sysconf(_SC_NPROCESSORS_CONF) (via get_nprocs_conf) reflects
cpu_possible_mask, which is fixed at boot time, so querying it
repeatedly is unnecessary.

Replace multiple calls to sysconf(_SC_NPROCESSORS_CONF) with a single
global nr_cpus variable initialized once at startup.

`#pragma once` in timerlat_u.h is needed for pre-C23 compilers to avoid
redefinition errors.

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
---
 tools/tracing/rtla/src/common.c        |  7 +++++--
 tools/tracing/rtla/src/common.h        |  2 ++
 tools/tracing/rtla/src/osnoise_hist.c  |  3 ---
 tools/tracing/rtla/src/osnoise_top.c   |  7 -------
 tools/tracing/rtla/src/timerlat.c      |  5 +----
 tools/tracing/rtla/src/timerlat_aa.c   |  1 -
 tools/tracing/rtla/src/timerlat_hist.c |  3 ---
 tools/tracing/rtla/src/timerlat_top.c  |  7 -------
 tools/tracing/rtla/src/timerlat_u.c    |  3 +--
 tools/tracing/rtla/src/timerlat_u.h    |  1 +
 tools/tracing/rtla/src/utils.c         | 10 +---------
 11 files changed, 11 insertions(+), 38 deletions(-)

diff --git a/tools/tracing/rtla/src/common.c b/tools/tracing/rtla/src/common.c
index ceff76a62a30..e4cf30a65e82 100644
--- a/tools/tracing/rtla/src/common.c
+++ b/tools/tracing/rtla/src/common.c
@@ -5,12 +5,14 @@
 #include <signal.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 #include <getopt.h>
+#include <sys/sysinfo.h>
+
 #include "common.h"
 
 struct trace_instance *trace_inst;
 volatile int stop_tracing;
+int nr_cpus;
 
 static void stop_trace(int sig)
 {
@@ -135,7 +137,7 @@ common_apply_config(struct osnoise_tool *tool, struct common_params *params)
 	}
 
 	if (!params->cpus) {
-		for (i = 0; i < sysconf(_SC_NPROCESSORS_CONF); i++)
+		for (i = 0; i < nr_cpus; i++)
 			CPU_SET(i, &params->monitored_cpus);
 	}
 
@@ -183,6 +185,7 @@ int run_tool(struct tool_ops *ops, int argc, char *argv[])
 	bool stopped;
 	int retval;
 
+	nr_cpus = get_nprocs_conf();
 	params = ops->parse_args(argc, argv);
 	if (!params)
 		exit(1);
diff --git a/tools/tracing/rtla/src/common.h b/tools/tracing/rtla/src/common.h
index 7602c5593ef5..32f9c1351209 100644
--- a/tools/tracing/rtla/src/common.h
+++ b/tools/tracing/rtla/src/common.h
@@ -107,6 +107,8 @@ struct common_params {
 	struct timerlat_u_params user;
 };
 
+extern int nr_cpus;
+
 #define for_each_monitored_cpu(cpu, nr_cpus, common) \
 	for (cpu = 0; cpu < nr_cpus; cpu++) \
 		if (!(common)->cpus || CPU_ISSET(cpu, &(common)->monitored_cpus))
diff --git a/tools/tracing/rtla/src/osnoise_hist.c b/tools/tracing/rtla/src/osnoise_hist.c
index 9d70ea34807f..03ebff34fff4 100644
--- a/tools/tracing/rtla/src/osnoise_hist.c
+++ b/tools/tracing/rtla/src/osnoise_hist.c
@@ -647,9 +647,6 @@ static struct osnoise_tool
 *osnoise_init_hist(struct common_params *params)
 {
 	struct osnoise_tool *tool;
-	int nr_cpus;
-
-	nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 
 	tool = osnoise_init_tool("osnoise_hist");
 	if (!tool)
diff --git a/tools/tracing/rtla/src/osnoise_top.c b/tools/tracing/rtla/src/osnoise_top.c
index d54d47947fb4..7dcd2e318205 100644
--- a/tools/tracing/rtla/src/osnoise_top.c
+++ b/tools/tracing/rtla/src/osnoise_top.c
@@ -232,12 +232,8 @@ osnoise_print_stats(struct osnoise_tool *top)
 {
 	struct osnoise_params *params = to_osnoise_params(top->params);
 	struct trace_instance *trace = &top->trace;
-	static int nr_cpus = -1;
 	int i;
 
-	if (nr_cpus == -1)
-		nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
-
 	if (!params->common.quiet)
 		clear_terminal(trace->seq);
 
@@ -495,9 +491,6 @@ osnoise_top_apply_config(struct osnoise_tool *tool)
 struct osnoise_tool *osnoise_init_top(struct common_params *params)
 {
 	struct osnoise_tool *tool;
-	int nr_cpus;
-
-	nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 
 	tool = osnoise_init_tool("osnoise_top");
 	if (!tool)
diff --git a/tools/tracing/rtla/src/timerlat.c b/tools/tracing/rtla/src/timerlat.c
index 8f8811f7a13b..69856f677fce 100644
--- a/tools/tracing/rtla/src/timerlat.c
+++ b/tools/tracing/rtla/src/timerlat.c
@@ -99,7 +99,7 @@ timerlat_apply_config(struct osnoise_tool *tool, struct timerlat_params *params)
 int timerlat_enable(struct osnoise_tool *tool)
 {
 	struct timerlat_params *params = to_timerlat_params(tool->params);
-	int retval, nr_cpus, i;
+	int retval, i;
 
 	if (params->dma_latency >= 0) {
 		dma_latency_fd = set_cpu_dma_latency(params->dma_latency);
@@ -115,8 +115,6 @@ int timerlat_enable(struct osnoise_tool *tool)
 			return -1;
 		}
 
