On Wed, 2 Aug 2023 23:09:54 -0400
Ze Gao <zegao2021@xxxxxxxxx> wrote:
> Update state char array to match the latest kernel
> definitions.
>
> Signed-off-by: Ze Gao <zegao@xxxxxxxxxxx>
> ---
> plugins/plugin_sched_switch.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/plugins/plugin_sched_switch.c b/plugins/plugin_sched_switch.c
> index 8752cae..e0986ac 100644
> --- a/plugins/plugin_sched_switch.c
> +++ b/plugins/plugin_sched_switch.c
> @@ -11,7 +11,7 @@
>
> static void write_state(struct trace_seq *s, int val)
> {
> - const char states[] = "SDTtZXxW";
> + const char states[] = "SDTtXZPI";
> int found = 0;
> int i;
>
Hi Ze,
As your update never made it into the kernel I never pulled these patches
in. But we do have an issue with the state getting out of sync with what
the kernel actually uses.
I did this "hack" but it seems to work. What I do is to look at the
sched_switch event print parsing arguments, find the __print_flags
arguments for the "prev_state" field. And then parse them, creating a new
output and I use that for the write_state() function.
I guess this should work for you too?
I still need to pull in this patch and use that as the default. I'll do
that before applying this one, and have your above update be the default.
Thanks!
-- Steve
diff --git a/plugins/plugin_sched_switch.c b/plugins/plugin_sched_switch.c
index 8752caea5c38..760d224f5507 100644
--- a/plugins/plugin_sched_switch.c
+++ b/plugins/plugin_sched_switch.c
@@ -9,13 +9,132 @@
#include "event-parse.h"
#include "trace-seq.h"
-static void write_state(struct trace_seq *s, int val)
+static const char *convert_sym(struct tep_print_flag_sym *sym)
{
- const char states[] = "SDTtZXxW";
+ static char save_states[33];
+
+ memset(save_states, 0, sizeof(save_states));
+
+ /* This is the flags for the prev_state_field, now make them into a string */
+ for (; sym; sym = sym->next) {
+ long bitmask = strtoul(sym->value, NULL, 0);
+ int i;
+
+ for (i = 0; !(bitmask & 1); i++)
+ bitmask >>= 1;
+
+ if (i > 32)
+ continue; // warn?
+
+ save_states[i] = sym->str[0];
+ }
+
+ return save_states;
+}
+
+static struct tep_print_arg_field *
+find_arg_field(struct tep_format_field *prev_state_field, struct tep_print_arg *arg)
+{
+ struct tep_print_arg_field *field;
+
+ if (!arg)
+ return NULL;
+
+ if (arg->type == TEP_PRINT_FIELD)
+ return &arg->field;
+
+ if (arg->type == TEP_PRINT_OP) {
+ field = find_arg_field(prev_state_field, arg->op.left);
+ if (field && field->field == prev_state_field)
+ return field;
+ field = find_arg_field(prev_state_field, arg->op.right);
+ if (field && field->field == prev_state_field)
+ return field;
+ }
+ return NULL;
+}
+
+static struct tep_print_flag_sym *
+test_flags(struct tep_format_field *prev_state_field, struct tep_print_arg *arg)
+{
+ struct tep_print_arg_field *field;
+
+ field = find_arg_field(prev_state_field, arg->flags.field);
+ if (!field)
+ return NULL;
+
+ return arg->flags.flags;
+}
+
+static struct tep_print_flag_sym *
+search_op(struct tep_format_field *prev_state_field, struct tep_print_arg *arg)
+{
+ struct tep_print_flag_sym *sym = NULL;
+
+ if (!arg)
+ return NULL;
+
+ if (arg->type == TEP_PRINT_OP) {
+ sym = search_op(prev_state_field, arg->op.left);
+ if (sym)
+ return sym;
+
+ sym = search_op(prev_state_field, arg->op.right);
+ if (sym)
+ return sym;
+ } else if (arg->type == TEP_PRINT_FLAGS) {
+ sym = test_flags(prev_state_field, arg);
+ }
+
+ return sym;
+}
+
+static const char *get_states(struct tep_format_field *prev_state_field)
+{
+ struct tep_print_flag_sym *sym;
+ struct tep_print_arg *arg;
+ struct tep_event *event;
+
+ event = prev_state_field->event;
+
+ /*
+ * Look at the event format fields, and search for where
+ * the prev_state is parsed via the format flags.
+ */
+ for (arg = event->print_fmt.args; arg; arg = arg->next) {
+ /*
+ * Currently, the __print_flags() for the prev_state
+ * is embedded in operations, so they too must be
+ * searched.
+ */
+ sym = search_op(prev_state_field, arg);
+ if (sym)
+ return convert_sym(sym);
+ }
+ return NULL;
+}
+
+static void write_state(struct trace_seq *s, struct tep_format_field *field,
+ struct tep_record *record)
+{
+ static struct tep_format_field *prev_state_field;
+ static const char *states;
+ unsigned long long val;
int found = 0;
+ int len;
int i;
- for (i = 0; i < (sizeof(states) - 1); i++) {
+ if (field != prev_state_field) {
+ states = get_states(field);
+ if (!states)
+ states = "SDTtZXxW";
+ prev_state_field = field;
+ }
+
+ tep_read_number_field(field, record->data, &val);
+
+ len = strlen(states);
+ for (i = 0; i < len; i++) {
if (!(val & (1 << i)))
continue;
@@ -99,8 +218,8 @@ static int sched_switch_handler(struct trace_seq *s,
if (tep_get_field_val(s, event, "prev_prio", record, &val, 1) == 0)
trace_seq_printf(s, "[%d] ", (int) val);
- if (tep_get_field_val(s, event, "prev_state", record, &val, 1) == 0)
- write_state(s, val);
+ field = tep_find_any_field(event, "prev_state");
+ write_state(s, field, record);
trace_seq_puts(s, " ==> ");
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