Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [RFC PATCH 2/3] tracing/boot: Add per-event histogram action options | Date | Tue, 3 Aug 2021 00:30:27 +0900 |
| |
Add a hist-trigger action syntax support to boot-time tracing. Currently, boot-time tracing supports per-event actions as option strings. However, for the histogram action, it has a special syntax and usually needs a long action definition. To make it readable and fit to the bootconfig syntax, this introduces a new options for histogram.
Here are the histogram action options for boot-time tracing.
ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist { keys = <KEY>[,...] values = <VAL>[,...] sort = <SORT-KEY>[,...] size = <ENTRIES> name = <HISTNAME> var { <VAR> = <EXPR> ... } pause|continue|clear onmax|onchange { var = <VAR>, <ACTION> [= <PARAM>] } onmatch { event = <EVENT>, <ACTION> [= <PARAM>] } filter = <FILTER> }
Where <ACTION> is one of below;
trace = <EVENT>, <ARG1>[, ...] save = <ARG1>[, ...] snapshot
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- kernel/trace/trace_boot.c | 200 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+)
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index e6dc9269ad75..56e92d34a88c 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -171,6 +171,200 @@ trace_boot_add_synth_event(struct xbc_node *node, const char *event) } #endif +#ifdef CONFIG_HIST_TRIGGERS +static int __init +append_printf(char **bufp, char *end, const char *fmt, ...) +{ + va_list args; + int ret; + + if (*bufp == end) + return -ENOSPC; + + va_start(args, fmt); + ret = vsnprintf(*bufp, end - *bufp, fmt, args); + if (ret < end - *bufp) { + *bufp += ret; + } else { + *bufp = end; + ret = -ERANGE; + } + va_end(args); + + return ret; +} + +static int __init +trace_boot_hist_add_array(struct xbc_node *hnode, char **bufp, + char *end, const char *key) +{ + struct xbc_node *knode, *anode; + const char *p; + + knode = xbc_node_find_child(hnode, key); + if (knode) { + anode = xbc_node_get_child(knode); + if (!anode) { + pr_err("hist.%s requires value(s).\n", key); + return -EINVAL; + } + + append_printf(bufp, end, "%s=", key); + xbc_array_for_each_value(anode, p) { + append_printf(bufp, end, "%s,", p); + } + (*bufp)[-1] = ':'; + } else + return -ENOENT; + + return 0; +} + +static int __init +trace_boot_hist_add_handler(struct xbc_node *hnode, char **bufp, + char *end, const char *param) +{ + struct xbc_node *knode, *anode; + const char *p; + + /* Compose 'handler' parameter */ + p = xbc_node_find_value(hnode, param, NULL); + if (!p) { + pr_err("hist.%s requires '%s' option.\n", + xbc_node_get_data(hnode), param); + return -EINVAL; + } + append_printf(bufp, end, "%s(%s).", xbc_node_get_data(hnode), p); + + /* Compose 'action' parameter */ + knode = xbc_node_find_child(hnode, "trace"); + if (!knode) + knode = xbc_node_find_child(hnode, "save"); + + if (knode) { + anode = xbc_node_get_child(knode); + if (!anode || !xbc_node_is_value(anode)) { + pr_err("hist.%s.%s requires value(s).\n", + xbc_node_get_data(hnode), + xbc_node_get_data(knode)); + return -EINVAL; + } + + append_printf(bufp, end, "%s(", xbc_node_get_data(knode)); + xbc_array_for_each_value(anode, p) { + append_printf(bufp, end, "%s,", p); + } + (*bufp)[-1] = ')'; + } else if (xbc_node_find_child(hnode, "snapshot")) { + append_printf(bufp, end, "snapshot()"); + } else { + pr_err("hist.%s requires an action.\n", + xbc_node_get_data(hnode)); + return -EINVAL; + } + append_printf(bufp, end, ":"); + + return 0; +} + +/* + * Histogram boottime tracing syntax. + * + * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist { + * keys = <KEY>[,...] + * values = <VAL>[,...] + * sort = <SORT-KEY>[,...] + * size = <ENTRIES> + * name = <HISTNAME> + * var { <VAR> = <EXPR> ... } + * pause|continue|clear + * onmax|onchange { var = <VAR>, <ACTION> [= <PARAM>] } + * onmatch { event = <EVENT>, <ACTION> [= <PARAM>] } + * filter = <FILTER> + * } + * + * Where <ACTION> are; + * + * trace = <EVENT>, <ARG1>[, ...] + * save = <ARG1>[, ...] + * snapshot + */ +static int __init +trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size) +{ + struct xbc_node *node, *knode; + char *end = buf + size; + const char *p; + int ret = 0; + + append_printf(&buf, end, "hist:"); + + ret = trace_boot_hist_add_array(hnode, &buf, end, "keys"); + if (ret < 0) { + if (ret == -ENOENT) + pr_err("hist requires keys.\n"); + return -EINVAL; + } + + ret = trace_boot_hist_add_array(hnode, &buf, end, "values"); + if (ret == -EINVAL) + return ret; + ret = trace_boot_hist_add_array(hnode, &buf, end, "sort"); + if (ret == -EINVAL) + return ret; + + p = xbc_node_find_value(hnode, "size", NULL); + if (p) + append_printf(&buf, end, "size=%s:", p); + + p = xbc_node_find_value(hnode, "name", NULL); + if (p) + append_printf(&buf, end, "name=%s:", p); + + node = xbc_node_find_child(hnode, "var"); + if (node) { + xbc_node_for_each_key_value(node, knode, p) { + append_printf(&buf, end, "%s=%s:", + xbc_node_get_data(knode), p); + } + } + + /* Histogram control attributes */ + if (xbc_node_find_child(hnode, "pause")) + append_printf(&buf, end, "pause:"); + if (xbc_node_find_child(hnode, "continue")) + append_printf(&buf, end, "continue:"); + if (xbc_node_find_child(hnode, "clear")) + append_printf(&buf, end, "clear:"); + + /* Histogram handler and actions */ + node = xbc_node_find_child(hnode, "onmax"); + if (node && trace_boot_hist_add_handler(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) + return -EINVAL; + node = xbc_node_find_child(hnode, "onmatch"); + if (node && trace_boot_hist_add_handler(node, &buf, end, "event") < 0) + return -EINVAL; + + /* Remove the last ':' */ + if (buf + size > end) + *(--buf) = '\0'; + + p = xbc_node_find_value(hnode, "filter", NULL); + if (p) + append_printf(&buf, end, " if %s", p); + + if (buf == end) { + pr_err("hist exceeds the max command length.\n"); + return -E2BIG; + } + + return 0; +} +#endif + static void __init trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode, struct xbc_node *enode) @@ -211,6 +405,12 @@ trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode, else if (trigger_process_regex(file, buf) < 0) 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); + } #endif if (xbc_node_find_value(enode, "enable", NULL)) {
| |