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 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
