From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
Since it is so common to have in the SQL synthetic event creation logic:
(end.TIMESTAMP_USECS - start.TIMESTAMP_USECS) as delta
for creating latency synthetic events, add a shortcut that does the above.
Now the user only needs to write:
TIMESTAMP_USECS_DELTA as delta
and it will produce the same compare.
Note, TIMESTAMP_DELTA is also equivalent to: (end.TIMESTAMP - start.TIMESTAMP)
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
Documentation/libtracefs-sql.txt | 16 ++++++++
src/tracefs-sqlhist.c | 64 +++++++++++++++++++++++++++++++-
utest/tracefs-utest.c | 10 +++++
3 files changed, 88 insertions(+), 2 deletions(-)
diff --git a/Documentation/libtracefs-sql.txt b/Documentation/libtracefs-sql.txt
index 62fd771b92bb..7921509f3825 100644
--- a/Documentation/libtracefs-sql.txt
+++ b/Documentation/libtracefs-sql.txt
@@ -127,6 +127,22 @@ The *TIMESTAMP_USECS* will truncate the time down to microseconds as the timesta
recorded in the tracing buffer has nanosecond resolution. If you do not want that
truncation, use *TIMESTAMP* instead of *TIMESTAMP_USECS*.
+Because it is so common to have:
+
+[source,c]
+--
+ (end.TIMESTAMP_USECS - start.TIMESTAMP_USECS)
+--
+
+The above can be represented with *TIMESTAMP_USECS_DELTA* or if nanoseconds are OK, you can
+use *TIMESTAMP_DELTA*. That is, the previous select can also be represented by:
+
+[source,c]
+--
+select start.pid, TIMESTAMP_USECS_DELTA as lat from sched_waking as start JOIN sched_switch as end ON start.pid = end.next_pid
+--
+
+
Finally, the *WHERE* clause can be added, that will let you add filters on either or both events.
[source,c]
diff --git a/src/tracefs-sqlhist.c b/src/tracefs-sqlhist.c
index 003592291cb8..3592000e038d 100644
--- a/src/tracefs-sqlhist.c
+++ b/src/tracefs-sqlhist.c
@@ -39,6 +39,13 @@ enum field_type {
#define for_each_field(expr, field, table) \
for (expr = (table)->fields; expr; expr = (field)->next)
+#define TIMESTAMP_COMPARE "TIMESTAMP_DELTA"
+#define TIMESTAMP_USECS_COMPARE "TIMESTAMP_USECS_DELTA"
+#define EVENT_START "__START_EVENT__"
+#define EVENT_END "__END_EVENT__"
+#define TIMESTAMP_NSECS "TIMESTAMP"
+#define TIMESTAMP_USECS "TIMESTAMP_USECS"
+
struct field {
struct expr *next; /* private link list */
const char *system;
@@ -374,6 +381,44 @@ __hidden void *add_field(struct sqlhist_bison *sb,
struct sql_table *table = sb->table;
struct expr *expr;
struct field *field;
+ bool nsecs;
+
+ /* Check if this is a TIMESTAMP compare */
+ if ((nsecs = (strcmp(field_name, TIMESTAMP_COMPARE) == 0)) ||
+ strcmp(field_name, TIMESTAMP_USECS_COMPARE) == 0) {
+ const char *field_nameA;
+ const char *field_nameB;
+ struct expr *exprA;
+ struct expr *exprB;
+ struct field *fieldA;
+ struct field *fieldB;
+
+ if (nsecs) {
+ field_nameA = EVENT_END "." TIMESTAMP_NSECS;
+ field_nameB = EVENT_START "." TIMESTAMP_NSECS;
+ } else {
+ field_nameA = EVENT_END "." TIMESTAMP_USECS;
+ field_nameB = EVENT_START "." TIMESTAMP_USECS;
+ }
+
+ exprA = find_field(sb, field_nameA, NULL);
+ if (!exprA) {
+ create_field(fieldA, &exprA);
+ fieldA->next = table->fields;
+ table->fields = exprA;
+ fieldA->raw = field_nameA;
+ }
+
+ exprB = find_field(sb, field_nameB, NULL);
+ if (!exprB) {
+ create_field(fieldB, &exprB);
+ fieldB->next = table->fields;
+ table->fields = exprB;
+ fieldB->raw = field_nameB;
+ }
+
+ return add_compare(sb, exprA, exprB, COMPARE_SUB);
+ }
expr = find_field(sb, field_name, label);
if (expr)
@@ -597,17 +642,25 @@ static int update_vars(struct tep_handle *tep,
enum field_type ftype = FIELD_NONE;
struct tep_event *event;
struct field *field;
+ const char *extra_label;
const char *label;
const char *raw = event_field->raw;
const char *event_name;
const char *system;
const char *p;
int label_len = 0, event_len, system_len;
+ int extra_label_len = 0;
- if (expr == table->to)
+ if (expr == table->to) {
ftype = FIELD_TO;
- else if (expr == table->from)
+ extra_label = EVENT_END;
+ } else if (expr == table->from) {
ftype = FIELD_FROM;
+ extra_label = EVENT_START;
+ }
+
+ if (extra_label)
+ extra_label_len = strlen(extra_label);
p = strchr(raw, '.');
if (p) {
@@ -673,6 +726,13 @@ static int update_vars(struct tep_handle *tep,
goto found;
}
+ len = extra_label_len;
+ if (extra_label && !strncmp(raw, extra_label, len) &&
+ raw[len] == '.') {
+ /* Label matches and takes precedence */
+ goto found;
+ }
+
if (!strncmp(raw, system, system_len) &&
raw[system_len] == '.') {
raw += system_len + 1;
diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 6a817125419f..a94a1f28258a 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -49,6 +49,9 @@
#define SQL_5_SQL "select end.common_pid as pid, (end.common_timestamp.usecs - start.common_timestamp.usecs) as irq_lat from irq_disable as start join irq_enable as end on start.common_pid = end.common_pid, start.parent_offs == end.parent_offs where start.common_pid != 0"
#define SQL_5_START "irq_disable"
+#define SQL_6_EVENT "wakeup_lat_3"
+#define SQL_6_SQL "select start.pid, end.next_prio as prio, (end.TIMESTAMP_USECS - start.TIMESTAMP_USECS) as lat from sched_waking as start join sched_switch as end on start.pid = end.next_pid where (start.prio >= 1 && start.prio < 100) || !(start.pid >= 0 && start.pid <= 1) && end.prev_pid != 0"
+
#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
#define TRACEFS_DEFAULT2_PATH "/sys/kernel/debug/tracing"
@@ -420,6 +423,13 @@ static void test_instance_trace_sql(struct tracefs_instance *instance)
trace_seq_reset(&seq);
}
+ synth = tracefs_sql(tep, SQL_6_EVENT, SQL_6_SQL, NULL);
+ CU_TEST(synth != NULL);
+ ret = tracefs_synth_echo_cmd(&seq, synth);
+ CU_TEST(ret == 0);
+ tracefs_synth_free(synth);
+ trace_seq_reset(&seq);
+
trace_seq_destroy(&seq);
}
--
2.42.0
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