From: Tom Zanussi <zanussi@kernel.org>
To: rostedt@goodmis.org
Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org,
vedang.patel@intel.com, bigeasy@linutronix.de,
joel@joelfernandes.org, mathieu.desnoyers@efficios.com,
julia@ni.com, linux-kernel@vger.kernel.org,
linux-rt-users@vger.kernel.org
Subject: [PATCH v15 02/15] tracing: Make hist trigger Documentation better reflect actions/handlers
Date: Wed, 13 Feb 2019 17:42:42 -0600 [thread overview]
Message-ID: <c2fe4144678829c70cad67aaa847dca27d57cb83.1550100284.git.tom.zanussi@linux.intel.com> (raw)
In-Reply-To: <cover.1550100284.git.tom.zanussi@linux.intel.com>
In-Reply-To: <cover.1550100284.git.tom.zanussi@linux.intel.com>
From: Tom Zanussi <tom.zanussi@linux.intel.com>
The action/handler code refactoring didn't change the action/handler
syntax, but did generalize it - the Documentation should reflect that.
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
Documentation/trace/histogram.rst | 56 ++++++++++++++++++++++++++++++---------
1 file changed, 43 insertions(+), 13 deletions(-)
diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst
index 7dda76503127..63e522107e59 100644
--- a/Documentation/trace/histogram.rst
+++ b/Documentation/trace/histogram.rst
@@ -25,7 +25,7 @@ Documentation written by Tom Zanussi
hist:keys=<field1[,field2,...]>[:values=<field1[,field2,...]>]
[:sort=<field1[,field2,...]>][:size=#entries][:pause][:continue]
- [:clear][:name=histname1] [if <filter>]
+ [:clear][:name=histname1][:<handler>.<action>] [if <filter>]
When a matching event is hit, an entry is added to a hash table
using the key(s) and value(s) named. Keys and values correspond to
@@ -1831,21 +1831,51 @@ and looks and behaves just like any other event::
Like any other event, once a histogram is enabled for the event, the
output can be displayed by reading the event's 'hist' file.
-2.2.3 Hist trigger 'actions'
-----------------------------
+2.2.3 Hist trigger 'handlers' and 'actions'
+-------------------------------------------
-A hist trigger 'action' is a function that's executed whenever a
-histogram entry is added or updated.
+A hist trigger 'action' is a function that's executed (in most cases
+conditionally) whenever a histogram entry is added or updated.
-The default 'action' if no special function is explicitly specified is
-as it always has been, to simply update the set of values associated
-with an entry. Some applications, however, may want to perform
-additional actions at that point, such as generate another event, or
-compare and save a maximum.
+When a histogram entry is added or updated, a hist trigger 'handler'
+is what decides whether the corresponding action is actually invoked
+or not.
-The following additional actions are available. To specify an action
-for a given event, simply specify the action between colons in the
-hist trigger specification.
+Hist trigger handlers and actions are paired together in the general
+form:
+
+ <handler>.<action>
+
+To specify a handler.action pair for a given event, simply specify
+that handler.action pair between colons in the hist trigger
+specification.
+
+In theory, any handler can be combined with any action, but in
+practice, not every handler.action combination is currently supported;
+if a given handler.action combination isn't supported, the hist
+trigger will fail with -EINVAL;
+
+The default 'handler.action' if none is explicity specified is as it
+always has been, to simply update the set of values associated with an
+entry. Some applications, however, may want to perform additional
+actions at that point, such as generate another event, or compare and
+save a maximum.
+
+The supported handlers and actions are listed below, and each is
+described in more detail in the following paragraphs, in the context
+of descriptions of some common and useful handler.action combinations.
+
+The available handlers are:
+
+ - onmatch(matching.event) - invoke action on any addition or update
+ - onmax(var) - invoke action if var exceeds current max
+
+The available actions are:
+
+ - <synthetic_event_name>(param list) - generate synthetic event
+ - save(field,...) - save current event fields
+
+The following commonly-used handler.action pairs are available:
- onmatch(matching.event).<synthetic_event_name>(param list)
--
2.14.1
next prev parent reply other threads:[~2019-02-13 23:44 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-13 23:42 [PATCH v15 00/15] tracing: Hist trigger snapshot and onchange additions Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 01/15] tracing: Refactor hist trigger action code Tom Zanussi
2019-02-13 23:42 ` Tom Zanussi [this message]
2019-02-13 23:42 ` [PATCH v15 03/15] tracing: Split up onmatch action data Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 04/15] tracing: Generalize hist trigger onmax and save action Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 05/15] tracing: Add conditional snapshot Tom Zanussi
2019-02-14 23:11 ` Steven Rostedt
2019-02-14 23:25 ` Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 06/15] tracing: Add hist trigger snapshot() action Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 07/15] tracing: Add hist trigger snapshot() action Documentation Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 08/15] tracing: Add hist trigger onchange() handler Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 09/15] tracing: Add hist trigger onchange() handler Documentation Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 10/15] tracing: Add alternative synthetic event trace action syntax Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 11/15] tracing: Add SPDX license GPL-2.0 license identifier to inter-event testcases Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 12/15] tracing: Add hist trigger snapshot() action test case Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 13/15] tracing: Add hist trigger onchange() handler " Tom Zanussi
2019-02-13 23:42 ` [PATCH v15 14/15] tracing: Add alternative synthetic event trace action " Tom Zanussi
2019-02-15 15:06 ` Masami Hiramatsu
2019-02-13 23:42 ` [PATCH v15 15/15] tracing: Add hist trigger action 'expected fail' " Tom Zanussi
2019-02-15 15:08 ` Masami Hiramatsu
2019-02-15 15:36 ` Steven Rostedt
2019-02-20 17:17 ` Steven Rostedt
2019-02-20 17:38 ` Tom Zanussi
2019-02-20 17:56 ` Steven Rostedt
2019-02-20 18:10 ` Tom Zanussi
2019-02-20 18:33 ` Steven Rostedt
2019-02-20 18:45 ` Tom Zanussi
2019-02-20 18:54 ` Steven Rostedt
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