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perf record: Add support for sampling taken branch

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This patch adds a new option to enable taken branch stack
sampling, i.e., leverage the PERF_SAMPLE_BRANCH_STACK feature
of perf_events.

There is a new option to active this mode: -b.
It is possible to pass a set of filters to select the type of
branches to sample.

The following filters are available:

 - any : any type of branches
 - any_call : any function call or system call
 - any_ret : any function return or system call return
 - any_ind : any indirect branch
 - u:  only when the branch target is at the user level
 - k: only when the branch target is in the kernel
 - hv: only when the branch target is in the hypervisor

Filters can be combined by passing a comma separated list
to the option:

$ perf record -b any_call,u -e cycles:u branchy

Signed-off-by: Roberto Agostino Vitillo <ravitillo@lbl.gov>
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-13-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Roberto Agostino Vitillo
2012-02-09 23:21:02 +01:00
committed by Ingo Molnar
parent b5387528f3
commit bdfebd848f
4 changed files with 104 additions and 0 deletions
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74
tools/perf/builtin-record.c
View File

@ -638,6 +638,77 @@ out_delete_session:
return err;
}
#define BRANCH_OPT(n, m) \
{ .name = n, .mode = (m) }
#define BRANCH_END { .name = NULL }
struct branch_mode {
const char *name;
int mode;
};
static const struct branch_mode branch_modes[] = {
BRANCH_OPT("u", PERF_SAMPLE_BRANCH_USER),
BRANCH_OPT("k", PERF_SAMPLE_BRANCH_KERNEL),
BRANCH_OPT("hv", PERF_SAMPLE_BRANCH_HV),
BRANCH_OPT("any", PERF_SAMPLE_BRANCH_ANY),
BRANCH_OPT("any_call", PERF_SAMPLE_BRANCH_ANY_CALL),
BRANCH_OPT("any_ret", PERF_SAMPLE_BRANCH_ANY_RETURN),
BRANCH_OPT("ind_call", PERF_SAMPLE_BRANCH_IND_CALL),
BRANCH_END
};
static int
parse_branch_stack(const struct option *opt, const char *str, int unset __used)
{
#define ONLY_PLM \
(PERF_SAMPLE_BRANCH_USER |\
PERF_SAMPLE_BRANCH_KERNEL |\
PERF_SAMPLE_BRANCH_HV)
uint64_t *mode = (uint64_t *)opt->value;
const struct branch_mode *br;
char *s, *os, *p;
int ret = -1;
*mode = 0;
/* because str is read-only */
s = os = strdup(str);
if (!s)
return -1;
for (;;) {
p = strchr(s, ',');
if (p)
*p = '\0';
for (br = branch_modes; br->name; br++) {
if (!strcasecmp(s, br->name))
break;
}
if (!br->name)
goto error;
*mode |= br->mode;
if (!p)
break;
s = p + 1;
}
ret = 0;
if ((*mode & ~ONLY_PLM) == 0) {
error("need at least one branch type with -b\n");
ret = -1;
}
error:
free(os);
return ret;
}
static const char * const record_usage[] = {
"perf record [<options>] [<command>]",
"perf record [<options>] -- <command> [<options>]",
@ -727,6 +798,9 @@ const struct option record_options[] = {
"monitor event in cgroup name only",
parse_cgroups),
OPT_STRING('u', "uid", &record.uid_str, "user", "user to profile"),
OPT_CALLBACK('b', "branch-stack", &record.opts.branch_stack,
"branch mode mask", "branch stack sampling modes",
parse_branch_stack),
OPT_END()
};