From: Tomas Glozar <tglozar@xxxxxxxxxx> [ Upstream commit 083d29d3784319e9e9fab3ac02683a7b26ae3480 ] Add functions to utils.c to disable idle states through functions of libcpupower. This will serve as the basis for disabling idle states per cpu when running timerlat. Link: https://lore.kernel.org/20241017140914.3200454-4-tglozar@xxxxxxxxxx Signed-off-by: Tomas Glozar <tglozar@xxxxxxxxxx> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/tracing/rtla/src/utils.c | 150 +++++++++++++++++++++++++++++++++ tools/tracing/rtla/src/utils.h | 13 +++ 2 files changed, 163 insertions(+) diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c index 0735fcb827ed7..230f9fc7502dd 100644 --- a/tools/tracing/rtla/src/utils.c +++ b/tools/tracing/rtla/src/utils.c @@ -4,6 +4,9 @@ */ #define _GNU_SOURCE +#ifdef HAVE_LIBCPUPOWER_SUPPORT +#include <cpuidle.h> +#endif /* HAVE_LIBCPUPOWER_SUPPORT */ #include <dirent.h> #include <stdarg.h> #include <stdlib.h> @@ -519,6 +522,153 @@ int set_cpu_dma_latency(int32_t latency) return fd; } +#ifdef HAVE_LIBCPUPOWER_SUPPORT +static unsigned int **saved_cpu_idle_disable_state; +static size_t saved_cpu_idle_disable_state_alloc_ctr; + +/* + * save_cpu_idle_state_disable - save disable for all idle states of a cpu + * + * Saves the current disable of all idle states of a cpu, to be subsequently + * restored via restore_cpu_idle_disable_state. + * + * Return: idle state count on success, negative on error + */ +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); + + if (nr_states == 0) + 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; + } + + saved_cpu_idle_disable_state[cpu] = calloc(nr_states, sizeof(unsigned int)); + if (!saved_cpu_idle_disable_state[cpu]) + return -1; + saved_cpu_idle_disable_state_alloc_ctr++; + + for (state = 0; state < nr_states; state++) { + disabled = cpuidle_is_state_disabled(cpu, state); + if (disabled < 0) + return disabled; + saved_cpu_idle_disable_state[cpu][state] = disabled; + } + + return nr_states; +} + +/* + * restore_cpu_idle_disable_state - restore disable for all idle states of a cpu + * + * Restores the current disable state of all idle states of a cpu that was + * previously saved by save_cpu_idle_disable_state. + * + * Return: idle state count on success, negative on error + */ +int restore_cpu_idle_disable_state(unsigned int cpu) +{ + unsigned int nr_states; + unsigned int state; + int disabled; + int result; + + nr_states = cpuidle_state_count(cpu); + + if (nr_states == 0) + return 0; + + if (!saved_cpu_idle_disable_state) + return -1; + + for (state = 0; state < nr_states; state++) { + if (!saved_cpu_idle_disable_state[cpu]) + return -1; + disabled = saved_cpu_idle_disable_state[cpu][state]; + result = cpuidle_state_disable(cpu, state, disabled); + if (result < 0) + return result; + } + + free(saved_cpu_idle_disable_state[cpu]); + saved_cpu_idle_disable_state[cpu] = NULL; + saved_cpu_idle_disable_state_alloc_ctr--; + if (saved_cpu_idle_disable_state_alloc_ctr == 0) { + free(saved_cpu_idle_disable_state); + saved_cpu_idle_disable_state = NULL; + } + + return nr_states; +} + +/* + * free_cpu_idle_disable_states - free saved idle state disable for all cpus + * + * Frees the memory used for storing cpu idle state disable for all cpus + * and states. + * + * Normally, the memory is freed automatically in + * restore_cpu_idle_disable_state; this is mostly for cleaning up after an + * error. + */ +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; + } + + free(saved_cpu_idle_disable_state); + saved_cpu_idle_disable_state = NULL; +} + +/* + * set_deepest_cpu_idle_state - limit idle state of cpu + * + * Disables all idle states deeper than the one given in + * deepest_state (assuming states with higher number are deeper). + * + * This is used to reduce the exit from idle latency. Unlike + * set_cpu_dma_latency, it can disable idle states per cpu. + * + * Return: idle state count on success, negative on error + */ +int set_deepest_cpu_idle_state(unsigned int cpu, unsigned int deepest_state) +{ + unsigned int nr_states; + unsigned int state; + int result; + + nr_states = cpuidle_state_count(cpu); + + for (state = deepest_state + 1; state < nr_states; state++) { + result = cpuidle_state_disable(cpu, state, 1); + if (result < 0) + return result; + } + + return nr_states; +} +#endif /* HAVE_LIBCPUPOWER_SUPPORT */ + #define _STR(x) #x #define STR(x) _STR(x) diff --git a/tools/tracing/rtla/src/utils.h b/tools/tracing/rtla/src/utils.h index 99c9cf81bcd02..101d4799a0090 100644 --- a/tools/tracing/rtla/src/utils.h +++ b/tools/tracing/rtla/src/utils.h @@ -66,6 +66,19 @@ int set_comm_sched_attr(const char *comm_prefix, struct sched_attr *attr); int set_comm_cgroup(const char *comm_prefix, const char *cgroup); int set_pid_cgroup(pid_t pid, const char *cgroup); int set_cpu_dma_latency(int32_t latency); +#ifdef HAVE_LIBCPUPOWER_SUPPORT +int save_cpu_idle_disable_state(unsigned int cpu); +int restore_cpu_idle_disable_state(unsigned int cpu); +void free_cpu_idle_disable_states(void); +int set_deepest_cpu_idle_state(unsigned int cpu, unsigned int state); +static inline int have_libcpupower_support(void) { return 1; } +#else +static inline int save_cpu_idle_disable_state(unsigned int cpu) { return -1; } +static inline int restore_cpu_idle_disable_state(unsigned int cpu) { return -1; } +static inline void free_cpu_idle_disable_states(void) { } +static inline int set_deepest_cpu_idle_state(unsigned int cpu, unsigned int state) { return -1; } +static inline int have_libcpupower_support(void) { return 0; } +#endif /* HAVE_LIBCPUPOWER_SUPPORT */ int auto_house_keeping(cpu_set_t *monitored_cpus); #define ns_to_usf(x) (((double)x/1000)) -- 2.43.0
