From: Tom Zanussi <tom.zanussi@linux.intel.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: rostedt@goodmis.org, tglx@linutronix.de, mhiramat@kernel.org,
vedang.patel@intel.com, linux-kernel@vger.kernel.org,
linux-rt-users@vger.kernel.org, kernel-team@lge.com
Subject: Re: [PATCH 16/32] tracing: Add variable support to hist triggers
Date: Wed, 19 Jul 2017 10:40:28 -0500 [thread overview]
Message-ID: <1500478828.23402.2.camel@tzanussi-mobl.amr.corp.intel.com> (raw)
In-Reply-To: <20170719010743.GA10107@sejong>
Hi Namhyung,
On Wed, 2017-07-19 at 10:07 +0900, Namhyung Kim wrote:
> Hi Tom,
>
> On Mon, Jun 26, 2017 at 05:49:17PM -0500, Tom Zanussi wrote:
> > Add support for saving the value of a current event's event field by
> > assigning it to a variable that can be read by a subsequent event.
> >
> > The basic syntax for saving a variable is to simply prefix a unique
> > variable name not corresponding to any keyword along with an '=' sign
> > to any event field.
> >
> > Both keys and values can be saved and retrieved in this way:
> >
> > # echo 'hist:keys=next_pid:vals=ts0=common_timestamp ...
> > # echo 'hist:key=timer_pid=common_pid ...'
> >
> > If a variable isn't a key variable or prefixed with 'vals=', the
> > associated event field will be saved in a variable but won't be summed
> > as a value:
> >
> > # echo 'hist:keys=next_pid:ts1=common_timestamp:...
> >
> > Multiple variables can be assigned at the same time:
> >
> > # echo 'hist:keys=pid:vals=ts0=common_timestamp,b=field1,field2 ...
> >
> > Multiple (or single) variables can also be assigned at the same time
> > using separate assignments:
> >
> > # echo 'hist:keys=pid:vals=ts0=common_timestamp:b=field1:c=field2 ...
>
> It seems the variable definition can be hard to read if multiple
> variables with expression are used. I think it'd be better to make it
> clear what's the key and the values by separating the variable
> definition. For example, the above example can be written as
>
> # echo 'hist:key=pid:val=ts0:ts0=$common_timestamp:b=field1:...'
>
> I know this is not a good example since the 'ts0' is a simple
> reference to the timestamp but it can be more complex..
>
> What do you think?
>
Yes, I think that makes sense - I was never a big fan of that syntax
anyway. I'll make that change in the next version.
Thanks,
Tom
next prev parent reply other threads:[~2017-07-19 15:40 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-26 22:49 [PATCH 00/32] tracing: Inter-event (e.g. latency) support Tom Zanussi
2017-06-26 22:49 ` [PATCH 01/32] tracing: Add hist_field_name() accessor Tom Zanussi
2017-07-13 6:49 ` Piotr Gregor
2017-07-13 14:41 ` Tom Zanussi
2017-07-14 2:19 ` Namhyung Kim
2017-06-26 22:49 ` [PATCH 02/32] tracing: Reimplement log2 Tom Zanussi
2017-07-14 2:33 ` Namhyung Kim
2017-07-14 16:13 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 03/32] ring-buffer: Add interface for setting absolute time stamps Tom Zanussi
2017-07-14 5:25 ` Namhyung Kim
2017-07-14 16:14 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 04/32] ring-buffer: Redefine the unimplemented RINGBUF_TIME_TIME_STAMP Tom Zanussi
2017-07-02 8:51 ` Joel Fernandes (Google)
2017-06-26 22:49 ` [PATCH 05/32] tracing: Give event triggers access to ring_buffer_event Tom Zanussi
2017-06-26 22:49 ` [PATCH 06/32] tracing: Add ring buffer event param to hist field functions Tom Zanussi
