lkml.org 
[lkml]   [2016]   [Aug]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH v4 0/3] *** Latency histograms - IRQSOFF,PREEMPTOFF ***
Date
Hi,

Thank you Daniel for reviewing v3 throroughly.
These set of patches [v4] capture latency events caused by interrupts and
premption disabled in kernel. The patches are based on the hist trigger
feature developed by Tom Zanussi.

v3: https://lkml.org/lkml/2016/8/29/50
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 v3 as per comments from Daniel
- A few coding style changes
- Dropped the field 'cpu' from the event format fields.

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 | 64 +++++++++++++++++++++++++++++++++++++
kernel/time/hrtimer.c | 40 +++++++++++++++++++++++
kernel/trace/trace_events_filter.c | 4 +--
kernel/trace/trace_events_trigger.c | 6 ++--
kernel/trace/trace_irqsoff.c | 42 ++++++++++++++++++++++++
8 files changed, 192 insertions(+), 7 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

\
 
 \ /
  Last update: 2016-09-17 09:58    [W:0.102 / U:0.544 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site