Bug 716559

Summary: RT Tuning Guide update
Product: Red Hat Enterprise MRG Reporter: Beth Uptagrafft <bhu>
Component: Realtime_Tuning_GuideAssignee: Alison Young <alyoung>
Status: CLOSED CURRENTRELEASE QA Contact: Jeff Needle <jneedle>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 2.0CC: davids, jkacur, jneedle, lbrindle, lgoncalv, williams
Target Milestone: 2.1Keywords: Documentation
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
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Fixed In Version: Doc Type: Bug Fix
Doc Text:
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Clone Of: Environment:
Last Closed: 2012-01-26 19:30:51 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 733203    
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Description Flags
ftrace documentation
none
Event Tracing Documentation none

Description Beth Uptagrafft 2011-06-24 21:18:06 UTC 
Created attachment 509846 [details]
ftrace documentation

ftrace.txt and events.txt are new docs that Steven updated for MRG Documentation/trace/*.  RT Engineering needs to determine what to fold into our Tuning Guide.
Comment 1 Beth Uptagrafft 2011-06-24 21:19:28 UTC 
Created attachment 509847 [details]
Event Tracing Documentation
Comment 2 Alison Young 2011-08-23 01:42:26 UTC 
Hi Beth,

Have RT Engineering got a better idea about what to include and leave out from the attached documentation yet? Feel free to redirect the needinfo.

Thanks,
Alison
Comment 3 John Kacur 2011-08-30 12:35:22 UTC 
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_MRG/2.0/html-single/Realtime_Tuning_Guide/index.html#sect-Realtime_Tuning_Guide-Realtime_Specific_Tuning-Using_the_ftrace_Utility_for_Tracing_Latencies

The "events" are no longer correct in this version.
The following comments refer to the ftrace section of the guide

Remove "events" from the line below

# cat /sys/kernel/debug/tracing/available_tracers
events wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none

Remove the following section.

events
    Traces system events such as timers, system calls, interrupts, context switches, process wake up and others

In the following section substitute "preemptoff" for "events"
# echo events > /sys/kernel/debug/tracing/current_tracer

In 5. View the trace logs: 

Remove the following line
# cat /sys/kernel/debug/tracing//latency_trace

In 6.
Change
# cat /sys/kernel/debug/tracing//latency_trace > /tmp/lat_trace_log
to
# cat /sys/kernel/debug/tracing/trace > /tmp/trace_log
Comment 13 Lana Brindley 2012-01-26 19:30:51 UTC 
This book is now available on redhat.com/docs. Please raise a new bug if you spot any issues.

Thanks,
LKB