From: Tomas Glozar <tglozar@redhat.com>
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.
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
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 9ac71a66840c..6ae084fdedf9 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;
+
+ if (!saved_cpu_idle_disable_state)
+ return -1;
+
+ nr_states = cpuidle_state_count(cpu);
+
+ if (nr_states == 0)
+ return 0;
+
+ 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 d44513e6c66a..e439db7fc848 100644
--- a/tools/tracing/rtla/src/utils.h
+++ b/tools/tracing/rtla/src/utils.h
@@ -64,6 +64,19 @@ 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))
--
2.46.2On Fri, 4 Oct 2024 11:50:11 +0200
tglozar@redhat.com wrote:
> From: Tomas Glozar <tglozar@redhat.com>
>
> 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.
>
> Signed-off-by: Tomas Glozar <tglozar@redhat.com>
> ---
> 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 9ac71a66840c..6ae084fdedf9 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 nr_states is zero, this returns 0 without ever allocating
saved_cpu_idle_disable_state.
> +
> + 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;
> +
> + if (!saved_cpu_idle_disable_state)
> + return -1;
This returns -1 even if nr_states is zero. That is,
save_cpu_idle_disable_state() can return success, but this restore will
return failure.
-- Steve
> +
> + nr_states = cpuidle_state_count(cpu);
> +
> + if (nr_states == 0)
> + return 0;
> +
> + 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 d44513e6c66a..e439db7fc848 100644
> --- a/tools/tracing/rtla/src/utils.h
> +++ b/tools/tracing/rtla/src/utils.h
> @@ -64,6 +64,19 @@ 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))
čt 10. 10. 2024 v 22:06 odesílatel Steven Rostedt <rostedt@goodmis.org> napsal: > > If nr_states is zero, this returns 0 without ever allocating > saved_cpu_idle_disable_state. > >> ... > > This returns -1 even if nr_states is zero. That is, > save_cpu_idle_disable_state() can return success, but this restore will > return failure. > > -- Steve Oh I see: there might be no idle states to save, saved_cpu_idle_disable_state doesn't get allocated at all, and then restore_cpu_idle_disable_state behaves as the saves weren't saved before. Checking for nr_state should fix that; I'll send a v3. Tomas
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