Hi, Thank you Steven and Daniel for reviewing v1 and providing suggestions. These set of patches [v3] capture latency events caused by interrupts and premption disabled in kernel. The patches are based on the hist trigger feature developed by Tom Zanussi.
v2: https://lkml.org/lkml/2016/8/24/296 Mount Debugfs mount -t debugfs nodev /sys/kernel/debug Examples of triggers: echo 'hist:key=latency.log2:val=hitcount:sort=latency' > /sys/kernel/debug/tracing/events/latency/latency_preempt/trigger echo 'hist:key=cpu,latency:val=hitcount:sort=latency if cpu==1' > /sys/kernel/debug/tracing/events/latency/latency_preempt/trigger echo 'hist:key=ltype,cpu:val=latency:sort=ltype,cpu if ltype==0' > /sys/kernel/debug/tracing/events/latency/latency_preempt/trigger Histogram output: cat /sys/kernel/debug/tracing/events/latency/latency_preempt/hist Changes from v2 as per comments from Daniel - Use single tracepoint for irq/preempt/critical timings by introducing a trace type field to differentiate trace type in the same tracepoint. The suspicious RCU usage error was fixed and made part of Daniel's bugfix. TODO: 1. perf interface. Not sure if this is needed 2. Latency histograms - process wakeup latency Binoy Binoy Jayan (2): tracing: Add trace_irqsoff tracepoints tracing: Histogram for missed timer offsets Daniel Wagner (1): tracing: Deference pointers without RCU checks include/linux/hrtimer.h | 3 ++ include/linux/rculist.h | 36 ++++++++++++++++++++ include/linux/tracepoint.h | 4 +-- include/trace/events/latency.h | 68 +++++++++++++++++++++++++++++++++++++ kernel/time/hrtimer.c | 39 +++++++++++++++++++++ kernel/trace/trace_events_filter.c | 4 +-- kernel/trace/trace_events_trigger.c | 6 ++-- kernel/trace/trace_irqsoff.c | 45 +++++++++++++++++++++++- 8 files changed, 197 insertions(+), 8 deletions(-) create mode 100644 include/trace/events/latency.h -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
