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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Tom Zanussi <zanussi@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH v4 04/10] tracing/boot: Support multiple histograms for each event
Date: Tue, 10 Aug 2021 11:07:36 +0900	[thread overview]
Message-ID: <162856125628.203126.15846930277378572120.stgit@devnote2> (raw)
In-Reply-To: <162856122550.203126.17607127017097781682.stgit@devnote2>

Add multiple histograms support for each event. This allows
user to set multiple histograms to an event.

ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] {
...
}

The 'N' is a digit started string and it can be omitted
for the default histogram.

For example, multiple hist triggers example in the
Documentation/trace/histogram.rst can be written as below;

ftrace.event.net.netif_receive_skb.hist {
	1 {
		keys = skbaddr.hex
		values = len
		filter = len < 0
	}
	2 {
		keys = skbaddr.hex
		values = len
		filter = len > 4096
	}
	3 {
		keys = skbaddr.hex
		values = len
		filter = len == 256
	}
	4 {
		keys = skbaddr.hex
		values = len
	}
	5 {
		keys = len
		values = common_preempt_count
	}
}

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 Changes in v3:
  - Fixes a build error when CONFIG_HIST_TRIGGERS=n.
---
 kernel/trace/trace_boot.c |   41 ++++++++++++++++++++++++++++++++---------
 1 file changed, 32 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index f024f27b3602..1a2b270e9cda 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -324,7 +324,7 @@ trace_boot_hist_add_handlers(struct xbc_node *hnode, char **bufp,
 /*
  * Histogram boottime tracing syntax.
  *
- * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist {
+ * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] {
  *	keys = <KEY>[,...]
  *	values = <VAL>[,...]
  *	sort = <SORT-KEY>[,...]
@@ -415,11 +415,37 @@ trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size)
 
 	return 0;
 }
+
+static void __init
+trace_boot_init_histograms(struct trace_event_file *file,
+			   struct xbc_node *hnode, char *buf, size_t size)
+{
+	struct xbc_node *node;
+	const char *p;
+
+	xbc_node_for_each_subkey(hnode, node) {
+		p = xbc_node_get_data(node);
+		if (!isdigit(p[0]))
+			continue;
+		/* All digit started node should be instances. */
+		if (trace_boot_compose_hist_cmd(node, buf, size) == 0) {
+			if (trigger_process_regex(file, buf) < 0)
+				pr_err("Failed to apply hist trigger: %s\n", buf);
+		}
+	}
+
+	if (xbc_node_find_child(hnode, "keys")) {
+		if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0)
+			if (trigger_process_regex(file, buf) < 0)
+				pr_err("Failed to apply hist trigger: %s\n", buf);
+	}
+}
 #else
-static int __init
-trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size)
+static void __init
+trace_boot_init_histograms(struct trace_event_file *file,
+			   struct xbc_node *hnode, char *buf, size_t size)
 {
-	return -EOPNOTSUPP;
+	/* do nothing */
 }
 #endif
 
@@ -465,11 +491,8 @@ trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
 				pr_err("Failed to apply an action: %s\n", buf);
 		}
 		anode = xbc_node_find_child(enode, "hist");
-		if (anode &&
-		    trace_boot_compose_hist_cmd(anode, buf, ARRAY_SIZE(buf)) == 0) {
-			if (trigger_process_regex(file, buf) < 0)
-				pr_err("Failed to apply hist trigger: %s\n", buf);
-		}
+		if (anode)
+			trace_boot_init_histograms(file, anode, buf, ARRAY_SIZE(buf));
 	} else if (xbc_node_find_value(enode, "actions", NULL))
 		pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n");
 


  parent reply	other threads:[~2021-08-10  2:07 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-10  2:07 [PATCH v4 00/10] tracing/boot: Add histogram syntax support in boot-time tracing Masami Hiramatsu
2021-08-10  2:07 ` [PATCH v4 01/10] tracing/boot: Fix a hist trigger dependency for boot time tracing Masami Hiramatsu
2021-08-10  2:07 ` [PATCH v4 02/10] tracing/boot: Add per-event histogram action options Masami Hiramatsu
2021-08-10  2:07 ` [PATCH v4 03/10] tracing/boot: Support multiple handlers for per-event histogram Masami Hiramatsu
2021-08-10  2:07 ` Masami Hiramatsu [this message]
2021-08-10  2:07 ` [PATCH v4 05/10] tracing/boot: Show correct histogram error command Masami Hiramatsu
2021-08-10  2:07 ` [PATCH v4 06/10] Documentation: tracing: Add histogram syntax to boot-time tracing Masami Hiramatsu
2021-08-10  2:07 ` [PATCH v4 07/10] tools/bootconfig: Support per-group/all event enabling option Masami Hiramatsu
2021-08-14  3:31   ` Masami Hiramatsu
2021-08-16 15:39     ` Steven Rostedt
2021-08-10  2:08 ` [PATCH v4 08/10] tools/bootconfig: Add histogram syntax support to bconf2ftrace.sh Masami Hiramatsu
2021-08-10  2:08 ` [PATCH v4 09/10] tools/bootconfig: Use per-group/all enable option in ftrace2bconf script Masami Hiramatsu
2021-08-10  2:08 ` [PATCH v4 10/10] bootconfig/tracing/ktest: Update ktest example for boot-time tracing Masami Hiramatsu

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