: "Martin K. Petersen" Cc: Arun Easi Acked-by: Masami Hiramatsu (Google) Reviewed-by: Guenter Roeck Signed-off-by: Aashish Sharma Signed-off-by: Steven Rostedt (Google)

scsi: tracing: Fix compile error in trace_array calls when TRACING is disabled

2022-09-25T16:39:52+00:00

Fix this compilation error seen when CONFIG_TRACING is not enabled: drivers/scsi/qla2xxx/qla_os.c: In function 'qla_trace_init': drivers/scsi/qla2xxx/qla_os.c:2854:25: error: implicit declaration of function 'trace_array_get_by_name'; did you mean 'trace_array_set_clr_event'? [-Werror=implicit-function-declaration] 2854 | qla_trc_array = trace_array_get_by_name("qla2xxx"); | ^~~~~~~~~~~~~~~~~~~~~~~ | trace_array_set_clr_event drivers/scsi/qla2xxx/qla_os.c: In function 'qla_trace_uninit': drivers/scsi/qla2xxx/qla_os.c:2869:9: error: implicit declaration of function 'trace_array_put' [-Werror=implicit-function-declaration] 2869 | trace_array_put(qla_trc_array); | ^~~~~~~~~~~~~~~ Link: https://lore.kernel.org/r/20220907233308.4153-2-aeasi@marvell.com Reported-by: kernel test robot Reviewed-by: Steven Rostedt (Google) Signed-off-by: Arun Easi Signed-off-by: Martin K. Petersen

trace/osnoise: Fix 'no previous prototype' warnings

2021-06-28T18:12:26+00:00

kernel test robot reported some osnoise functions with "no previous prototype." Fix these warnings by making local functions static, and by adding: void osnoise_trace_irq_entry(int id); void osnoise_trace_irq_exit(int id, const char *desc); to include/linux/trace.h. Link: https://lkml.kernel.org/r/e40d3cb4be8bde921f4b40fa6a095cf85ab807bd.1624872608.git.bristot@redhat.com Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Reported-by: kernel test robot Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (VMware)

