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tracing/boot: Support multiple histograms for each event 

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
	}
}

Link: https://lkml.kernel.org/r/162856125628.203126.15846930277378572120.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2021-08-10 11:07:36 +09:00 committed by Steven Rostedt (VMware)
parent 8993665abc
commit 17abd7c36c
1 changed files with 33 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
kernel/trace/trace_boot.c
View File

@ -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;
}
#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;
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 void __init
trace_boot_init_histograms(struct trace_event_file *file,
struct xbc_node *hnode, char *buf, size_t size)
{
/* 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");