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 v6 02/15] tracing: Make hist trigger Documentation better reflect actions/handlers
Date: Thu, 11 Oct 2018 16:01:59 -0500 [thread overview]
Message-ID: <ed4a955416db3badc40d0a1c667be6f13d1085e2.1539288364.git.tom.zanussi@linux.intel.com> (raw)
In-Reply-To: <cover.1539288364.git.tom.zanussi@linux.intel.com>
In-Reply-To: <cover.1539288364.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 5ac724baea7d..0c265d04cbfb 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 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.
+When 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:[~2018-10-11 21:02 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 21:01 [PATCH v6 00/15] tracing: Hist trigger snapshot and onchange additions Tom Zanussi
2018-10-11 21:01 ` [PATCH v6 01/15] tracing: Refactor hist trigger action code Tom Zanussi
2018-10-23 5:09 ` Masami Hiramatsu
2018-10-23 21:18 ` Tom Zanussi
2018-10-11 21:01 ` Tom Zanussi [this message]
2018-10-11 21:02 ` [PATCH v6 03/15] tracing: Add hist trigger handler.action documentation to README Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 04/15] tracing: Split up onmatch action data Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 05/15] tracing: Generalize hist trigger onmax and save action Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 06/15] tracing: Add conditional snapshot Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 07/15] tracing: Move hist trigger key printing into a separate function Tom Zanussi
2018-10-23 14:37 ` Masami Hiramatsu
2018-10-23 21:24 ` Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 08/15] tracing: Add hist trigger snapshot() action Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 09/15] tracing: Add hist trigger snapshot() action Documentation Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 10/15] tracing: Add hist trigger snapshot() action test case Tom Zanussi
2018-10-23 15:03 ` Masami Hiramatsu
2018-10-23 21:32 ` Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 11/15] tracing: Add hist trigger onchange() handler Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 12/15] tracing: Add hist trigger onchange() handler Documentation Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 13/15] tracing: Add hist trigger onchange() handler test case Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 14/15] tracing: Add alternative synthetic event trace action syntax Tom Zanussi
2018-10-11 21:02 ` [PATCH v6 15/15] tracing: Add alternative synthetic event trace action test case Tom Zanussi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ed4a955416db3badc40d0a1c667be6f13d1085e2.1539288364.git.tom.zanussi@linux.intel.com \
--to=zanussi@kernel.org \
--cc=bigeasy@linutronix.de \
--cc=joel@joelfernandes.org \
--cc=julia@ni.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mhiramat@kernel.org \
--cc=namhyung@kernel.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=vedang.patel@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).