Re: [PATCH v3 1/6] perf tools: Derive trigger class from auxtrace_snapshot

["Wangnan (F)" <wangnan0@huawei.com>]

On 2016/4/17 19:50, Jiri Olsa wrote:
> On Fri, Apr 15, 2016 at 06:20:15PM +0000, Wang Nan wrote:
>> Create a new class named 'trigger' to model the state of a trigger and
>> implement auxtrace_snapshot with it.
>>
>> auxtrace_record__snapshot_started and auxtrace_snapshot_err are absorbed.
>>
>> 'trigger' defines 4 state transitioning functions ('on', 'released',
>> 'toggle' and 'colddown') and 2 state query function ('is_released') and
>> ('is_toggled'). The state 'ON' and 'OFF' take higher priority than
>> 'RELEASED' and 'TOGGLED'.  A trigger must be 'on' before 'enable' and
>> 'disable' take effect. A trigger can be colddown after being triggered.
> what's the COLDDOWN state for?

COLDDOWN is for auxtrace_record__snapshot_started. Once signal received,
auxtrace subsystem doesn't process following signal, until
record__read_auxtrace_snapshot finished successful. Mapping to trigger,
once the state of a trigger moves to 'TRIGGERED', there must be a state
neither RELEASED nor ERROR, which disallow triggering, but allow transiting
to RELEASED.


> could you please document all the transitions of this state machine
> in the change log and the trigger.h file?

Will do. Thank you.

> thanks,
> jirka