[for-next][PATCH 0/6] rtla: Updates for 6.13

[for-next][PATCH 0/6] rtla: Updates for 6.13

[Steven Rostedt]

  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
tools/for-next

Head SHA1: 13216486e3ede30d6910a22e0e15988b7016366b


Tomas Glozar (6):
      tools/build: Add libcpupower dependency detection
      rtla: Add optional dependency on libcpupower
      rtla/utils: Add idle state disabling via libcpupower
      rtla/timerlat: Add --deepest-idle-state for top
      rtla/timerlat: Add --deepest-idle-state for hist
      rtla: Documentation: Mention --deepest-idle-state

----
 .../tools/rtla/common_timerlat_options.rst         |   8 ++
 tools/build/Makefile.feature                       |   1 +
 tools/build/feature/Makefile                       |   4 +
 tools/build/feature/test-libcpupower.c             |   8 ++
 tools/tracing/rtla/Makefile                        |   2 +
 tools/tracing/rtla/Makefile.config                 |  10 ++
 tools/tracing/rtla/README.txt                      |   4 +
 tools/tracing/rtla/src/timerlat_hist.c             |  42 +++++-
 tools/tracing/rtla/src/timerlat_top.c              |  42 +++++-
 tools/tracing/rtla/src/utils.c                     | 150 +++++++++++++++++++++
 tools/tracing/rtla/src/utils.h                     |  13 ++
 11 files changed, 282 insertions(+), 2 deletions(-)
 create mode 100644 tools/build/feature/test-libcpupower.c

[for-next][PATCH 1/6] tools/build: Add libcpupower dependency detection

[Steven Rostedt]

From: Tomas Glozar <tglozar@redhat.com>

Add the ability to detect the presence of libcpupower on a system to
the Makefiles in tools/build.

Link: https://lore.kernel.org/20241017140914.3200454-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 tools/build/Makefile.feature           | 1 +
 tools/build/feature/Makefile           | 4 ++++
 tools/build/feature/test-libcpupower.c | 8 ++++++++
 3 files changed, 13 insertions(+)
 create mode 100644 tools/build/feature/test-libcpupower.c

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index ffd117135094..2ebfb826dcea 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -53,6 +53,7 @@ FEATURE_TESTS_BASIC :=                  \
         libslang-include-subdir         \
         libtraceevent                   \
         libtracefs                      \
+        libcpupower                     \
         libcrypto                       \
         libunwind                       \
         pthread-attr-setaffinity-np     \
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 5938cf799dc6..6ef3e1ca583e 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -38,6 +38,7 @@ FILES=                                          \
          test-libslang.bin                      \
          test-libslang-include-subdir.bin       \
          test-libtraceevent.bin                 \
+         test-libcpupower.bin                   \
          test-libtracefs.bin                    \
          test-libcrypto.bin                     \
          test-libunwind.bin                     \
@@ -245,6 +246,9 @@ $(OUTPUT)test-libslang-include-subdir.bin:
 $(OUTPUT)test-libtraceevent.bin:
 	$(BUILD) -ltraceevent
 
+$(OUTPUT)test-libcpupower.bin:
+	$(BUILD) -lcpupower
+
 $(OUTPUT)test-libtracefs.bin:
 	 $(BUILD) $(shell $(PKG_CONFIG) --cflags libtracefs 2>/dev/null) -ltracefs
 
diff --git a/tools/build/feature/test-libcpupower.c b/tools/build/feature/test-libcpupower.c
new file mode 100644
index 000000000000..a346aa332a71
--- /dev/null
+++ b/tools/build/feature/test-libcpupower.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <cpuidle.h>
+
+int main(void)
+{
+	int rv = cpuidle_state_count(0);
+	return rv;
+}
-- 
2.45.2

[for-next][PATCH 2/6] rtla: Add optional dependency on libcpupower

[Steven Rostedt]

From: Tomas Glozar <tglozar@redhat.com>

If libcpupower is present, set HAVE_LIBCPUPOWER_SUPPORT macro to allow
features depending on libcpupower in rtla.