2017-06-26 22:49 ` [PATCH 07/32] tracing: Increase tracing map KEYS_MAX size Tom Zanussi
2017-06-26 22:49 ` [PATCH 08/32] tracing: Break out hist trigger assignment parsing Tom Zanussi
2017-06-26 22:49 ` [PATCH 09/32] tracing: Make traceprobe parsing code reusable Tom Zanussi
2017-06-26 22:49 ` [PATCH 10/32] tracing: Add NO_DISCARD event file flag Tom Zanussi
2017-06-26 22:49 ` [PATCH 11/32] tracing: Add post-trigger flag to hist trigger command Tom Zanussi
2017-06-26 22:49 ` [PATCH 12/32] tracing: Add hist trigger timestamp support Tom Zanussi
2017-07-17 6:00 ` Namhyung Kim
2017-07-17 16:57 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 13/32] tracing: Add per-element variable support to tracing_map Tom Zanussi
2017-06-26 22:49 ` [PATCH 14/32] tracing: Add hist_data member to hist_field Tom Zanussi
2017-06-26 22:49 ` [PATCH 15/32] tracing: Add usecs modifier for hist trigger timestamps Tom Zanussi
2017-06-26 22:49 ` [PATCH 16/32] tracing: Add variable support to hist triggers Tom Zanussi
2017-07-19 1:07 ` Namhyung Kim
2017-07-19 15:40 ` Tom Zanussi [this message]
2017-06-26 22:49 ` [PATCH 17/32] tracing: Account for variables in named trigger compatibility Tom Zanussi
2017-06-26 22:49 ` [PATCH 18/32] tracing: Add simple expression support to hist triggers Tom Zanussi
2017-07-21 2:02 ` Namhyung Kim
2017-07-21 16:29 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 19/32] tracing: Add variable reference handling " Tom Zanussi
2017-07-21 3:31 ` Namhyung Kim
2017-07-21 16:41 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 20/32] tracing: Add support for dynamic tracepoints Tom Zanussi
2017-06-26 22:49 ` [PATCH 21/32] tracing: Add hist trigger action hook Tom Zanussi
2017-06-26 22:49 ` [PATCH 22/32] tracing: Add support for 'synthetic' events Tom Zanussi
2017-07-23 12:00 ` Namhyung Kim
2017-07-24 16:11 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 23/32] tracing: Add 'onmatch' hist trigger action support Tom Zanussi
2017-07-23 15:12 ` Namhyung Kim
2017-07-24 16:17 ` Tom Zanussi
2017-07-26 2:40 ` Namhyung Kim
2017-07-26 16:38 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 24/32] tracing: Add 'onmax' " Tom Zanussi
2017-07-26 3:04 ` Namhyung Kim
2017-07-26 16:45 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 25/32] tracing: Allow whitespace to surround hist trigger filter Tom Zanussi
2017-06-26 22:49 ` [PATCH 26/32] tracing: Make duplicate count from tracing_map available Tom Zanussi
2017-06-26 22:49 ` [PATCH 27/32] tracing: Add cpu field for hist triggers Tom Zanussi
2017-06-26 22:49 ` [PATCH 28/32] tracing: Add hist trigger support for variable reference aliases Tom Zanussi
2017-06-26 22:49 ` [PATCH 29/32] tracing: Add 'last error' error facility for hist triggers Tom Zanussi
2017-07-26 4:39 ` Namhyung Kim
2017-07-26 16:47 ` Tom Zanussi
2017-06-26 22:49 ` [PATCH 30/32] tracing: Add inter-event hist trigger Documentation Tom Zanussi
2017-06-26 22:49 ` [PATCH 31/32] tracing: Make tracing_set_clock() non-static Tom Zanussi
2017-06-26 22:49 ` [PATCH 32/32] tracing: Add a clock attribute for hist triggers Tom Zanussi
2017-06-27 14:58 ` [PATCH 00/32] tracing: Inter-event (e.g. latency) support Steven Rostedt
2017-06-28 14:21 ` Masami Hiramatsu
2017-06-28 19:09 ` Tom Zanussi
2017-07-01 7:01 ` Joel Fernandes (Google)
2017-07-12 19:17 ` Tom Zanussi
2017-07-04 16:12 ` Sebastian Andrzej Siewior
2017-07-12 19:20 ` Tom Zanussi
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