Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH v2 4/9] tracing/boot: Support multiple histograms for each event | Date | Fri, 6 Aug 2021 01:25:51 +0900 |
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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> --- 0 files changed
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 0db0775d37af..1f4b80f6fcb6 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -303,7 +303,7 @@ 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>[,...] @@ -392,6 +392,32 @@ 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); + } + +} #endif static void __init @@ -435,11 +461,8 @@ 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)); #endif if (xbc_node_find_value(enode, "enable", NULL)) {
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