[PATCH v1 3/5] perf evlist: Refactor evlist__scnprintf_evsels

Ian Rogers
2025-03-18T04:14:55Z

Switch output to using a strbuf so the storage can be resized. Rename
as scnprintf is no longer used.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/builtin-record.c | 9 ++++++---
tools/perf/util/evlist.c | 19 +++++++++----------
tools/perf/util/evlist.h | 3 ++-
3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index ba20bf7c011d..cea5959adadc 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -51,6 +51,7 @@
#include "util/clockid.h"
#include "util/off_cpu.h"
#include "util/bpf-filter.h"
+#include "util/strbuf.h"
#include "asm/bug.h"
#include "perf.h"
#include "cputopo.h"
@@ -2784,13 +2785,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
record__auxtrace_snapshot_exit(rec);

if (forks && workload_exec_errno) {
- char msg[STRERR_BUFSIZE], strevsels[2048];
+ char msg[STRERR_BUFSIZE];
const char *emsg = str_error_r(workload_exec_errno, msg, sizeof(msg));
+ struct strbuf sb = STRBUF_INIT;

- evlist__scnprintf_evsels(rec->evlist, sizeof(strevsels), strevsels);
+ evlist__format_evsels(rec->evlist, &sb);

pr_err("Failed to collect '%s' for the '%s' workload: %s\n",
- strevsels, argv[0], emsg);
+ sb.buf, argv[0], emsg);
+ strbuf_release(&sb);
err = -1;
goto out_child;
}
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 49e10d6981ad..96cfc7ed1512 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -35,6 +35,7 @@
#include "util/util.h"
#include "util/env.h"
#include "util/intel-tpebs.h"
+#include "util/strbuf.h"
#include <signal.h>
#include <unistd.h>
#include <sched.h>
@@ -2468,23 +2469,21 @@ struct evsel *evlist__find_evsel(struct evlist *evlist, int idx)
return NULL;
}

-int evlist__scnprintf_evsels(struct evlist *evlist, size_t size, char *bf)
+void evlist__format_evsels(struct evlist *evlist, struct strbuf *sb)
{
struct evsel *evsel;
- int printed = 0;
+ bool first = true;

evlist__for_each_entry(evlist, evsel) {
if (evsel__is_dummy_event(evsel))
continue;
- if (size > (strlen(evsel__name(evsel)) + (printed ? 2 : 1))) {
- printed += scnprintf(bf + printed, size - printed, "%s%s", printed ? "," : "", evsel__name(evsel));
- } else {
- printed += scnprintf(bf + printed, size - printed, "%s...", printed ? "," : "");
- break;
- }
- }

- return printed;
+ if (!first)
+ strbuf_addch(sb, ',');
+
+ strbuf_addstr(sb, evsel__name(evsel));
+ first = false;
+ }
}

void evlist__check_mem_load_aux(struct evlist *evlist)
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index edcbf1c10e92..5fe5cfbbebb1 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -20,6 +20,7 @@ struct pollfd;
struct thread_map;
struct perf_cpu_map;
struct record_opts;
+struct strbuf;
struct target;

/*
@@ -430,7 +431,7 @@ int event_enable_timer__process(struct event_enable_timer *eet);

struct evsel *evlist__find_evsel(struct evlist *evlist, int idx);

-int evlist__scnprintf_evsels(struct evlist *evlist, size_t size, char *bf);
+void evlist__format_evsels(struct evlist *evlist, struct strbuf *sb);
void evlist__check_mem_load_aux(struct evlist *evlist);
void evlist__warn_user_requested_cpus(struct evlist *evlist, const char *cpu_list);
void evlist__uniquify_name(struct evlist *evlist);
--
2.49.0.rc1.451.g8f38331e32-goog