Link: https://lore.kernel.org/20241017140914.3200454-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 tools/tracing/rtla/Makefile        |  2 ++
 tools/tracing/rtla/Makefile.config | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/tools/tracing/rtla/Makefile b/tools/tracing/rtla/Makefile
index b5878be36125..a6a7dee16622 100644
--- a/tools/tracing/rtla/Makefile
+++ b/tools/tracing/rtla/Makefile
@@ -32,8 +32,10 @@ DOCSRC		:= ../../../Documentation/tools/rtla/
 
 FEATURE_TESTS	:= libtraceevent
 FEATURE_TESTS	+= libtracefs
+FEATURE_TESTS	+= libcpupower
 FEATURE_DISPLAY	:= libtraceevent
 FEATURE_DISPLAY	+= libtracefs
+FEATURE_DISPLAY	+= libcpupower
 
 ifeq ($(V),1)
   Q		=
diff --git a/tools/tracing/rtla/Makefile.config b/tools/tracing/rtla/Makefile.config
index 5f8c286712d4..92a6e12e42d3 100644
--- a/tools/tracing/rtla/Makefile.config
+++ b/tools/tracing/rtla/Makefile.config
@@ -43,6 +43,16 @@ else
   $(info libtracefs is missing. Please install libtracefs-dev/libtracefs-devel)
 endif
 
+$(call feature_check,libcpupower)
+ifeq ($(feature-libcpupower), 1)
+  $(call detected,CONFIG_LIBCPUPOWER)
+  CFLAGS += -DHAVE_LIBCPUPOWER_SUPPORT
+  EXTLIBS += -lcpupower
+else
+  $(info libcpupower is missing, building without --deepest-idle-state support.)
+  $(info Please install libcpupower-dev/kernel-tools-libs-devel)
+endif
+
 ifeq ($(STOP_ERROR),1)
   $(error Please, check the errors above.)
 endif
-- 
2.45.2

[for-next][PATCH 3/6] rtla/utils: Add idle state disabling via libcpupower

[Steven Rostedt]

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.

Link: https://lore.kernel.org/20241017140914.3200454-4-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 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 6fae234aaf36..4995d35cf3ec 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>
@@ -515,6 +518,153 @@ 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 99c9cf81bcd0..101d4799a009 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))
-- 
2.45.2

[for-next][PATCH 4/6] rtla/timerlat: Add --deepest-idle-state for top

[Steven Rostedt]

From: Tomas Glozar <tglozar@redhat.com>

Add option to limit deepest idle state on CPUs where timerlat is running
for the duration of the workload.

Link: https://lore.kernel.org/20241017140914.3200454-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 tools/tracing/rtla/src/timerlat_top.c | 42 ++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 7fb85c8ee3bc..fca0da3caa87 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -48,6 +48,7 @@ struct timerlat_top_params {
 	int			pretty_output;
 	int			warmup;
 	int			buffer_size;
+	int			deepest_idle_state;
 	cpu_set_t		hk_cpu_set;
 	struct sched_attr	sched_param;
 	struct trace_events	*events;
@@ -447,7 +448,7 @@ static void timerlat_top_usage(char *usage)
 		"",
 		"  usage: rtla timerlat [top] [-h] [-q] [-a us] [-d s] [-D] [-n] [-p us] [-i us] [-T us] [-s us] \\",
 		"	  [[-t[file]] [-e sys[:event]] [--filter <filter>] [--trigger <trigger>] [-c cpu-list] [-H cpu-list]\\",
-		"	  [-P priority] [--dma-latency us] [--aa-only us] [-C[=cgroup_name]] [-u|-k] [--warm-up s]",
+		"	  [-P priority] [--dma-latency us] [--aa-only us] [-C[=cgroup_name]] [-u|-k] [--warm-up s] [--deepest-idle-state n]",
 		"",
 		"	  -h/--help: print this menu",
 		"	  -a/--auto: set automatic trace mode, stopping the session if argument in us latency is hit",
@@ -481,6 +482,7 @@ static void timerlat_top_usage(char *usage)
 		"	  -U/--user-load: enable timerlat for user-defined user-space workload",
 		"	     --warm-up s: let the workload run for s seconds before collecting data",
 		"	     --trace-buffer-size kB: set the per-cpu trace buffer size in kB",
+		"	     --deepest-idle-state n: only go down to idle state n on cpus used by timerlat to reduce exit from idle latency",
 		NULL,
 	};
 
@@ -518,6 +520,9 @@ static struct timerlat_top_params
 	/* disabled by default */
 	params->dma_latency = -1;
 
+	/* disabled by default */
+	params->deepest_idle_state = -2;
+
 	/* display data in microseconds */
 	params->output_divisor = 1000;
 
@@ -550,6 +555,7 @@ static struct timerlat_top_params
 			{"aa-only",		required_argument,	0, '5'},
 			{"warm-up",		required_argument,	0, '6'},
 			{"trace-buffer-size",	required_argument,	0, '7'},
+			{"deepest-idle-state",	required_argument,	0, '8'},
 			{0, 0, 0, 0}
 		};
 
