On Mon, Feb 09, 2026 at 11:24:33AM +0200, Costa Shulyupin wrote: > 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.
Isn't it necessary for C23 compilers? > > Signed-off-by: Costa Shulyupin <[email protected]> > --- > 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, ¶ms->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, ¶ms->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 > <[email protected]> > */ > 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 >
