[PATCH v2 03/21] libtracefs: Add comparing start and end fields in tracefs_sql()

From: Steven Rostedt
Date: Tue Aug 03 2021 - 00:24:24 EST


From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>

Add comparing a field and showing the differences between start and end
for tracefs_sql().

For example:

SELECT (end.common_timestamp.usecs - start.common_timestamp.usecs) AS
lat FROM sched_waking AS start JOIN sched_switch AS end ON
start.pid = stop.next_pid

Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
src/sqlhist-parse.h | 1 +
src/sqlhist.y | 16 ++++++++
src/tracefs-sqlhist.c | 85 ++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/src/sqlhist-parse.h b/src/sqlhist-parse.h
index aa5232eea451..aeb1738d693f 100644
--- a/src/sqlhist-parse.h
+++ b/src/sqlhist-parse.h
@@ -58,6 +58,7 @@ int table_start(struct sqlhist_bison *sb);
void *add_field(struct sqlhist_bison *sb, const char *field, const char *label);

int add_match(struct sqlhist_bison *sb, void *A, void *B);
+void *add_compare(struct sqlhist_bison *sb, void *A, void *B, enum compare_type type);

int add_selection(struct sqlhist_bison *sb, void *item, const char *label);
int add_from(struct sqlhist_bison *sb, void *item);
diff --git a/src/sqlhist.y b/src/sqlhist.y
index ecb0a0ed44b3..1ba3bf62ee43 100644
--- a/src/sqlhist.y
+++ b/src/sqlhist.y
@@ -48,6 +48,7 @@ extern void yyerror(char *fmt, ...);
%type <string> name label

%type <expr> selection_expr field item named_field join_clause
+%type <expr> selection_addition

%%

@@ -85,6 +86,21 @@ selection :
selection_expr :
field
| '(' field ')' { $$ = $2; }
+ | selection_addition
+ | '(' selection_addition ')' { $$ = $2; }
+ ;
+
+selection_addition :
+ field '+' field
+ {
+ $$ = add_compare(sb, $1, $3, COMPARE_ADD);
+ CHECK_RETURN_PTR($$);
+ }
+ | field '-' field
+ {
+ $$ = add_compare(sb, $1, $3, COMPARE_SUB);
+ CHECK_RETURN_PTR($$);
+ }
;

item :
diff --git a/src/tracefs-sqlhist.c b/src/tracefs-sqlhist.c
index 7ec0c11b902e..cf2661773679 100644
--- a/src/tracefs-sqlhist.c
+++ b/src/tracefs-sqlhist.c
@@ -42,17 +42,32 @@ struct field {
const char *field;
};

+struct filter {
+ enum filter_type type;
+ struct expr *lval;
+ struct expr *rval;
+};
+
struct match {
struct match *next;
struct expr *lval;
struct expr *rval;
};

+struct compare {
+ enum compare_type type;
+ struct expr *lval;
+ struct expr *rval;
+ const char *name;
+};
+
enum expr_type
{
EXPR_NUMBER,
EXPR_STRING,
EXPR_FIELD,
+ EXPR_FILTER,
+ EXPR_COMPARE,
};

struct expr {
@@ -61,6 +76,8 @@ struct expr {
enum expr_type type;
union {
struct field field;
+ struct filter filter;
+ struct compare compare;
const char *string;
long number;
};
@@ -209,8 +226,14 @@ __hidden int add_selection(struct sqlhist_bison *sb, void *select,
switch (expr->type) {
case EXPR_FIELD:
break;
+ case EXPR_COMPARE:
+ if (!name)
+ return -1;
+ expr->compare.name = name;
+ break;
case EXPR_NUMBER:
case EXPR_STRING:
+ case EXPR_FILTER:
default:
return -1;
}
@@ -277,8 +300,10 @@ static void *create_expr(enum expr_type type, struct expr **expr_p)

switch (type) {
case EXPR_FIELD: return &expr->field;
+ case EXPR_COMPARE: return &expr->compare;
case EXPR_NUMBER: return &expr->number;
case EXPR_STRING: return &expr->string;
+ case EXPR_FILTER: return &expr->filter;
}

return NULL;
@@ -292,6 +317,9 @@ static void *create_expr(enum expr_type type, struct expr **expr_p)
#define create_field(var, expr) \
__create_expr(var, struct field, FIELD, expr)

+#define create_compare(var, expr) \
+ __create_expr(var, struct compare, COMPARE, expr)
+
__hidden void *add_field(struct sqlhist_bison *sb,
const char *field_name, const char *label)
{
@@ -331,6 +359,21 @@ __hidden int add_match(struct sqlhist_bison *sb, void *A, void *B)

return 0;
}
+__hidden void *add_compare(struct sqlhist_bison *sb,
+ void *A, void *B, enum compare_type type)
+{
+ struct compare *compare;
+ struct expr *expr;
+
+ create_compare(compare, &expr);
+
+ compare = &expr->compare;
+ compare->lval = A;
+ compare->rval = B;
+ compare->type = type;
+
+ return expr;
+}

__hidden int add_from(struct sqlhist_bison *sb, void *item)
{
@@ -522,6 +565,39 @@ static void assign_match(const char *system, const char *event,
}
}

+static int build_compare(struct tracefs_synth *synth,
+ const char *system, const char *event,
+ struct compare *compare)
+{
+ const char *start_field;
+ const char *end_field;
+ struct field *lval, *rval;
+ enum tracefs_synth_calc calc;
+ int ret;
+
+ lval = &compare->lval->field;
+ rval = &compare->rval->field;
+
+ if (lval->system == system &&
+ lval->event == event) {
+ start_field = lval->field;
+ end_field = rval->field;
+ calc = TRACEFS_SYNTH_DELTA_START;
+ } else {
+ start_field = rval->field;
+ end_field = lval->field;
+ calc = TRACEFS_SYNTH_DELTA_END;
+ }
+
+ if (compare->type == COMPARE_ADD)
+ calc = TRACEFS_SYNTH_ADD;
+
+ ret = tracefs_synth_add_compare_field(synth, start_field,
+ end_field, calc,
+ compare->name);
+ return ret;
+}
+
static struct tracefs_synth *build_synth(struct tep_handle *tep,
const char *name,
struct sql_table *table)
@@ -602,7 +678,14 @@ static struct tracefs_synth *build_synth(struct tep_handle *tep,
goto free;
continue;
}
- goto free;
+
+ if (expr->type != EXPR_COMPARE)
+ goto free;
+
+ ret = build_compare(synth, start_system, end_system,
+ &expr->compare);
+ if (ret < 0)
+ goto free;
}

return synth;
--
2.30.2