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authorMasami Hiramatsu <mhiramat@kernel.org>2021-08-10 11:07:29 +0900
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-08-16 11:37:21 -0400
commit8993665abcce793f00815b3504a486dce70cc2b9 (patch)
tree9fc1b771c5768a19db19806f0606f6677cefa462 /kernel/trace
parente66ed86ca6c52488249e95f7b3a6a3d7d6ab5e1e (diff)
tracing/boot: Support multiple handlers for per-event histogram
Support multiple handlers for per-event histogram in boot-time tracing. Since the histogram can register multiple same handler-actions with different parameters, this expands the syntax to support such cases. With this update, the 'onmax', 'onchange' and 'onmatch' handler subkeys under per-event histogram option will take a number subkeys optionally as below. (see [.N]) ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist { onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] } onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] } } The 'N' must be a digit (or digit started word). Thus user can add several handler-actions to the histogram, for example, ftrace.event.SOMEGROUP.SOMEEVENT.hist { keys = SOME_ID; lat = common_timestamp.usecs-$ts0 onmatch.1 { event = GROUP1.STARTEVENT1 trace = latency_event, SOME_ID, $lat } onmatch.2 { event = GROUP2.STARTEVENT2 trace = latency_event, SOME_ID, $lat } } Then, it can trace the elapsed time from GROUP1.STARTEVENT1 to SOMEGROUP.SOMEEVENT, and from GROUP2.STARTEVENT2 to SOMEGROUP.SOMEEVENT with SOME_ID key. Link: https://lkml.kernel.org/r/162856124905.203126.14913731908137885922.stgit@devnote2 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_boot.c43
1 files changed, 35 insertions, 8 deletions
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 3d0e51368f51..f024f27b3602 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -245,8 +245,9 @@ trace_boot_hist_add_array(struct xbc_node *hnode, char **bufp,
}
static int __init
-trace_boot_hist_add_handler(struct xbc_node *hnode, char **bufp,
- char *end, const char *param)
+trace_boot_hist_add_one_handler(struct xbc_node *hnode, char **bufp,
+ char *end, const char *handler,
+ const char *param)
{
struct xbc_node *knode, *anode;
const char *p;
@@ -259,7 +260,7 @@ trace_boot_hist_add_handler(struct xbc_node *hnode, char **bufp,
xbc_node_get_data(hnode), param);
return -EINVAL;
}
- append_printf(bufp, end, ":%s(%s)", xbc_node_get_data(hnode), p);
+ append_printf(bufp, end, ":%s(%s)", handler, p);
/* Compose 'action' parameter */
knode = xbc_node_find_child(hnode, "trace");
@@ -294,6 +295,32 @@ trace_boot_hist_add_handler(struct xbc_node *hnode, char **bufp,
return 0;
}
+static int __init
+trace_boot_hist_add_handlers(struct xbc_node *hnode, char **bufp,
+ char *end, const char *param)
+{
+ struct xbc_node *node;
+ const char *p, *handler;
+ int ret;
+
+ handler = xbc_node_get_data(hnode);
+
+ 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. */
+ ret = trace_boot_hist_add_one_handler(node, bufp, end, handler, param);
+ if (ret < 0)
+ break;
+ }
+
+ if (xbc_node_find_child(hnode, param))
+ ret = trace_boot_hist_add_one_handler(hnode, bufp, end, handler, param);
+
+ return ret;
+}
+
/*
* Histogram boottime tracing syntax.
*
@@ -305,8 +332,8 @@ trace_boot_hist_add_handler(struct xbc_node *hnode, char **bufp,
* name = <HISTNAME>
* var { <VAR> = <EXPR> ... }
* pause|continue|clear
- * onmax|onchange { var = <VAR>; <ACTION> [= <PARAM>] }
- * onmatch { event = <EVENT>; <ACTION> [= <PARAM>] }
+ * onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] }
+ * onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] }
* filter = <FILTER>
* }
*
@@ -368,13 +395,13 @@ trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size)
/* Histogram handler and actions */
node = xbc_node_find_child(hnode, "onmax");
- if (node && trace_boot_hist_add_handler(node, &buf, end, "var") < 0)
+ if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
return -EINVAL;
node = xbc_node_find_child(hnode, "onchange");
- if (node && trace_boot_hist_add_handler(node, &buf, end, "var") < 0)
+ if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
return -EINVAL;
node = xbc_node_find_child(hnode, "onmatch");
- if (node && trace_boot_hist_add_handler(node, &buf, end, "event") < 0)
+ if (node && trace_boot_hist_add_handlers(node, &buf, end, "event") < 0)
return -EINVAL;
p = xbc_node_find_value(hnode, "filter", NULL);

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