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Message-ID: <20251205151924.2250142-1-costa.shul@redhat.com>
Date: Fri, 5 Dec 2025 17:19:21 +0200
From: Costa Shulyupin <costa.shul@...hat.com>
To: Steven Rostedt <rostedt@...dmis.org>,
Tomas Glozar <tglozar@...hat.com>,
Crystal Wood <crwood@...hat.com>,
Wander Lairson Costa <wander@...hat.com>,
Costa Shulyupin <costa.shul@...hat.com>,
Ivan Pravdin <ipravdin.official@...il.com>,
John Kacur <jkacur@...hat.com>,
Tiezhu Yang <yangtiezhu@...ngson.cn>,
linux-trace-kernel@...r.kernel.org,
linux-kernel@...r.kernel.org,
bpf@...r.kernel.org
Subject: [PATCH v1 1/4] tools/rtla: Consolidate nr_cpus usage across all tools
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.
Signed-off-by: Costa Shulyupin <costa.shul@...hat.com>
---
tools/tracing/rtla/src/common.c | 6 ++++--
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/utils.c | 10 +---------
10 files changed, 9 insertions(+), 38 deletions(-)
diff --git a/tools/tracing/rtla/src/common.c b/tools/tracing/rtla/src/common.c
index b197037fc58b..38ee2ad21e65 100644
--- a/tools/tracing/rtla/src/common.c
+++ b/tools/tracing/rtla/src/common.c
@@ -4,11 +4,12 @@
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
-#include <unistd.h>
+#include <sys/sysinfo.h>
#include "common.h"
struct trace_instance *trace_inst;
int stop_tracing;
+int nr_cpus;
static void stop_trace(int sig)
{
@@ -55,7 +56,7 @@ 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, ¶ms->monitored_cpus);
}
@@ -103,6 +104,7 @@ 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 9ec2b7632c37..2765e2a9f85f 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 ff8c231e47c4..0bed9717cef6 100644
--- a/tools/tracing/rtla/src/osnoise_hist.c
+++ b/tools/tracing/rtla/src/osnoise_hist.c
@@ -699,9 +699,6 @@ 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 04c699bdd736..8fa0046f0136 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);
@@ -547,9 +543,6 @@ 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 df4f9bfe3433..7503e18b905c 100644
--- a/tools/tracing/rtla/src/timerlat.c
+++ b/tools/tracing/rtla/src/timerlat.c
@@ -108,7 +108,7 @@ 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);
@@ -124,8 +124,6 @@ int timerlat_enable(struct osnoise_tool *tool)
return -1;
}
- nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
-
for_each_monitored_cpu(i, nr_cpus, ¶ms->common) {
if (save_cpu_idle_disable_state(i) < 0) {
err_msg("Could not save cpu idle state.\n");
@@ -213,7 +211,6 @@ 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 1fb471a787b7..37bb9b931c8c 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -1077,9 +1077,6 @@ 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 29c2c1f717ed..8b15f4439c6c 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -443,15 +443,11 @@ 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);
@@ -827,9 +823,6 @@ 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/utils.c b/tools/tracing/rtla/src/utils.c
index 9cf5a0098e9a..afb32d2431c3 100644
--- a/tools/tracing/rtla/src/utils.c
+++ b/tools/tracing/rtla/src/utils.c
@@ -18,7 +18,7 @@
#include <sched.h>
#include <stdio.h>
-#include "utils.h"
+#include "common.h"
#define MAX_MSG_LENGTH 1024
int config_debug;
@@ -118,14 +118,11 @@ 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)
@@ -552,7 +549,6 @@ 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);
@@ -560,7 +556,6 @@ 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;
@@ -637,13 +632,10 @@ 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
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