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libtracefs(3)
=============
NAME
----
tracefs_hist_start, tracefs_hist_destroy, tracefs_hist_pause,
tracefs_hist_continue, tracefs_hist_reset - Pause, continue, or clear an existing histogram
SYNOPSIS
--------
[verse]
--
*#include <tracefs.h>*
int *tracefs_hist_start*(struct tracefs_instance pass:[*]_instance_, struct tracefs_hist pass:[*]_hist_);
int *tracefs_hist_destroy*(struct tracefs_instance pass:[*]_instance_, struct tracefs_hist pass:[*]_hist_);
int *tracefs_hist_pause*(struct tracefs_instance pass:[*]_instance_, struct tracefs_hist pass:[*]_hist_);
int *tracefs_hist_continue*(struct tracefs_instance pass:[*]_instance_, struct tracefs_hist pass:[*]_hist_);
int *tracefs_hist_reset*(struct tracefs_instance pass:[*]_instance_, struct tracefs_hist pass:[*]_hist_);
--
DESCRIPTION
-----------
*tracefs_hist_start()* is called to actually start the histogram _hist_.
The _instance_ is the instance to start the histogram in, NULL if it
should start at the top level.
*tracefs_hist_pause()* is called to pause the histogram _hist_.
The _instance_ is the instance to pause the histogram in, NULL if it
is in the top level.
*tracefs_hist_continue()* is called to continue a paused histogram _hist_.
The _instance_ is the instance to continue the histogram, NULL if it
is in the top level.
*tracefs_hist_reset()* is called to clear / reset the histogram _hist_.
The _instance_ is the instance to clear the histogram, NULL if it
is in the top level.
*tracefs_hist_destroy()* is called to delete the histogram where it will no longer
exist. The _instance_ is the instance to delete the histogram from, NULL if it
is in the top level.
RETURN VALUE
------------
All the return zero on success or -1 on error.
EXAMPLE
-------
[source,c]
--
#include <stdlib.h>
#include <tracefs.h>
enum commands {
START,
PAUSE,
CONT,
RESET,
DELETE,
SHOW,
};
int main (int argc, char **argv, char **env)
{
struct tracefs_instance *instance;
struct tracefs_hist *hist;
struct tep_handle *tep;
enum commands cmd;
char *cmd_str;
int ret;
if (argc < 2) {
fprintf(stderr, "usage: %s command\n", argv[0]);
exit(-1);
}
cmd_str = argv[1];
if (!strcmp(cmd_str, "start"))
cmd = START;
else if (!strcmp(cmd_str, "pause"))
cmd = PAUSE;
else if (!strcmp(cmd_str, "cont"))
cmd = CONT;
else if (!strcmp(cmd_str, "reset"))
cmd = RESET;
else if (!strcmp(cmd_str, "delete"))
cmd = DELETE;
else if (!strcmp(cmd_str, "show"))
cmd = SHOW;
else {
fprintf(stderr, "Unknown command %s\n", cmd_str);
exit(-1);
}
tep = tracefs_local_events(NULL);
if (!tep) {
perror("Reading tracefs");
exit(-1);
}
instance = tracefs_instance_create("hist_test");
if (!instance) {
fprintf(stderr, "Failed instance create\n");
exit(-1);
}
hist = tracefs_hist_alloc_2d(tep, "kmem", "kmalloc",
"call_site",TRACEFS_HIST_KEY_SYM,
"bytes_req", 0);
if (!hist) {
fprintf(stderr, "Failed hist create\n");
exit(-1);
}
ret = tracefs_hist_add_value(hist, "bytes_alloc");
ret |= tracefs_hist_add_sort_key(hist, "bytes_req");
ret |= tracefs_hist_add_sort_key(hist, "bytes_alloc");
ret |= tracefs_hist_sort_key_direction(hist, "bytes_alloc",
TRACEFS_HIST_SORT_DESCENDING);
if (ret) {
fprintf(stderr, "Failed modifying histogram\n");
exit(-1);
}
tracefs_error_clear(instance);
switch (cmd) {
case START:
ret = tracefs_hist_start(instance, hist);
if (ret) {
char *err = tracefs_error_last(instance);
if (err)
fprintf(stderr, "\n%s\n", err);
}
break;
case PAUSE:
ret = tracefs_hist_pause(instance, hist);
break;
case CONT:
ret = tracefs_hist_continue(instance, hist);
break;
case RESET:
ret = tracefs_hist_reset(instance, hist);
break;
case DELETE:
ret = tracefs_hist_destroy(instance, hist);
break;
case SHOW: {
char *content;
content = tracefs_event_file_read(instance, "kmem", "kmalloc",
"hist", NULL);
ret = content ? 0 : -1;
if (content) {
printf("%s\n", content);
free(content);
}
break;
}
}
if (ret)
fprintf(stderr, "Failed: command\n");
exit(ret);
}
--
FILES
-----
[verse]
--
*tracefs.h*
Header file to include in order to have access to the library APIs.
*-ltracefs*
Linker switch to add when building a program that uses the library.
--
SEE ALSO
--------
*libtracefs*(3),
*libtraceevent*(3),
*trace-cmd*(1),
*tracefs_hist_alloc*(3),
*tracefs_hist_alloc_2d*(3),
*tracefs_hist_alloc_nd*(3),
*tracefs_hist_free*(3),
*tracefs_hist_add_key*(3),
*tracefs_hist_add_value*(3),
*tracefs_hist_add_name*(3),
*tracefs_hist_start*(3),
*tracefs_hist_destory*(3),
*tracefs_hist_add_sort_key*(3),
*tracefs_hist_sort_key_direction*(3)
AUTHOR
------
[verse]
--
*Steven Rostedt* <rostedt@goodmis.org>
*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>
*sameeruddin shaik* <sameeruddin.shaik8@gmail.com>
--
REPORTING BUGS
--------------
Report bugs to <linux-trace-devel@vger.kernel.org>
LICENSE
-------
libtracefs is Free Software licensed under the GNU LGPL 2.1
RESOURCES
---------
https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
COPYING
-------
Copyright \(C) 2020 VMware, Inc. Free use of this software is granted under
the terms of the GNU Public License (GPL).
|
