Hello all, Changes in v5: - [PATCH 1/4]: * trace_disable_fsnotify() => latency_fsnotify_disable(), in order to avoid naming conflicts with trace points.
* Using more appropriate operations for the percpu variables. * Moved around the calls to latency_fsnotify_enable/disable() a bit. * Added static branches to reduce overhead when the facility is not in use. * Does not add any trace points anymore. Instead using explicit function calls from sched and idle code. * Unfortunately still adds some gunk to sched and idle code. I do not know how to avoid this. This series is meant to address two issues with the latency tracing. The first three patches provide a method to trace latencies that always occurs very close to each other and to differentiate between them, in spite of the fact that the latency tracers work in overwrite mode. [PATCH 1/4] This implement fs notification for tracing_max_latency. It makes it possible for userspace to detect when a new latency has been detected. [PATCH 2/4] This extends the preemptirq_delay_test module so that it can be used to generate a burst of closely occurring latencies. [PATCH 3/4] This adds a user space program to the tools directory that utilizes the fs notification feature and a randomized algorithm to print out any of the latencies in a burst with approximately equal probability. The last patch is not directly connected but earlier it didn't apply cleanly on its own. However, now it does, so in principle it could be applied separately from the others. [PATCH 4/4] This adds the option console-latency to the trace options. This makes it possible to enable tracing of console latencies. best regards, Viktor Viktor Rosendahl (4): ftrace: Implement fs notification for tracing_max_latency preemptirq_delay_test: Add the burst feature and a sysfs trigger Add the latency-collector to tools ftrace: Add an option for tracing console latencies include/linux/ftrace.h | 31 + include/linux/irqflags.h | 21 + kernel/printk/printk.c | 6 +- kernel/sched/core.c | 3 + kernel/sched/idle.c | 3 + kernel/sched/sched.h | 1 + kernel/trace/Kconfig | 6 +- kernel/trace/preemptirq_delay_test.c | 145 ++- kernel/trace/trace.c | 112 ++- kernel/trace/trace.h | 23 + kernel/trace/trace_hwlat.c | 4 +- kernel/trace/trace_irqsoff.c | 16 + kernel/trace/trace_sched_wakeup.c | 4 + tools/Makefile | 14 +- tools/trace/Makefile | 20 + tools/trace/latency-collector.c | 1211 ++++++++++++++++++++++++++ 16 files changed, 1587 insertions(+), 33 deletions(-) create mode 100644 tools/trace/Makefile create mode 100644 tools/trace/latency-collector.c -- 2.17.1