From patchwork Fri Aug 13 02:16:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12434583 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5683C43216 for ; Fri, 13 Aug 2021 02:17:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93EEE61101 for ; Fri, 13 Aug 2021 02:17:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238206AbhHMCR7 (ORCPT ); Thu, 12 Aug 2021 22:17:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:44618 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237705AbhHMCRx (ORCPT ); Thu, 12 Aug 2021 22:17:53 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3BA46610E9; Fri, 13 Aug 2021 02:17:26 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.94.2) (envelope-from ) id 1mEMlA-003wVy-TV; Thu, 12 Aug 2021 22:17:24 -0400 From: Steven Rostedt To: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Tom Zanussi , Daniel Bristot de Oliveira , Masami Hiramatsu , Namhyung Kim , linux-rt-users , Clark Williams , "Steven Rostedt (VMware)" Subject: [PATCH 4/7] libtracefs: Add API tracefs_synth_snapshot() Date: Thu, 12 Aug 2021 22:16:52 -0400 Message-Id: <20210813021655.939819-5-rostedt@goodmis.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210813021655.939819-1-rostedt@goodmis.org> References: <20210813021655.939819-1-rostedt@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: "Steven Rostedt (VMware)" Add new API tracefs_synth_snapshot() Where this will add "actions" to the synthetic event descriptor and also add other features besides "onmatch()" such that the output can be: onmax($lat).trace(latency,$lat):onmax($lat).snapshot That will trace the latency when it hits a maximum, and also take a snapshot of the buffer. Signed-off-by: Steven Rostedt (VMware) --- Documentation/libtracefs-synth2.txt | 11 +++++++++- include/tracefs.h | 2 ++ src/tracefs-hist.c | 34 +++++++++++++++++++++++++++++ 3 files changed, 46 insertions(+), 1 deletion(-) diff --git a/Documentation/libtracefs-synth2.txt b/Documentation/libtracefs-synth2.txt index a74e88ec0eda..194a4e021f62 100644 --- a/Documentation/libtracefs-synth2.txt +++ b/Documentation/libtracefs-synth2.txt @@ -4,7 +4,7 @@ libtracefs(3) NAME ---- tracefs_synth_create, tracefs_synth_destroy, tracefs_synth_show,tracefs_synth_complete, -tracefs_synth_get_start_hist,tracefs_synth_trace - Creation of synthetic events +tracefs_synth_get_start_hist,tracefs_synth_trace,tracefs_synth_snapshot - Creation of synthetic events SYNOPSIS -------- @@ -23,6 +23,8 @@ struct tracefs_hist pass:[*]tracefs_synth_get_start_hist(struct tracefs_synth pa int tracefs_synth_trace(struct tracefs_synth pass:[*]synth, enum tracefs_synth_handler type, const char pass:[*]var); +int tracefs_synth_snapshot(struct tracefs_synth pass:[*]synth, + enum tracefs_synth_handler type, const char pass:[*]var); -- DESCRIPTION @@ -75,6 +77,13 @@ when the given variable _var_ hits a new max for the matching keys. Or *TRACEFS_SYNTH_HANDLE_CHANGE* for when the _var_ changes. _var_ must be one of the _name_ elements used in *tracefs_synth_add_end_field*(3). +*tracefs_synth_snapshot*() When the given variable _var_ is either a new max if +_handler_ is TRACEFS_SYNTH_HANDLE_MAX_ or simpy changed if TRACEFS_SYNTH_HANDLE_CHANGE_ +then take a "snapshot" of the buffer. The snapshot moves the normal "trace" buffer +into a "snapshot" buffer, that can be accessed via the "snapshot" file in the +top level tracefs directory, or one of the instances. _var_ changes. _var_ must be one of +the _name_ elements used in *tracefs_synth_add_end_field*(3). + RETURN VALUE ------------ Returns zero on success or -1 on error. diff --git a/include/tracefs.h b/include/tracefs.h index 2faa564a860f..45a5bb2df2de 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -478,6 +478,8 @@ int tracefs_synth_append_end_filter(struct tracefs_synth *synth, const char *val); int tracefs_synth_trace(struct tracefs_synth *synth, enum tracefs_synth_handler type, const char *field); +int tracefs_synth_snapshot(struct tracefs_synth *synth, + enum tracefs_synth_handler type, const char *field); bool tracefs_synth_complete(struct tracefs_synth *synth); struct tracefs_hist *tracefs_synth_get_start_hist(struct tracefs_synth *synth); int tracefs_synth_create(struct tracefs_instance *instance, diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c index 562ec65088a9..2c9c37b8ec23 100644 --- a/src/tracefs-hist.c +++ b/src/tracefs-hist.c @@ -524,6 +524,7 @@ int tracefs_hist_append_filter(struct tracefs_hist *hist, enum action_type { ACTION_NONE, ACTION_TRACE, + ACTION_SNAPSHOT, }; struct action { @@ -1414,6 +1415,36 @@ int tracefs_synth_trace(struct tracefs_synth *synth, return 0; } +/** + * tracefs_synth_snapshot - create a snapshot command to the histogram + * @synth: The tracefs_synth descriptor + * @type: The type of handler to attach the snapshot action with + * @field: The field for handlers onmax and onchange + * + * Add the action to do a snapshot for handlers onmax and onchange. + * + * Returns 0 on succes, -1 on error. + */ +int tracefs_synth_snapshot(struct tracefs_synth *synth, + enum tracefs_synth_handler type, const char *field) +{ + struct action *action; + + if (!synth || !field || (type == TRACEFS_SYNTH_HANDLE_MATCH)) { + errno = EINVAL; + return -1; + } + + action = create_action(type, synth, field); + if (!action) + return -1; + + action->type = ACTION_SNAPSHOT; + action->handler = type; + add_action(synth, action); + return 0; +} + static char *create_synthetic_event(struct tracefs_synth *synth) { char *synthetic_event; @@ -1562,6 +1593,9 @@ static char *create_actions(char *hist, struct tracefs_synth *synth) case ACTION_TRACE: hist = create_trace(hist, synth); break; + case ACTION_SNAPSHOT: + hist = append_string(hist, NULL, ".snapshot()"); + break; default: continue; }