@@ -726,6 +732,9 @@ static struct timerlat_top_params
 		case '7':
 			params->buffer_size = get_llong_from_str(optarg);
 			break;
+		case '8':
+			params->deepest_idle_state = get_llong_from_str(optarg);
+			break;
 		default:
 			timerlat_top_usage("Invalid option");
 		}
@@ -922,6 +931,7 @@ int timerlat_top_main(int argc, char *argv[])
 	int return_value = 1;
 	char *max_lat;
 	int retval;
+	int nr_cpus, i;
 
 	params = timerlat_top_parse_args(argc, argv);
 	if (!params)
@@ -971,6 +981,28 @@ int timerlat_top_main(int argc, char *argv[])
 		}
 	}
 
+	if (params->deepest_idle_state >= -1) {
+		if (!have_libcpupower_support()) {
+			err_msg("rtla built without libcpupower, --deepest-idle-state is not supported\n");
+			goto out_free;
+		}
+
+		nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+
+		for (i = 0; i < nr_cpus; i++) {
+			if (params->cpus && !CPU_ISSET(i, &params->monitored_cpus))
+				continue;
+			if (save_cpu_idle_disable_state(i) < 0) {
+				err_msg("Could not save cpu idle state.\n");
+				goto out_free;
+			}
+			if (set_deepest_cpu_idle_state(i, params->deepest_idle_state) < 0) {
+				err_msg("Could not set deepest cpu idle state.\n");
+				goto out_free;
+			}
+		}
+	}
+
 	if (params->trace_output) {
 		record = osnoise_init_trace_tool("timerlat");
 		if (!record) {
@@ -1125,6 +1157,13 @@ int timerlat_top_main(int argc, char *argv[])
 	timerlat_aa_destroy();
 	if (dma_latency_fd >= 0)
 		close(dma_latency_fd);
+	if (params->deepest_idle_state >= -1) {
+		for (i = 0; i < nr_cpus; i++) {
+			if (params->cpus && !CPU_ISSET(i, &params->monitored_cpus))
+				continue;
+			restore_cpu_idle_disable_state(i);
+		}
+	}
 	trace_events_destroy(&record->trace, params->events);
 	params->events = NULL;
 out_free:
@@ -1134,6 +1173,7 @@ int timerlat_top_main(int argc, char *argv[])
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(top);
 	free(params);
+	free_cpu_idle_disable_states();
 out_exit:
 	exit(return_value);
 }
-- 
2.45.2

[for-next][PATCH 5/6] rtla/timerlat: Add --deepest-idle-state for hist

[Steven Rostedt]

From: Tomas Glozar <tglozar@redhat.com>

Support limiting deepest idle state also for timerlat-hist.

Link: https://lore.kernel.org/20241017140914.3200454-6-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 tools/tracing/rtla/src/timerlat_hist.c | 42 +++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index d49c8f0855fe..01dd337da13a 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -55,6 +55,7 @@ struct timerlat_hist_params {
 	int			entries;
 	int			warmup;
 	int			buffer_size;
+	int			deepest_idle_state;
 };
 
 struct timerlat_hist_cpu {
@@ -655,7 +656,7 @@ static void timerlat_hist_usage(char *usage)
 		"         [-t[file]] [-e sys[:event]] [--filter <filter>] [--trigger <trigger>] [-c cpu-list] [-H cpu-list]\\",
 		"	  [-P priority] [-E N] [-b N] [--no-irq] [--no-thread] [--no-header] [--no-summary] \\",
 		"	  [--no-index] [--with-zeros] [--dma-latency us] [-C[=cgroup_name]] [--no-aa] [--dump-task] [-u|-k]",
-		"	  [--warm-up s]",
+		"	  [--warm-up s] [--deepest-idle-state n]",
 		"",
 		"	  -h/--help: print this menu",
 		"	  -a/--auto: set automatic trace mode, stopping the session if argument in us latency is hit",
@@ -695,6 +696,7 @@ static void timerlat_hist_usage(char *usage)
 		"	  -U/--user-load: enable timerlat for user-defined user-space workload",
 		"	     --warm-up s: let the workload run for s seconds before collecting data",
 		"	     --trace-buffer-size kB: set the per-cpu trace buffer size in kB",
+		"	     --deepest-idle-state n: only go down to idle state n on cpus used by timerlat to reduce exit from idle latency",
 		NULL,
 	};
 
@@ -732,6 +734,9 @@ static struct timerlat_hist_params
 	/* disabled by default */
 	params->dma_latency = -1;
 
+	/* disabled by default */
+	params->deepest_idle_state = -2;
+
 	/* display data in microseconds */
 	params->output_divisor = 1000;
 	params->bucket_size = 1;
@@ -772,6 +777,7 @@ static struct timerlat_hist_params
 			{"dump-task",		no_argument,		0, '\1'},
 			{"warm-up",		required_argument,	0, '\2'},
 			{"trace-buffer-size",	required_argument,	0, '\3'},
+			{"deepest-idle-state",	required_argument,	0, '\4'},
 			{0, 0, 0, 0}
 		};
 
