@@ -753,6 +753,15 @@ osnoise_hist_apply_config(struct osnoise_tool *tool, struct osnoise_hist_params
err_msg("Failed to set rtla to the house keeping CPUs\n");
goto out_err;
}
+ } else if (params->cpus) {
+ /*
+ * Even if the user do not set a house-keeping CPU, try to
+ * move rtla to a CPU set different to the one where the user
+ * set the workload to run.
+ *
+ * No need to check results as this is an automatic attempt.
+ */
+ auto_house_keeping(¶ms->monitored_cpus);
}
return 0;
@@ -582,6 +582,15 @@ osnoise_top_apply_config(struct osnoise_tool *tool, struct osnoise_top_params *p
err_msg("Failed to set rtla to the house keeping CPUs\n");
goto out_err;
}
+ } else if (params->cpus) {
+ /*
+ * Even if the user do not set a house-keeping CPU, try to
+ * move rtla to a CPU set different to the one where the user
+ * set the workload to run.
+ *
+ * No need to check results as this is an automatic attempt.
+ */
+ auto_house_keeping(¶ms->monitored_cpus);
}
return 0;
@@ -776,6 +776,15 @@ timerlat_hist_apply_config(struct osnoise_tool *tool, struct timerlat_hist_param
err_msg("Failed to set rtla to the house keeping CPUs\n");
goto out_err;
}
+ } else if (params->cpus) {
+ /*
+ * Even if the user do not set a house-keeping CPU, try to
+ * move rtla to a CPU set different to the one where the user
+ * set the workload to run.
+ *
+ * No need to check results as this is an automatic attempt.
+ */
+ auto_house_keeping(¶ms->monitored_cpus);
}
return 0;
@@ -619,6 +619,15 @@ timerlat_top_apply_config(struct osnoise_tool *top, struct timerlat_top_params *
err_msg("Failed to set rtla to the house keeping CPUs\n");
goto out_err;
}
+ } else if (params->cpus) {
+ /*
+ * Even if the user do not set a house-keeping CPU, try to
+ * move rtla to a CPU set different to the one where the user
+ * set the workload to run.
+ *
+ * No need to check results as this is an automatic attempt.
+ */
+ auto_house_keeping(¶ms->monitored_cpus);
}
return 0;
@@ -709,3 +709,53 @@ int set_comm_cgroup(const char *comm_prefix, const char *cgroup)
close(cg_fd);
return 0;
}
+
+/**
+ * auto_house_keeping - Automatically move rtla out of measurement threads
+ *
+ * Try to move rtla away from the tracer, if possible.
+ *
+ * Returns 1 on success, 0 otherwise.
+ */
+int auto_house_keeping(cpu_set_t *monitored_cpus)
+{
+ cpu_set_t rtla_cpus, house_keeping_cpus;
+ int retval;
+
+ /* first get the CPUs in which rtla can actually run. */
+ retval = sched_getaffinity(getpid(), sizeof(rtla_cpus), &rtla_cpus);
+ if (retval == -1) {
+ debug_msg("Could not get rtla affinity, rtla might run with the threads!\n");
+ return 0;
+ }
+
+ /* then check if the existing setup is already good. */
+ CPU_AND(&house_keeping_cpus, &rtla_cpus, monitored_cpus);
+ if (!CPU_COUNT(&house_keeping_cpus)) {
+ debug_msg("rtla and the monitored CPUs do not share CPUs.");
+ debug_msg("Skipping auto house-keeping\n");
+ return 1;
+ }
+
+ /* remove the intersection */
+ CPU_XOR(&house_keeping_cpus, &rtla_cpus, monitored_cpus);
+
+ /* get only those that rtla can run */
+ CPU_AND(&house_keeping_cpus, &house_keeping_cpus, &rtla_cpus);
+
+ /* is there any cpu left? */
+ if (!CPU_COUNT(&house_keeping_cpus)) {
+ debug_msg("Could not find any CPU for auto house-keeping\n");
+ return 0;
+ }
+
+ retval = sched_setaffinity(getpid(), sizeof(house_keeping_cpus), &house_keeping_cpus);
+ if (retval == -1) {
+ debug_msg("Could not set affinity for auto house-keeping\n");
+ return 0;
+ }
+
+ debug_msg("rtla automatically moved to an auto house-keeping cpu set\n");
+
+ return 1;
+}
@@ -60,6 +60,7 @@ int parse_cpu_set(char *cpu_list, cpu_set_t *set);
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_cpu_dma_latency(int32_t latency);
+int auto_house_keeping(cpu_set_t *monitored_cpus);
#define ns_to_usf(x) (((double)x/1000))
#define ns_to_per(total, part) ((part * 100) / (double)total)
When the user sets -c <cpu-list> try to move rtla out of the <cpu-list>, even without an -H option. This is useful to avoid having rtla interfering with the workload. This works by removing <cpu-list> from rtla's current affinity. If rtla fails to move itself away it is not that of a problem as this is an automatic measure. Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> --- tools/tracing/rtla/src/osnoise_hist.c | 9 +++++ tools/tracing/rtla/src/osnoise_top.c | 9 +++++ tools/tracing/rtla/src/timerlat_hist.c | 9 +++++ tools/tracing/rtla/src/timerlat_top.c | 9 +++++ tools/tracing/rtla/src/utils.c | 50 ++++++++++++++++++++++++++ tools/tracing/rtla/src/utils.h | 1 + 6 files changed, 87 insertions(+)