Hi Masami, On Wed, 2018-09-19 at 08:54 +0900, Masami Hiramatsu wrote: > Hi Tom, > > On Tue, 18 Sep 2018 14:16:43 -0500 > Tom Zanussi <zanussi@xxxxxxxxxx> wrote: > > > Hi Masami, > > > > On Wed, 2018-09-19 at 03:54 +0900, Masami Hiramatsu wrote: > > > Hi Tom, > > > > > > On Mon, 10 Sep 2018 14:10:46 -0500 > > > Tom Zanussi <zanussi@xxxxxxxxxx> wrote: > > > > > > > From: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx> > > > > > > > > Add a 'trace(synthetic_event_name, params)' alternative to > > > > synthetic_event_name(params). > > > > > > > > Currently, the syntax used for generating synthetic events is > > > > to > > > > invoke synthetic_event_name(params) i.e. use the synthetic > > > > event > > > > name > > > > as a function call. > > > > > > > > Users requested a new form that more explicitly shows that the > > > > synthetic event is in effect being traced. In this version, a > > > > new > > > > 'trace()' keyword is used, and the synthetic event name is > > > > passed > > > > in > > > > as the first argument. > > > > > > Hmm, what is the advantage of adding this new form? > > > > > > > There's no real advantage other than user preference - Namhyung > > thought > > that since the event-name-as-function-call actions are all defined > > as > > ACTION_TRACE, there should also be an explicit 'trace' action. > > Ah, got it. Would this needs documentation and testcase update too? > The first part of the patch does contain the Documentation change to trace/histograms.txt. But I didn't do a testcase for it, will do that in the next iteration. > > > > So I added it as alternative syntax - the event-name-as-function- > > call > > form remains unchanged. > > > > By the way, I also have a patch implementing your alternative > > syntax > > change, where if you have only one handler, you can do away with > > the > > explicit action.handler form e.g. > > > > # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-ts0: > > \ > > onmax($wakeup_lat): \ > > save(next_prio,next_comm,prev_pid,prev_prio,prev_comm):snapshot > > () \ > > Hmm, in this case, I think comma-connected syntax will be clearer > when > the action is kicked. > > onmax($wakeup_lat).save(next_prio,next_comm,prev_pid,prev_prio,p > rev_comm),snapshot() > > any thought? > With the above I was trying to implement something close to your original suggestion of: <actions> onchange(<var>) So what I described was: <actions>:onchange(<var>) where <actions> would expand to action1[:action2:..] But as I mentioned both only make sense if you only have one onchange(<var>). Your new version: onchange(<var>).action1[,action2,..] is probably better as it would allow for multiple onchange<var> and/or other handlers. Thanks, Tom