@@ -960,6 +966,9 @@ static struct timerlat_hist_params
 		case '\3':
 			params->buffer_size = get_llong_from_str(optarg);
 			break;
+		case '\4':
+			params->deepest_idle_state = get_llong_from_str(optarg);
+			break;
 		default:
 			timerlat_hist_usage("Invalid option");
 		}
@@ -1152,6 +1161,7 @@ int timerlat_hist_main(int argc, char *argv[])
 	int return_value = 1;
 	pthread_t timerlat_u;
 	int retval;
+	int nr_cpus, i;
 
 	params = timerlat_hist_parse_args(argc, argv);
 	if (!params)
@@ -1201,6 +1211,28 @@ int timerlat_hist_main(int argc, char *argv[])
 		}
 	}
 
+	if (params->deepest_idle_state >= -1) {
+		if (!have_libcpupower_support()) {
+			err_msg("rtla built without libcpupower, --deepest-idle-state is not supported\n");
+			goto out_free;
+		}
+
+		nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+
+		for (i = 0; i < nr_cpus; i++) {
+			if (params->cpus && !CPU_ISSET(i, &params->monitored_cpus))
+				continue;
+			if (save_cpu_idle_disable_state(i) < 0) {
+				err_msg("Could not save cpu idle state.\n");
+				goto out_free;
+			}
+			if (set_deepest_cpu_idle_state(i, params->deepest_idle_state) < 0) {
+				err_msg("Could not set deepest cpu idle state.\n");
+				goto out_free;
+			}
+		}
+	}
+
 	if (params->trace_output) {
 		record = osnoise_init_trace_tool("timerlat");
 		if (!record) {
@@ -1332,6 +1364,13 @@ int timerlat_hist_main(int argc, char *argv[])
 	timerlat_aa_destroy();
 	if (dma_latency_fd >= 0)
 		close(dma_latency_fd);
+	if (params->deepest_idle_state >= -1) {
+		for (i = 0; i < nr_cpus; i++) {
+			if (params->cpus && !CPU_ISSET(i, &params->monitored_cpus))
+				continue;
+			restore_cpu_idle_disable_state(i);
+		}
+	}
 	trace_events_destroy(&record->trace, params->events);
 	params->events = NULL;
 out_free:
@@ -1340,6 +1379,7 @@ int timerlat_hist_main(int argc, char *argv[])
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(tool);
 	free(params);
+	free_cpu_idle_disable_states();
 out_exit:
 	exit(return_value);
 }
-- 
2.45.2

[for-next][PATCH 6/6] rtla: Documentation: Mention --deepest-idle-state

[Steven Rostedt]

From: Tomas Glozar <tglozar@redhat.com>

Add --deepest-idle-state to manpage and mention libcpupower dependency
in README.txt.

Link: https://lore.kernel.org/20241017140914.3200454-7-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 Documentation/tools/rtla/common_timerlat_options.rst | 8 ++++++++
 tools/tracing/rtla/README.txt                        | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/Documentation/tools/rtla/common_timerlat_options.rst b/Documentation/tools/rtla/common_timerlat_options.rst
index cef6651f1435..10dc802f8d65 100644
--- a/Documentation/tools/rtla/common_timerlat_options.rst
+++ b/Documentation/tools/rtla/common_timerlat_options.rst
@@ -31,6 +31,14 @@
         *cyclictest* sets this value to *0* by default, use **--dma-latency** *0* to have
         similar results.
 
+**--deepest-idle-state** *n*
+        Disable idle states higher than *n* for cpus that are running timerlat threads to
+        reduce exit from idle latencies. If *n* is -1, all idle states are disabled.
+        On exit from timerlat, the idle state setting is restored to its original state
+        before running timerlat.
+
+        Requires rtla to be built with libcpupower.
+
 **-k**, **--kernel-threads**
 
         Use timerlat kernel-space threads, in contrast of **-u**.
diff --git a/tools/tracing/rtla/README.txt b/tools/tracing/rtla/README.txt
index 4af3fd40f171..dd5621038c55 100644
--- a/tools/tracing/rtla/README.txt
+++ b/tools/tracing/rtla/README.txt
@@ -11,6 +11,7 @@ RTLA depends on the following libraries and tools:
 
  - libtracefs
  - libtraceevent
+ - libcpupower (optional, for --deepest-idle-state)
 
 It also depends on python3-docutils to compile man pages.
 
@@ -26,6 +27,9 @@ For development, we suggest the following steps for compiling rtla:
   $ make
   $ sudo make install
   $ cd ..
+  $ cd $libcpupower_src
+  $ make
+  $ sudo make install
   $ cd $rtla_src
   $ make
   $ sudo make install
-- 
2.45.2