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Diffstat (limited to 'kernel/trace/Kconfig')
| -rw-r--r-- | kernel/trace/Kconfig | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 7fa82778c3e6..d567b1717c4c 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -356,6 +356,68 @@ config HWLAT_TRACER file. Every time a latency is greater than tracing_thresh, it will be recorded into the ring buffer. +config OSNOISE_TRACER + bool "OS Noise tracer" + select GENERIC_TRACER + help + 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. The osnoise tracer takes + note of the entry and exit point of any source of interferences, + increasing a per-cpu interference counter. It 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. + + In addition to the tracer, a set of tracepoints were added to + facilitate the identification of the osnoise source. + + The output will appear in the trace and trace_pipe files. + + To enable this tracer, echo in "osnoise" into the current_tracer + file. + +config TIMERLAT_TRACER + bool "Timerlat tracer" + select OSNOISE_TRACER + select GENERIC_TRACER + help + The timerlat tracer aims to help the preemptive kernel developers + to find sources of wakeup latencies of real-time threads. + + The tracer creates a per-cpu kernel thread with real-time priority. + The tracer thread sets a periodic timer to wakeup itself, and goes + to sleep waiting for the timer to fire. At the wakeup, the thread + then computes a wakeup latency value as the difference between + the current time and the absolute time that the timer was set + to expire. + + The tracer prints two lines at every activation. The first is the + timer latency observed at the hardirq context before the + activation of the thread. The second is the timer latency observed + by the thread, which is the same level that cyclictest reports. The + ACTIVATION ID field serves to relate the irq execution to its + respective thread execution. + + The tracer is build on top of osnoise tracer, and the osnoise: + events can be used to trace the source of interference from NMI, + IRQs and other threads. It also enables the capture of the + stacktrace at the IRQ context, which helps to identify the code + path that can cause thread delay. + config MMIOTRACE bool "Memory mapped IO tracing" depends on HAVE_MMIOTRACE_SUPPORT && PCI |