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Groups > linux.kernel > #1236691

[PATCH v10 11/26] tracing: Add hist trigger support for compound keys

From Tom Zanussi <tom.zanussi@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCH v10 11/26] tracing: Add hist trigger support for compound keys
Date 2015-09-30 21:20 +0200
Message-ID <qev52-5JG-69@gated-at.bofh.it> (permalink)
References <qev4Z-5JG-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Allow users to specify multiple trace event fields to use in keys by
allowing multiple fields in the 'keys=' keyword.  With this addition,
any unique combination of any of the fields named in the 'keys'
keyword will result in a new entry being added to the hash table.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
 kernel/trace/trace.c             | 10 ++++++----
 kernel/trace/trace_events_hist.c | 40 ++++++++++++++++++++++++++++++----------
 2 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 396a9b8..7380d8d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3787,7 +3787,7 @@ static const char readme_msg[] =
 	"\t   Filters can be ignored when removing a trigger.\n"
 #ifdef CONFIG_HIST_TRIGGERS
 	"      hist trigger\t- If set, event hits are aggregated into a hash table\n"
-	"\t    Format: hist:keys=<field1>\n"
+	"\t    Format: hist:keys=<field1>[,field2,...]\n"
 	"\t            [:values=<field1[,field2,...]]\n"
 	"\t            [:size=#entries]\n"
 	"\t            [if <filter>]\n\n"
@@ -3795,9 +3795,11 @@ static const char readme_msg[] =
 	"\t    table using the key(s) and value(s) named, and the value of a\n"
 	"\t    sum called 'hitcount' is incremented.  Keys and values\n"
 	"\t    correspond to fields in the event's format description.  Keys\n"
-	"\t    can be any field.  Values must correspond to numeric fields.\n"
-	"\t    The 'size' parameter can be  used to specify more or fewer\n"
-	"\t    than the default 2048 entries for the hashtable size.\n\n"
+	"\t    can be any field.  Compound keys consisting of up to two\n"
+	"\t    fields can be specified by the 'keys' keyword.  Values must\n"
+	"\t    correspond to numeric fields.  The 'size' parameter can be\n"
+	"\t    used to specify more or fewer than the default 2048 entries\n"
+	"\t    for the hashtable size.\n\n"
 	"\t    Reading the 'hist' file for the event will dump the hash\n"
 	"\t    table in its entirety to stdout."
 #endif
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index efa62b3..112b8a2 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -32,6 +32,7 @@ struct hist_field {
 	unsigned long			flags;
 	hist_field_fn_t			fn;
 	unsigned int			size;
+	unsigned int			offset;
 };
 
 static u64 hist_field_counter(struct hist_field *field, void *event)
@@ -64,8 +65,8 @@ DEFINE_HIST_FIELD_FN(s8);
 DEFINE_HIST_FIELD_FN(u8);
 
 #define HITCOUNT_IDX		0
-#define HIST_KEY_MAX		1
-#define HIST_KEY_SIZE_MAX	MAX_FILTER_STR_VAL
+#define HIST_KEY_MAX		2
+#define HIST_KEY_SIZE_MAX	(MAX_FILTER_STR_VAL + sizeof(u64))
 
 enum hist_field_flags {
 	HIST_FIELD_HITCOUNT	= 1,
@@ -327,6 +328,7 @@ static int create_val_fields(struct hist_trigger_data *hist_data,
 
 static int create_key_field(struct hist_trigger_data *hist_data,
 			    unsigned int key_idx,
+			    unsigned int key_offset,
 			    struct trace_event_file *file,
 			    char *field_str)
 {
@@ -353,7 +355,8 @@ static int create_key_field(struct hist_trigger_data *hist_data,
 
 	key_size = ALIGN(key_size, sizeof(u64));
 	hist_data->fields[key_idx]->size = key_size;
-	hist_data->key_size = key_size;
+	hist_data->fields[key_idx]->offset = key_offset;
+	hist_data->key_size += key_size;
 	if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
 		ret = -EINVAL;
 		goto out;
@@ -368,7 +371,7 @@ static int create_key_field(struct hist_trigger_data *hist_data,
 static int create_key_fields(struct hist_trigger_data *hist_data,
 			     struct trace_event_file *file)
 {
-	unsigned int i, n_vals = hist_data->n_vals;
+	unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
 	char *fields_str, *field_str;
 	int ret = -EINVAL;
 