trace: Add osnoise tracer

2021-06-25T23:57:01+00:00

In the context of high-performance computing (HPC), the Operating System Noise (*osnoise*) refers to the interference experienced by an application due to activities inside the operating system. In the context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread can cause noise to the system. Moreover, hardware-related jobs can also cause noise, for example, via SMIs. The osnoise tracer leverages the hwlat_detector by running a similar loop with preemption, SoftIRQs and IRQs enabled, thus allowing all the sources of *osnoise* during its execution. Using the same approach of hwlat, osnoise takes 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 interference counter for NMI, IRQs, SoftIRQs, and threads is increased anytime the tool observes these interferences' entry events. When a noise happens without any interference from the operating system level, the hardware noise counter increases, pointing to a hardware-related noise. In this way, osnoise can account for any source of interference. At the end of the period, the osnoise tracer prints the sum of all noise, the max single noise, the percentage of CPU available for the thread, and the counters for the noise sources. Usage Write the ASCII text "osnoise" into the current_tracer file of the tracing system (generally mounted at /sys/kernel/tracing). For example:: [root@f32 ~]# cd /sys/kernel/tracing/ [root@f32 tracing]# echo osnoise > current_tracer It is possible to follow the trace by reading the trace trace file:: [root@f32 tracing]# cat trace # tracer: osnoise # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth MAX # || / SINGLE Interference counters: # |||| RUNTIME NOISE % OF CPU NOISE +-----------------------------+ # TASK-PID CPU# |||| TIMESTAMP IN US IN US AVAILABLE IN US HW NMI IRQ SIRQ THREAD # | | | |||| | | | | | | | | | | <...>-859 [000] .... 81.637220: 1000000 190 99.98100 9 18 0 1007 18 1 <...>-860 [001] .... 81.638154: 1000000 656 99.93440 74 23 0 1006 16 3 <...>-861 [002] .... 81.638193: 1000000 5675 99.43250 202 6 0 1013 25 21 <...>-862 [003] .... 81.638242: 1000000 125 99.98750 45 1 0 1011 23 0 <...>-863 [004] .... 81.638260: 1000000 1721 99.82790 168 7 0 1002 49 41 <...>-864 [005] .... 81.638286: 1000000 263 99.97370 57 6 0 1006 26 2 <...>-865 [006] .... 81.638302: 1000000 109 99.98910 21 3 0 1006 18 1 <...>-866 [007] .... 81.638326: 1000000 7816 99.21840 107 8 0 1016 39 19 In addition to the regular trace fields (from TASK-PID to TIMESTAMP), the tracer prints a message at the end of each period for each CPU that is running an osnoise/CPU thread. The osnoise specific fields report: - The RUNTIME IN USE reports the amount of time in microseconds that the osnoise thread kept looping reading the time. - The NOISE IN US reports the sum of noise in microseconds observed by the osnoise tracer during the associated runtime. - The % OF CPU AVAILABLE reports the percentage of CPU available for the osnoise thread during the runtime window. - The MAX SINGLE NOISE IN US reports the maximum single noise observed during the runtime window. - The Interference counters display how many each of the respective interference happened during the runtime window. Note that the example above shows a high number of HW noise samples. The reason being is that this sample was taken on a virtual machine, and the host interference is detected as a hardware interference. Tracer options The tracer has a set of options inside the osnoise directory, they are: - osnoise/cpus: CPUs at which a osnoise thread will execute. - osnoise/period_us: the period of the osnoise thread. - osnoise/runtime_us: how long an osnoise thread will look for noise. - osnoise/stop_tracing_us: stop the system tracing if a single noise higher than the configured value happens. Writing 0 disables this option. - osnoise/stop_tracing_total_us: stop the system tracing if total noise higher than the configured value happens. Writing 0 disables this option. - tracing_threshold: the minimum delta between two time() reads to be considered as noise, in us. When set to 0, the default value will be used, which is currently 5 us. Additional Tracing In addition to the tracer, a set of tracepoints were added to facilitate the identification of the osnoise source. - osnoise:sample_threshold: printed anytime a noise is higher than the configurable tolerance_ns. - osnoise:nmi_noise: noise from NMI, including the duration. - osnoise:irq_noise: noise from an IRQ, including the duration. - osnoise:softirq_noise: noise from a SoftIRQ, including the duration. - osnoise:thread_noise: noise from a thread, including the duration. Note that all the values are *net values*. For example, if while osnoise is running, another thread preempts the osnoise thread, it will start a thread_noise duration at the start. Then, an IRQ takes place, preempting the thread_noise, starting a irq_noise. When the IRQ ends its execution, it will compute its duration, and this duration will be subtracted from the thread_noise, in such a way as to avoid the double accounting of the IRQ execution. This logic is valid for all sources of noise. Here is one example of the usage of these tracepoints:: osnoise/8-961 [008] d.h. 5789.857532: irq_noise: local_timer:236 start 5789.857529929 duration 1845 ns osnoise/8-961 [008] dNh. 5789.858408: irq_noise: local_timer:236 start 5789.858404871 duration 2848 ns migration/8-54 [008] d... 5789.858413: thread_noise: migration/8:54 start 5789.858409300 duration 3068 ns osnoise/8-961 [008] .... 5789.858413: sample_threshold: start 5789.858404555 duration 8723 ns interferences 2 In this example, a noise sample of 8 microseconds was reported in the last line, pointing to two interferences. Looking backward in the trace, the two previous entries were about the migration thread running after a timer IRQ execution. The first event is not part of the noise because it took place one millisecond before. It is worth noticing that the sum of the duration reported in the tracepoints is smaller than eight us reported in the sample_threshold. The reason roots in the overhead of the entry and exit code that happens before and after any interference execution. This justifies the dual approach: measuring thread and tracing. Link: https://lkml.kernel.org/r/e649467042d60e7b62714c9c6751a56299d15119.1624372313.git.bristot@redhat.com Cc: Phil Auld Cc: Sebastian Andrzej Siewior Cc: Kate Carcia Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Alexandre Chartre Cc: Clark Willaims Cc: John Kacur Cc: Juri Lelli Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira [ Made the following functions static: trace_irqentry_callback() trace_irqexit_callback() trace_intel_irqentry_callback() trace_intel_irqexit_callback() Added to include/trace.h: osnoise_arch_register() osnoise_arch_unregister() Fixed define logic for LATENCY_FS_NOTIFY Reported-by: kernel test robot ] Signed-off-by: Steven Rostedt (VMware)

tracing: Add printf attribute to log function

2021-02-02T22:02:05+00:00

Attributing the function allows the compiler to more thoroughly check the use of the function with -Wformat and similar flags. Link: https://lkml.kernel.org/r/20201221162715.3757291-1-trix@redhat.com Signed-off-by: Tom Rix Signed-off-by: Steven Rostedt (VMware)

tracing: Add trace_export support for trace_marker

2020-10-05T10:43:53+00:00

Add the support to route trace_marker buffer to other destination via trace_export. Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Alexander Shishkin Signed-off-by: Tingwei Zhang Signed-off-by: Alexander Shishkin Link: https://lore.kernel.org/r/20201005071319.78508-5-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman

tracing: Add trace_export support for event trace

2020-10-05T10:43:53+00:00

Only function traces can be exported to other destinations currently. This patch exports event trace as well. Move trace export related function to the beginning of file so other trace can call trace_process_export() to export. Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Alexander Shishkin Signed-off-by: Tingwei Zhang Signed-off-by: Alexander Shishkin Link: https://lore.kernel.org/r/20201005071319.78508-4-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman