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perf probe: Support tracing an entry of array

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Add array-entry tracing support to perf probe. This enables to trace an entry
of array which is indexed by constant value, e.g. array[0].

For example:

  $ perf probe -a 'bio_split bi->bi_io_vec[0]'

Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100519195742.2885.5344.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu
2010-05-19 15:57:42 -04:00
committed by Arnaldo Carvalho de Melo
parent 73317b9540
commit b2a3c12b74
4 changed files with 82 additions and 23 deletions
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56
tools/perf/util/probe-event.c
View File

@@ -557,7 +557,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
/* Parse perf-probe event argument */
static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
{
char *tmp;
char *tmp, *goodname;
struct perf_probe_arg_field **fieldp;
pr_debug("parsing arg: %s into ", str);
@@ -580,7 +580,7 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
pr_debug("type:%s ", arg->type);
}
tmp = strpbrk(str, "-.");
tmp = strpbrk(str, "-.[");
if (!is_c_varname(str) || !tmp) {
/* A variable, register, symbol or special value */
arg->var = strdup(str);
@@ -590,10 +590,11 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
return 0;
}
/* Structure fields */
/* Structure fields or array element */
arg->var = strndup(str, tmp - str);
if (arg->var == NULL)
return -ENOMEM;
goodname = arg->var;
pr_debug("%s, ", arg->var);
fieldp = &arg->field;
@@ -601,22 +602,38 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
*fieldp = zalloc(sizeof(struct perf_probe_arg_field));
if (*fieldp == NULL)
return -ENOMEM;
if (*tmp == '.') {
str = tmp + 1;
(*fieldp)->ref = false;
} else if (tmp[1] == '>') {
str = tmp + 2;
if (*tmp == '[') { /* Array */
str = tmp;
(*fieldp)->index = strtol(str + 1, &tmp, 0);
(*fieldp)->ref = true;
} else {
semantic_error("Argument parse error: %s\n", str);
return -EINVAL;
if (*tmp != ']' || tmp == str + 1) {
semantic_error("Array index must be a"
" number.\n");
return -EINVAL;
}
tmp++;
if (*tmp == '\0')
tmp = NULL;
} else { /* Structure */
if (*tmp == '.') {
str = tmp + 1;
(*fieldp)->ref = false;
} else if (tmp[1] == '>') {
str = tmp + 2;
(*fieldp)->ref = true;
} else {
semantic_error("Argument parse error: %s\n",
str);
return -EINVAL;
}
tmp = strpbrk(str, "-.[");
}
tmp = strpbrk(str, "-.");
if (tmp) {
(*fieldp)->name = strndup(str, tmp - str);
if ((*fieldp)->name == NULL)
return -ENOMEM;
if (*str != '[')
goodname = (*fieldp)->name;
pr_debug("%s(%d), ", (*fieldp)->name, (*fieldp)->ref);
fieldp = &(*fieldp)->next;
}
@@ -624,11 +641,13 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
(*fieldp)->name = strdup(str);
if ((*fieldp)->name == NULL)
return -ENOMEM;
if (*str != '[')
goodname = (*fieldp)->name;
pr_debug("%s(%d)\n", (*fieldp)->name, (*fieldp)->ref);
/* If no name is specified, set the last field name */
/* If no name is specified, set the last field name (not array index)*/
if (!arg->name) {
arg->name = strdup((*fieldp)->name);
arg->name = strdup(goodname);
if (arg->name == NULL)
return -ENOMEM;
}
@@ -776,8 +795,11 @@ int synthesize_perf_probe_arg(struct perf_probe_arg *pa, char *buf, size_t len)
len -= ret;
while (field) {
ret = e_snprintf(tmp, len, "%s%s", field->ref ? "->" : ".",
field->name);
if (field->name[0] == '[')
ret = e_snprintf(tmp, len, "%s", field->name);
else
ret = e_snprintf(tmp, len, "%s%s",
field->ref ? "->" : ".", field->name);
if (ret <= 0)
goto error;
tmp += ret;