[PATCH v4 5/6] rtla/timerlat: Add --deepest-idle-state for hist

From: tglozar
Date: Tue Oct 15 2024 - 09:37:14 EST


From: Tomas Glozar <tglozar@xxxxxxxxxx>

Support limiting deepest idle state also for timerlat-hist.

Signed-off-by: Tomas Glozar <tglozar@xxxxxxxxxx>
---
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);
}
--
2.47.0