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Groups > linux.kernel > #1254052

[PATCH v11 10/28] tracing: Add hist trigger support for multiple values ('vals=' param)

From Tom Zanussi <tom.zanussi@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCH v11 10/28] tracing: Add hist trigger support for multiple values ('vals=' param)
Date 2015-10-22 20:30 +0200
Message-ID <qmsMG-299-9@gated-at.bofh.it> (permalink)
References <qmsD0-1Xu-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Allow users to specify trace event fields to use in aggregated sums
via a new 'vals=' keyword.  Before this addition, the only aggregated
sum supported was the implied value 'hitcount'.  With this addition,
'hitcount' is also supported as an explicit value field, as is any
numeric trace event field.

This expands the hist trigger syntax from this:

  # echo hist:keys=xxx [ if filter] > event/trigger

to this:

  # echo hist:keys=xxx:vals=yyy [ if filter] > event/trigger

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
 kernel/trace/trace.c             | 12 ++++---
 kernel/trace/trace_events_hist.c | 75 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 81 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6d5870b..98817d5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3799,14 +3799,16 @@ static const char readme_msg[] =
 #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            [:values=<field1[,field2,...]]\n"
 	"\t            [:size=#entries]\n"
 	"\t            [if <filter>]\n\n"
 	"\t    When a matching event is hit, an entry is added to a hash\n"
-	"\t    table using the key named, and the value of a sum called\n"
-	"\t    'hitcount' is incremented.  Keys correspond to fields in the\n"
-	"\t    event's format description.  Keys can be any field.  The\n"
-	"\t    'size' parameter can be  used to specify more or fewer than\n"
-	"\t    the default 2048 entries for the hashtable size.\n\n"
+	"\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    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 376626b..efa62b3 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -75,6 +75,7 @@ enum hist_field_flags {
 
 struct hist_trigger_attrs {
 	char		*keys_str;
+	char		*vals_str;
 	unsigned int	map_bits;
 };
 
@@ -155,6 +156,7 @@ static int parse_map_size(char *str)
 static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
 {
 	kfree(attrs->keys_str);
+	kfree(attrs->vals_str);
 	kfree(attrs);
 }
 
@@ -173,6 +175,10 @@ static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str)
 		if (!strncmp(str, "keys", strlen("keys")) ||
 		    !strncmp(str, "key", strlen("key")))
 			attrs->keys_str = kstrdup(str, GFP_KERNEL);
+		else if (!strncmp(str, "values", strlen("values")) ||
+			 !strncmp(str, "vals", strlen("vals")) ||
+			 !strncmp(str, "val", strlen("val")))
+			attrs->vals_str = kstrdup(str, GFP_KERNEL);
 		else if (!strncmp(str, "size", strlen("size"))) {
 			int map_bits = parse_map_size(str);
 
@@ -256,13 +262,66 @@ static int create_hitcount_val(struct hist_trigger_data *hist_data)
 	return 0;
 }
 
+static int create_val_field(struct hist_trigger_data *hist_data,
+			    unsigned int val_idx,
+			    struct trace_event_file *file,
+			    char *field_str)
+{
+	struct ftrace_event_field *field = NULL;
+	unsigned long flags = 0;
+	int ret = 0;
+
+	field = trace_find_event_field(file->event_call, field_str);
+	if (!field) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	hist_data->fields[val_idx] = create_hist_field(field, flags);
+	if (!hist_data->fields[val_idx]) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	hist_data->n_vals++;
+ out:
+	return ret;
+}
+
 static int create_val_fields(struct hist_trigger_data *hist_data,
 			     struct trace_event_file *file)
 {
+	unsigned int vals_max = TRACING_MAP_FIELDS_MAX - TRACING_MAP_KEYS_MAX;
+	char *fields_str, *field_str;
+	unsigned int i, j;
 	int ret;
 
 	ret = create_hitcount_val(hist_data);
+	if (ret)
+		goto out;
 
+	fields_str = hist_data->attrs->vals_str;
+	if (!fields_str)
+		goto out;
+
+	strsep(&fields_str, "=");
+	if (!fields_str)
+		goto out;
+
+	vals_max = TRACING_MAP_FIELDS_MAX - TRACING_MAP_KEYS_MAX;
+
+	for (i = 0, j = 1; i < vals_max; i++) {
+		field_str = strsep(&fields_str, ",");
+		if (!field_str)
+			break;
+		if (!strcmp(field_str, "hitcount"))
+			continue;
+		ret = create_val_field(hist_data, j++, file, field_str);
+		if (ret)
+			goto out;
+	}
+	if (fields_str)
+		ret = -EINVAL;
+ out:
 	return ret;
 }
 
@@ -534,6 +593,12 @@ hist_trigger_entry_print(struct seq_file *m,
 	seq_printf(m, " hitcount: %10llu",
 		   tracing_map_read_sum(elt, HITCOUNT_IDX));
 
+	for (i = 1; i < hist_data->n_vals; i++) {
+		seq_printf(m, "  %s: %10llu",
+			   hist_data->fields[i]->field->name,
+			   tracing_map_read_sum(elt, i));
+	}
+
 	seq_puts(m, "\n");
 }
 
@@ -641,7 +706,15 @@ static int event_hist_trigger_print(struct seq_file *m,
 	}
 
 	seq_puts(m, ":vals=");
-	seq_puts(m, "hitcount");
+
+	for (i = 0; i < hist_data->n_vals; i++) {
+		if (i == 0)
+			seq_puts(m, "hitcount");
+		else {
+			seq_puts(m, ",");
+			hist_field_print(m, hist_data->fields[i]);
+		}
+	}
 
 	seq_puts(m, ":sort=");
 	seq_puts(m, "hitcount");
-- 
1.9.3

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Thread

[PATCH 00/28] tracing: 'hist' triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:20 +0200
  [PATCH v11 16/28] tracing: Add hist trigger 'sym' and 'sym-offset' modifiers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:20 +0200
  [PATCH v11 12/28] tracing: Add hist trigger support for user-defined sorting ('sort=' param) Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:20 +0200
  [PATCH v11 01/28] tracing: Update cond flag when enabling or disabling a trigger Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  [PATCH v11 27/28] kselftests/ftrace : Add event trigger testcases Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  [PATCH v11 10/28] tracing: Add hist trigger support for multiple values ('vals=' param) Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  [PATCH v11 06/28] tracing: Add a per-event-trigger 'paused' field Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  [PATCH v11 25/28] tracing: Add support for named triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  [PATCH v11 18/28] tracing: Add hist trigger 'syscall' modifier Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  [PATCH v11 03/28] tracing: Make event trigger functions available Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  [PATCH v11 04/28] tracing: Add event record param to trigger_ops.func() Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  Re: [PATCH 00/28] tracing: 'hist' triggers Steven Rostedt <rostedt@goodmis.org> - 2015-10-22 20:30 +0200
    Re: [PATCH 00/28] tracing: 'hist' triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:40 +0200
  [PATCH v11 05/28] tracing: Add get_syscall_name() Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-22 20:30 +0200
  Re: [PATCH v11 08/28] tracing: Add lock-free tracing_map Namhyung Kim <namhyung@kernel.org> - 2015-10-29 09:40 +0100
    Re: [PATCH v11 08/28] tracing: Add lock-free tracing_map Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-10-29 19:40 +0100

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