@@ -384,9 +387,11 @@ static int create_key_fields(struct hist_trigger_data *hist_data,
 		field_str = strsep(&fields_str, ",");
 		if (!field_str)
 			break;
-		ret = create_key_field(hist_data, i, file, field_str);
+		ret = create_key_field(hist_data, i, key_offset,
+				       file, field_str);
 		if (ret < 0)
 			goto out;
+		key_offset += ret;
 	}
 	if (fields_str) {
 		ret = -EINVAL;
@@ -451,7 +456,10 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
 			else
 				cmp_fn = tracing_map_cmp_num(field->size,
 							     field->is_signed);
-			idx = tracing_map_add_key_field(map, 0, cmp_fn);
+			idx = tracing_map_add_key_field(map,
+							hist_field->offset,
+							cmp_fn);
+
 		} else
 			idx = tracing_map_add_sum_field(map);
 
@@ -531,6 +539,7 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
 static void event_hist_trigger(struct event_trigger_data *data, void *rec)
 {
 	struct hist_trigger_data *hist_data = data->private_data;
+	char compound_key[HIST_KEY_SIZE_MAX];
 	struct hist_field *key_field;
 	struct tracing_map_elt *elt;
 	u64 field_contents;
@@ -542,6 +551,9 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec)
 		return;
 	}
 
+	if (hist_data->n_keys > 1)
+		memset(compound_key, 0, hist_data->key_size);
+
 	for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
 		key_field = hist_data->fields[i];
 
@@ -550,8 +562,16 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec)
 			key = (void *)(unsigned long)field_contents;
 		else
 			key = (void *)&field_contents;
+
+		if (hist_data->n_keys > 1) {
+			memcpy(compound_key + key_field->offset, key,
+			       key_field->size);
+		}
 	}
 
+	if (hist_data->n_keys > 1)
+		key = compound_key;
+
 	elt = tracing_map_insert(hist_data->map, key);
 	if (elt)
 		hist_trigger_elt_update(hist_data, elt, rec);
@@ -580,11 +600,11 @@ hist_trigger_entry_print(struct seq_file *m,
 
 		if (key_field->flags & HIST_FIELD_STRING) {
 			seq_printf(m, "%s: %-50s", key_field->field->name,
-				   (char *)key);
+				   (char *)(key + key_field->offset));
 		} else {
-			uval = *(u64 *)key;
-			seq_printf(m, "%s: %10llu",
-				   key_field->field->name, uval);
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: %10llu", key_field->field->name,
+				   uval);
 		}
 	}
 
-- 
1.9.3

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Thread

[PATCH 00/26] tracing: 'hist' triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 06/26] tracing: Add a per-event-trigger 'paused' field Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 12/26] tracing: Add hist trigger support for user-defined sorting ('sort=' param) Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 01/26] tracing: Update cond flag when enabling or disabling a trigger Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 22/26] tracing: Add enable_hist/disable_hist triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 13/26] tracing: Add hist trigger support for pausing and continuing a trace Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 17/26] tracing: Add hist trigger 'execname' modifier Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 19/26] tracing: Add hist trigger support for stacktraces as keys Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 18/26] tracing: Add hist trigger 'syscall' modifier Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 04/26] tracing: Add event record param to trigger_ops.func() Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 14/26] tracing: Add hist trigger support for clearing a trace Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 26/26] tracing: Add support for named hist triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 21/26] tracing: Remove restriction on string position in hist trigger keys Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 16/26] tracing: Add hist trigger 'sym' and 'sym-offset' modifiers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200
  [PATCH v10 11/26] tracing: Add hist trigger support for compound keys Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-09-30 21:20 +0200

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