Kernels pre v6.6 won't have:
39f7c41c908b ("tracing/filters: Enable filtering a cpumask field by another
cpumask")
and thus won't be able to filter events using a user-provided cpumask, but
will still be capable of recording IPI events.
Make failing to set a filter for IPI events an acceptable error and fall
back to event handlers that do the filtering job themselves.
Suggested-by: Tomas Glozar <[email protected]>
Signed-off-by: Valentin Schneider <[email protected]>
---
tools/tracing/rtla/src/osnoise_top.c | 49 +++++++++++++++++++++++++---
1 file changed, 45 insertions(+), 4 deletions(-)
diff --git a/tools/tracing/rtla/src/osnoise_top.c
b/tools/tracing/rtla/src/osnoise_top.c
index 353b435fefcf8..afab2f341a1e9 100644
--- a/tools/tracing/rtla/src/osnoise_top.c
+++ b/tools/tracing/rtla/src/osnoise_top.c
@@ -313,6 +313,30 @@ osnoise_ipi_cpu_handler(struct trace_seq *s, struct
tep_record *record,
return 0;
}
+/*
+ * osnoise_ipi_cpu_unfiltered_handler - this is the handler for single CPU IPI
+ * events. Slightly less optimized than
+ * the filtered variant.
+ */
+static int
+osnoise_ipi_cpu_unfiltered_handler(struct trace_seq *s, struct tep_record
*record,
+ struct tep_event *event, void *context)
+{
+ struct osnoise_tool *tool;
+ unsigned long long dst_cpu;
+ struct osnoise_params *params;
+ struct trace_instance *trace = context;
+
+ tool = container_of(trace, struct osnoise_tool, trace);
+ params = to_osnoise_params(tool->params);
+ tep_get_field_val(s, event, "cpu", record, &dst_cpu, 1);
+
+ if (CPU_ISSET(dst_cpu, ¶ms->common.monitored_cpus))
+ account_ipi(tool, dst_cpu);
+
+ return 0;
+}
+
static cpu_set_t cpumask_tmp_cpus;
/*
@@ -343,7 +367,7 @@ osnoise_ipi_cpumask_handler(struct trace_seq *s, struct
tep_record *record,
}
/*
- * Despite already filtering for such an intersection, we need to
compute
+ * Even if already filtering for such an intersection, we need to
compute
* the intersection here as the @cpumask field may contain non-monitored
* CPUs.
*/
@@ -368,6 +392,7 @@ osnoise_ipi_cpumask_handler(struct trace_seq *s, struct
tep_record *record,
*/
struct osnoise_tool *osnoise_init_top(struct common_params *params)
{
+ bool ipi_filters_enabled = false;
struct osnoise_tool *tool;
int retval;
@@ -402,6 +427,8 @@ struct osnoise_tool *osnoise_init_top(struct common_params
*params)
/*
* If tracing on a subset of possible CPUs, leverage the kernel
filtering
* infrastructure to only generate events on traced CPUs.
+ * Older kernels (pre v6.6) may have the IPI events but not the ability
+ * to filter them, so allow that to fail gracefully.
*/
if (params->cpus) {
char filter[MAX_PATH];
@@ -411,8 +438,8 @@ struct osnoise_tool *osnoise_init_top(struct common_params
*params)
"ipi", "ipi_send_cpu",
"filter",
filter);
if (retval < 0) {
- err_msg("Could not set ipi_send_cpu CPU filter\n");
- goto out_err;
+ debug_msg("Could not set ipi_send_cpu CPU filter\n");
+ goto no_filter;
}
@@ -421,13 +448,27 @@ struct osnoise_tool *osnoise_init_top(struct
common_params *params)
"ipi", "ipi_send_cpumask",
"filter",
filter);
if (retval < 0) {
+ /*
+ * If we managed to set up the previous filter but not
+ * this one, something's really wrong
+ */
err_msg("Could not set ipi_send_cpumask CPU filter\n");
goto out_err;
}
+
+ ipi_filters_enabled = true;
}
+no_filter:
+ /*
+ * If no filtering is available and we're tracing all CPUs, we can still
+ * use the filtered callback since stats are collected for all CPUs.
+ */
tep_register_event_handler(tool->trace.tep, -1, "ipi", "ipi_send_cpu",
- osnoise_ipi_cpu_handler, NULL);
+ (!params->cpus || ipi_filters_enabled) ?
+ osnoise_ipi_cpu_handler :
+ osnoise_ipi_cpu_unfiltered_handler,
+ NULL);
tep_register_event_handler(tool->trace.tep, -1, "ipi",
"ipi_send_cpumask",
osnoise_ipi_cpumask_handler, NULL);
--
2.55.0
