linux-kernel - [PATCH 2/2] perf env: Cache the arch specific strerrno function in perf_env__arch

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Message-ID: <20231201203046.486596-3-acme@kernel.org>
Date:   Fri,  1 Dec 2023 17:30:46 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Clark Williams <williams@...hat.com>,
        Kate Carcia <kcarcia@...hat.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        David Laight <David.Laight@...LAB.COM>
Subject: [PATCH 2/2] perf env: Cache the arch specific strerrno function in perf_env__arch_strerrno()

From: Arnaldo Carvalho de Melo <acme@...hat.com>

So that we don't have to go thru the series of strcmp(arch) calls for
each id -> string translation.

Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: David Laight <David.Laight@...LAB.COM>
Cc: Ian Rogers <irogers@...gle.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/trace/beauty/arch_errno_names.sh | 6 +++---
 tools/perf/trace/beauty/beauty.h            | 2 --
 tools/perf/util/env.c                       | 6 ++++--
 tools/perf/util/env.h                       | 5 +++++
 4 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/tools/perf/trace/beauty/arch_errno_names.sh b/tools/perf/trace/beauty/arch_errno_names.sh
index b6e0767b4b34e46a..7df4bf5b55a3cc2a 100755
--- a/tools/perf/trace/beauty/arch_errno_names.sh
+++ b/tools/perf/trace/beauty/arch_errno_names.sh
@@ -57,13 +57,13 @@ create_arch_errno_table_func()
 	archlist="$1"
 	default="$2"
 
-	printf 'const char *arch_syscalls__strerrno(const char *arch, int err)\n'
+	printf 'arch_syscalls__strerrno_t *arch_syscalls__strerrno_function(const char *arch)\n'
 	printf '{\n'
 	for arch in $archlist; do
 		printf '\tif (!strcmp(arch, "%s"))\n' $(arch_string "$arch")
-		printf '\t\treturn errno_to_name__%s(err);\n' $(arch_string "$arch")
+		printf '\t\treturn errno_to_name__%s;\n' $(arch_string "$arch")
 	done
-	printf '\treturn errno_to_name__%s(err);\n' $(arch_string "$default")
+	printf '\treturn errno_to_name__%s;\n' $(arch_string "$default")
 	printf '}\n'
 }
 
diff --git a/tools/perf/trace/beauty/beauty.h b/tools/perf/trace/beauty/beauty.h
index 788e8f6bd90eb753..9feb794f5c6e15f4 100644
--- a/tools/perf/trace/beauty/beauty.h
+++ b/tools/perf/trace/beauty/beauty.h
@@ -251,6 +251,4 @@ size_t open__scnprintf_flags(unsigned long flags, char *bf, size_t size, bool sh
 void syscall_arg__set_ret_scnprintf(struct syscall_arg *arg,
 				    size_t (*ret_scnprintf)(char *bf, size_t size, struct syscall_arg *arg));
 
-const char *arch_syscalls__strerrno(const char *arch, int err);
-
 #endif /* _PERF_TRACE_BEAUTY_H */
diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index fdd62ea00173ccf5..2845b9f4694591be 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -456,8 +456,10 @@ const char *perf_env__arch(struct perf_env *env)
 
 const char *perf_env__arch_strerrno(struct perf_env *env, int err)
 {
-	const char *arch_name = perf_env__arch(env);
-	return arch_syscalls__strerrno(arch_name, err);
+	if (env->arch_strerrno == NULL)
+		env->arch_strerrno = arch_syscalls__strerrno_function(perf_env__arch(env));
+
+	return env->arch_strerrno ? env->arch_strerrno(err) : "no arch specific strerrno function";
 }
 
 const char *perf_env__cpuid(struct perf_env *env)
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 79f371879f45bafc..bf7e3c4c211f971e 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -53,6 +53,10 @@ struct pmu_caps {
 	char            *pmu_name;
 };
 
+typedef const char *(arch_syscalls__strerrno_t)(int err);
+
+arch_syscalls__strerrno_t *arch_syscalls__strerrno_function(const char *arch);
+
 struct perf_env {
 	char			*hostname;
 	char			*os_release;
@@ -135,6 +139,7 @@ struct perf_env {
 		 */
 		bool	enabled;
 	} clock;
+	arch_syscalls__strerrno_t *arch_strerrno;
 };
 
 enum perf_compress_type {
-- 
2.41.0