-		nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
-
 		for_each_monitored_cpu(i, nr_cpus, &params->common) {
 			if (save_cpu_idle_disable_state(i) < 0) {
 				err_msg("Could not save cpu idle state.\n");
@@ -214,7 +212,6 @@ void timerlat_analyze(struct osnoise_tool *tool, bool stopped)
 void timerlat_free(struct osnoise_tool *tool)
 {
 	struct timerlat_params *params = to_timerlat_params(tool->params);
-	int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 	int i;
 
 	timerlat_aa_destroy();
diff --git a/tools/tracing/rtla/src/timerlat_aa.c b/tools/tracing/rtla/src/timerlat_aa.c
index 31e66ea2b144..5766d58709eb 100644
--- a/tools/tracing/rtla/src/timerlat_aa.c
+++ b/tools/tracing/rtla/src/timerlat_aa.c
@@ -1022,7 +1022,6 @@ void timerlat_aa_destroy(void)
  */
 int timerlat_aa_init(struct osnoise_tool *tool, int dump_tasks)
 {
-	int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 	struct timerlat_aa_context *taa_ctx;
 	int retval;
 
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 4e8c38a61197..841118ed84f2 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -1031,9 +1031,6 @@ static struct osnoise_tool
 *timerlat_init_hist(struct common_params *params)
 {
 	struct osnoise_tool *tool;
-	int nr_cpus;
-
-	nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 
 	tool = osnoise_init_tool("timerlat_hist");
 	if (!tool)
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 284b74773c2b..3e395ce4fa9f 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -442,15 +442,11 @@ timerlat_print_stats(struct osnoise_tool *top)
 	struct timerlat_params *params = to_timerlat_params(top->params);
 	struct trace_instance *trace = &top->trace;
 	struct timerlat_top_cpu summary;
-	static int nr_cpus = -1;
 	int i;
 
 	if (params->common.aa_only)
 		return;
 
-	if (nr_cpus == -1)
-		nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
-
 	if (!params->common.quiet)
 		clear_terminal(trace->seq);
 
@@ -781,9 +777,6 @@ static struct osnoise_tool
 *timerlat_init_top(struct common_params *params)
 {
 	struct osnoise_tool *top;
-	int nr_cpus;
-
-	nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 
 	top = osnoise_init_tool("timerlat_top");
 	if (!top)
diff --git a/tools/tracing/rtla/src/timerlat_u.c b/tools/tracing/rtla/src/timerlat_u.c
index ce68e39d25fd..a569fe7f93aa 100644
--- a/tools/tracing/rtla/src/timerlat_u.c
+++ b/tools/tracing/rtla/src/timerlat_u.c
@@ -16,7 +16,7 @@
 #include <sys/wait.h>
 #include <sys/prctl.h>
 
-#include "utils.h"
+#include "common.h"
 #include "timerlat_u.h"
 
 /*
@@ -131,7 +131,6 @@ static int timerlat_u_send_kill(pid_t *procs, int nr_cpus)
  */
 void *timerlat_u_dispatcher(void *data)
 {
-	int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 	struct timerlat_u_params *params = data;
 	char proc_name[128];
 	int procs_count = 0;
diff --git a/tools/tracing/rtla/src/timerlat_u.h b/tools/tracing/rtla/src/timerlat_u.h
index 661511908957..a692331bd1c7 100644
--- a/tools/tracing/rtla/src/timerlat_u.h
+++ b/tools/tracing/rtla/src/timerlat_u.h
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#pragma once
 /*
  * Copyright (C) 2023 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>
  */
diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c
index 0da3b2470c31..8cd1b374b035 100644
--- a/tools/tracing/rtla/src/utils.c
+++ b/tools/tracing/rtla/src/utils.c
@@ -19,7 +19,7 @@
 #include <stdio.h>
 #include <limits.h>
 
-#include "utils.h"
+#include "common.h"
 
 #define MAX_MSG_LENGTH	1024
 int config_debug;
@@ -119,14 +119,11 @@ int parse_cpu_set(char *cpu_list, cpu_set_t *set)
 {
 	const char *p;
 	int end_cpu;
-	int nr_cpus;
 	int cpu;
 	int i;
 
 	CPU_ZERO(set);
 
-	nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
-
 	for (p = cpu_list; *p; ) {
 		cpu = atoi(p);
 		if (cpu < 0 || (!cpu && *p != '0') || cpu >= nr_cpus)
@@ -559,7 +556,6 @@ int save_cpu_idle_disable_state(unsigned int cpu)
 	unsigned int nr_states;
 	unsigned int state;
 	int disabled;
-	int nr_cpus;
 
 	nr_states = cpuidle_state_count(cpu);
 
@@ -567,7 +563,6 @@ int save_cpu_idle_disable_state(unsigned int cpu)
 		return 0;
 
 	if (saved_cpu_idle_disable_state == NULL) {
-		nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 		saved_cpu_idle_disable_state = calloc(nr_cpus, sizeof(unsigned int *));
 		if (!saved_cpu_idle_disable_state)
 			return -1;
@@ -644,13 +639,10 @@ int restore_cpu_idle_disable_state(unsigned int cpu)
 void free_cpu_idle_disable_states(void)
 {
 	int cpu;
-	int nr_cpus;
 
 	if (!saved_cpu_idle_disable_state)
 		return;
 
-	nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
-
 	for (cpu = 0; cpu < nr_cpus; cpu++) {
 		free(saved_cpu_idle_disable_state[cpu]);
 		saved_cpu_idle_disable_state[cpu] = NULL;
-- 
2.52.0