@tdemin In other words: Slack does not use Google Cloud Messaging (or whatever it's currently called) to send notifications. Which is nice, but can technically have an impact on battery life because it will need to keep a connection open at all times. I said technically because on my phone it doesn't even show up as 1% battery use, so they must have done a great job at optimizing their battery usage.
GCM is just idle TCP, but made by Google for you because dumb application programmers can't get it right. And if you do it wrong, it drains battery.
Aside from connection setup, AFAIK an idle TCP connection with disabled keepalives uses 0 cpu cycles. 0 * number_of_apps == 0.
So the only thing that matters is how often you actually send something over that connection, and sending different events over different connections shouldn't really make a difference I suppose.
@Wolf480pl In practice you'll have keep-alive though. You want to receive push notifications after all. You'll also wake up occasionally to re-establish the connection in case it failed (network switch, timeout from the other side).
No idea what the effective impact is though. I'd rather sacrifice some battery life over using Google's service anyway.
>you'll have keep-alive though
hmm right I forgot about NATs.
> I'd rather sacrifice some battery life over using Google's service anyway.
@minus it does. It's just some OEM firmware likes to kill the apps in the way that's even worse than the one Google imposed. As in killing (not even suspending) EVERY app process that's not whitelisted on cheap Huawei phones, for instance (specifically had to whitelist Telegram on my relatives' phones).