| Message ID | 20240731083655.375293-4-tglozar@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | rtla: Support idle state disabling via libcpupower in timerlat | expand |
On Wed, 31 Jul 2024 10:36:52 +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 | 140 +++++++++++++++++++++++++++++++++ > tools/tracing/rtla/src/utils.h | 6 ++ > 2 files changed, 146 insertions(+) > > diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c > index 9ac71a66840c..9279b8ce08c3 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 +522,143 @@ 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 *)); Need to check if the calloc failed and return an error if it did. > + } > + > + saved_cpu_idle_disable_state[cpu] = calloc(nr_states, sizeof(unsigned int)); Here too. > + 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; Hmm, should this warn if state is not zero and disabled is negative. > + 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; > + Should probably have a check to see if saved_cpu_idle_disable exists. > + nr_states = cpuidle_state_count(cpu); > + > + if (nr_states == 0) > + return 0; > + As well as saved_cpu_idle_disable_state[cpu] exists. Just for robustness. > + for (state = 0; state < nr_states; state++) { > + 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; > + > + if (!saved_cpu_idle_disable_state) > + return; > + > + for (cpu = 0; cpu < sysconf(_SC_NPROCESSORS_CONF); cpu++) { > + if (!saved_cpu_idle_disable_state[cpu]) > + continue; No need to check here. free() works fine with passing NULL to it. -- Steve > + 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..51b6054c2679 100644 > --- a/tools/tracing/rtla/src/utils.h > +++ b/tools/tracing/rtla/src/utils.h > @@ -64,6 +64,12 @@ 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); > +#endif /* HAVE_LIBCPUPOWER_SUPPORT */ > int auto_house_keeping(cpu_set_t *monitored_cpus); > > #define ns_to_usf(x) (((double)x/1000))
> > Need to check if the calloc failed and return an error if it did. > Definitely, I completely missed that. > > Hmm, should this warn if state is not zero and disabled is negative. > rtla timerlat hist/top will error out if save_cpu_idle_disable_state returns a negative value, so I don't think a warning is necessary here. ``` if (save_cpu_idle_disable_state(i) < 0) { err_msg("Could not save cpu idle state.\n"); goto out_free; } ``` > > Should probably have a check to see if saved_cpu_idle_disable exists. > > > + nr_states = cpuidle_state_count(cpu); > > + > > + if (nr_states == 0) > > + return 0; > > + > > As well as saved_cpu_idle_disable_state[cpu] exists. > > Just for robustness. > Right, that would help catch some possible bugs if restore_cpu_idle_disable_state is ever called before save_cpu_idle_disable_state. The values of saved_cpu_idle_disable_state and saved_cpu_idle_disable_state[cpu] have to be read anyway, checking for zero should not make any noticeable difference. > > No need to check here. free() works fine with passing NULL to it. > Ah, I see, I need to check that for saved_cpu_idle_disable_state so that I won't be accessing null memory in the for loop, but not for saved_cpu_idle_disable_state[cpu], where I just call free(). Tomas
diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c index 9ac71a66840c..9279b8ce08c3 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 +522,143 @@ 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 *)); + } + + saved_cpu_idle_disable_state[cpu] = calloc(nr_states, sizeof(unsigned int)); + 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; + + for (state = 0; state < nr_states; state++) { + 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; + + if (!saved_cpu_idle_disable_state) + return; + + for (cpu = 0; cpu < sysconf(_SC_NPROCESSORS_CONF); cpu++) { + if (!saved_cpu_idle_disable_state[cpu]) + continue; + 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..51b6054c2679 100644 --- a/tools/tracing/rtla/src/utils.h +++ b/tools/tracing/rtla/src/utils.h @@ -64,6 +64,12 @@ 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); +#endif /* HAVE_LIBCPUPOWER_SUPPORT */ int auto_house_keeping(cpu_set_t *monitored_cpus); #define ns_to_usf(x) (((double)x/1000))