Hello all, Changes in v4:
- [PATCH 1/4]: * Improved support for multiple active trace instances by storing entries that cannot be notified immediately in a linked list instead of a single pointer. With multiple instances this could happen. * Register trace_maxlat_fsnotify_init() with late_initcall_sync(). Previously it was piggy backed on tracer_init_tracefs() and it got called more than once. * Added some comments. - [PATCH 3/4]: * Some of the code was incorrectly added in the next patch. Improved commit message. - [PATCH 4/4]: * Some code from the previous patch was incorrectly included here. 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 doesn't apply cleanly on its own: [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/irqflags.h | 21 + include/trace/events/power.h | 40 + include/trace/events/sched.h | 40 + kernel/printk/printk.c | 6 +- kernel/sched/core.c | 2 + kernel/sched/idle.c | 2 + kernel/trace/Kconfig | 6 +- kernel/trace/preemptirq_delay_test.c | 145 ++- kernel/trace/trace.c | 168 +++- kernel/trace/trace.h | 13 + kernel/trace/trace_hwlat.c | 4 +- kernel/trace/trace_irqsoff.c | 12 + tools/Makefile | 14 +- tools/trace/Makefile | 20 + tools/trace/latency-collector.c | 1211 ++++++++++++++++++++++++++ 15 files changed, 1671 insertions(+), 33 deletions(-) create mode 100644 tools/trace/Makefile create mode 100644 tools/trace/latency-collector.c -- 2.17.1