linux/tools/perf/util/topdown.c
Kan Liang acb65150a4 perf record: Support sample-read topdown metric group
With the hardware TopDown metrics feature, sample-read feature should be
supported for a topdown group, e.g., sample a non-topdown event and read
a topdown metric group. But the current perf record code errors out.

For a topdown metric group, the slots event must be the leader of the
group, but the leader slots event doesn't support sampling.

To support sample-read the topdown metric group, use the 2nd event of
the group as the "leader" for the purposes of sampling.

Only the platform with Topdown metic feature supports sample-read the
topdown group. Add arch_topdown_sample_read() to indicate whether the
topdown group supports sample-read.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200911144808.27603-3-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-09-17 15:47:58 -03:00

59 lines
920 B
C

// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include "pmu.h"
#include "topdown.h"
int topdown_filter_events(const char **attr, char **str, bool use_group)
{
int off = 0;
int i;
int len = 0;
char *s;
for (i = 0; attr[i]; i++) {
if (pmu_have_event("cpu", attr[i])) {
len += strlen(attr[i]) + 1;
attr[i - off] = attr[i];
} else
off++;
}
attr[i - off] = NULL;
*str = malloc(len + 1 + 2);
if (!*str)
return -1;
s = *str;
if (i - off == 0) {
*s = 0;
return 0;
}
if (use_group)
*s++ = '{';
for (i = 0; attr[i]; i++) {
strcpy(s, attr[i]);
s += strlen(s);
*s++ = ',';
}
if (use_group) {
s[-1] = '}';
*s = 0;
} else
s[-1] = 0;
return 0;
}
__weak bool arch_topdown_check_group(bool *warn)
{
*warn = false;
return false;
}
__weak void arch_topdown_group_warn(void)
{
}
__weak bool arch_topdown_sample_read(struct evsel *leader __maybe_unused)
{
return false;
}