dtrace - Dtrace compatible user application static probe generation tool.
dtrace -s file [OPTIONS]
The dtrace command converts probe descriptions defined in
file.d into a
probe header file via the
-h option or a probe description file via the
-G option.
- -h
- generate a systemtap header file.
- -G
- generate a systemtap probe definition object file.
- -o file
- is the name of the output file. If the -G option is
given then the output file will be called file.o; if the -h
option is given then the output file will be called file.h.
- -C
- run the cpp preprocessor on the input file when the
-h option is given.
- -I file
- give this include path to cpp when the -C option is
given.
- -k
- keep temporary files, for example the C language source for
the -G option.
Systemtap is source compatible with dtrace user application static probe
support. Given a file
test.d containing:
provider sdt_probes
{
probe test_0 (int type);
probe test_1 (struct astruct node);
};
struct astruct {int a; int b;};
Then the command
"dtrace -s test.d -G"
will create the probe definition file
test.o and the command
"dtrace -stest.d -h" will create the probe
header file
test.h Subsequently the application can use the generated
macros this way:
#include "test.h"
...
struct astruct s;
...
SDT_PROBES_TEST_0(value);
...
if (SDT_PROBES_TEST_1_ENABLED())
SDT_PROBES_TEST_1(expensive_function(s));
Semaphores are flag variables used by probes as a way of bypassing potentially
costly processing to prepare arguments for probes that may not even be active.
They are automatically set/cleared by systemtap when a relevant script is
running, so the argument setup cost is only paid when necessary. These
semaphore variables are defined within the the
"test.o"
object file, which must therefore be linked into an application.
Sometimes, semaphore variables are not necessary nor helpful. Skipping them can
simplify the build process, by omitting the extra
"test.o"
file. To skip dependence upon semaphore variables, include
"<sys/sdt.h>" within the application before
"test.h":
#include <sys/sdt.h>
#include "test.h"
...
struct astruct s;
...
SDT_PROBES_TEST_0(value);
...
if (SDT_PROBES_TEST_1_ENABLED())
SDT_PROBES_TEST_1(cheap_function(s));
In this mode, the ENABLED() test is fixed at 1.
stap(1),
stappaths(7)
Use the Bugzilla link of the project web page or our mailing list.
http://sourceware.org/systemtap/,
<[email protected]>.
error::reporting(7stap),
https://sourceware.org/systemtap/wiki/HowToReportBugs