[PATCH v5 1/2] perf pmus: Sort pmus by name then suffix

Ian Rogers
2023-08-25T13:53:51Z

Sort PMUs by name. If two PMUs have the same name but differ by
suffix, sort the suffixes numerically. For example, "breakpoint" comes
before "cpu", "uncore_imc_free_running_0" comes before
"uncore_imc_free_running_1". Suffixes need to be treated specially as
otherwise they will be ordered like 0, 1, 10, 11, .., 2, 20, 21, ..,
etc. Only PMUs starting 'uncore_' are considered to have a potential
suffix.

Sorting of PMUs is done so that later patches can skip duplicate
uncore PMUs that differ only by there suffix.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/pmus.c | 48 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
index 4dd5912617ff..b1f6a64693fe 100644
--- a/tools/perf/util/pmus.c
+++ b/tools/perf/util/pmus.c
@@ -1,8 +1,10 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/list.h>
+#include <linux/list_sort.h>
#include <linux/zalloc.h>
#include <subcmd/pager.h>
#include <sys/types.h>
+#include <ctype.h>
#include <dirent.h>
#include <pthread.h>
#include <string.h>
@@ -33,6 +35,31 @@ static LIST_HEAD(other_pmus);
static bool read_sysfs_core_pmus;
static bool read_sysfs_all_pmus;

+static int pmu_name_len_no_suffix(const char *str, unsigned long *num)
+{
+ int orig_len, len;
+
+ orig_len = len = strlen(str);
+
+ /* Non-uncore PMUs have their full length, for example, i915. */
+ if (strncmp(str, "uncore_", 7))
+ return len;
+
+ /*
+ * Count trailing digits and '_', if '_{num}' suffix isn't present use
+ * the full length.
+ */
+ while (len > 0 && isdigit(str[len - 1]))
+ len--;
+
+ if (len > 0 && len != orig_len && str[len - 1] == '_') {
+ if (num)
+ *num = strtoul(&str[len], NULL, 10);
+ return len - 1;
+ }
+ return orig_len;
+}
+
void perf_pmus__destroy(void)
{
struct perf_pmu *pmu, *tmp;
@@ -122,6 +149,25 @@ static struct perf_pmu *perf_pmu__find2(int dirfd, const char *name)
return perf_pmu__lookup(core_pmu ? &core_pmus : &other_pmus, dirfd, name);
}

+static int pmus_cmp(void *priv __maybe_unused,
+ const struct list_head *lhs, const struct list_head *rhs)
+{
+ unsigned long lhs_num, rhs_num;
+ struct perf_pmu *lhs_pmu = container_of(lhs, struct perf_pmu, list);
+ struct perf_pmu *rhs_pmu = container_of(rhs, struct perf_pmu, list);
+ const char *lhs_pmu_name = lhs_pmu->name ?: "";
+ const char *rhs_pmu_name = rhs_pmu->name ?: "";
+ int lhs_pmu_name_len = pmu_name_len_no_suffix(lhs_pmu_name, &lhs_num);
+ int rhs_pmu_name_len = pmu_name_len_no_suffix(rhs_pmu_name, &rhs_num);
+ int ret = strncmp(lhs_pmu_name, rhs_pmu_name,
+ lhs_pmu_name_len < rhs_pmu_name_len ? lhs_pmu_name_len : rhs_pmu_name_len);
+
+ if (lhs_pmu_name_len != rhs_pmu_name_len || ret != 0 || lhs_pmu_name_len == 0)
+ return ret;
+
+ return lhs_num < rhs_num ? -1 : (lhs_num > rhs_num ? 1 : 0);
+}
+
/* Add all pmus in sysfs to pmu list: */
static void pmu_read_sysfs(bool core_only)
{
@@ -156,6 +202,8 @@ static void pmu_read_sysfs(bool core_only)
if (!perf_pmu__create_placeholder_core_pmu(&core_pmus))
pr_err("Failure to set up any core PMUs\n");
}
+ list_sort(NULL, &core_pmus, pmus_cmp);
+ list_sort(NULL, &other_pmus, pmus_cmp);
if (!list_empty(&core_pmus)) {
read_sysfs_core_pmus = true;
if (!core_only)
--
2.42.0.rc2.253.gd59a3bf2b4-goog