HP Caliper Ktrace Features Guide

Table 2-1 ktracer options (continued)
DescriptionOption
Uninsert. Remove all trace points.
The -U uninsert option reverses the effect of -I (insert).
-U
Remove all functions from function list.
-z
Managing Memory for Traces - Each trace record shows as one line in the ktracedump output. Each
CPU has a circular trace buffer. ktracer defaults to collecting 2048 traces per CPU. Use the ktracer
-A option to increase or decrease the number of traces per CPU. After the trace buffer is filled with trace
records, the oldest trace is overwritten and lost. The most recent numtraces are preserved in the trace
buffer until ktracer —f frees them, or until ktracer —Z or ktracer —A initializes them to zero, or
until the system is shutdown. If a dump is taken prior to reboot, the trace buffers will be saved in the
dump, and ktracedump may be run in the dump directory to report their content.
Allocate trace buffers in kernel memory that are large enough to hold
numtraces trace records per CPU. numtraces is an integer argument. The
default is 2048 traces. The maximum number of traces per CPU is 6,000,000.
The —A option does not turn on tracing. To turn on tracing, use —R, —L, —b, or
—B.
—A numtraces
Zero the trace buffers. Clear the contents of all the per-CPU trace buffers.
—Z
Free the memory allocated by ktracer, namely the per CPU trace buffers
and the function list. After completing a session of kernel tracing and
ktracedump report generation, invoking —f is recommended, particularly
if not much physical memory is available on the system.
-f
General Interest
Display ktracer usage message-?
Display current status of ktracer. Sample status:
ON; Trace ACTIVE; Funcs INSTALLED; ALLOCATED;
The first status element is ON or OFF. ktracer is turned ON explicitly by
-b or -B or implicitly by -L or -R. ktracer is turned OFF explicitly by -h
or implicitly by -a, -A, -r, —S, —U, -z, or -Z. ktracer can also be
turned off when a STOP function is executed. See -S.
The second status element is "Trace ACTIVE" or "Trace NOT active.”
The third status element is "Funcs INSTALLED" or "Funcs NOT installed".
Functions are installed explicitly by -I or implicity by -L, -R, -B or -b.
Functions are not installed explicitly by -U or implicitly by —a, —h, —r, —S,
—z, or —Z.
The fourth status element is "ALLOCATED" or "NOT allocated". Memory is
allocated explicitly by -A or implicitly by -L or -R. Memory is freed explicitly
by -f.
-t
22 ktracer: Kernel Tracer