I was reading the Ars article about Tarako, which mentioned how input events 
would pile up and cause long freezes.

This bug was supposed to mitigate that problem: 
https://bugzilla.mozilla.org/show_bug.cgi?id=971633

Eric said that change only discards events 1 second old, which might be too 
conservative.

Should we do some testing to see if lowering that would improve the situation 
at all? Maybe we can optimize a little bit more and strike the right balance 
where the user can't input enough events to cause *super* long freezes. Just 
little reasonable freezes :)


IRC notes below.


10:01 < dietrich> from Ars: "If you enter too many commands at once, it will 
freeze up for long periods at a time."
10:03 < erahm> dietrich: yeah, in theory it discards events after a second 
delay I think. There's some jankiness where we needed to pair key down and key 
up events though
10:43 < dietrich> erahm: i wonder if a second is too long
10:44 < dietrich> erahm: wdym about the key up/down?
10:45 < erahm> dietrich: yeah it was a bit conservative. we need to make sure 
we don't chuck key up events (or touch up whatever) that corresponded to key 
down events
10:46 < dietrich> oh gotcha
10:48 < erahm> dietrich: something like 125ms is the human threshold for 
detecting jank, so 1s seems too conservative, but given that the tarako is 
inherently slow I think we'd just end up discarding 
               way more events than the user would expect. We really need some 
sort of "unresponsive app" notification that kicks in instead
10:48 < dietrich> eww
10:48 < erahm> that's life w/ zram thrashing :(
10:48 < dietrich> or do you mean lower level notification, not UI
10:49 < dietrich> discarding more events might be ok though
10:49 < dietrich> would really need to test
10:50 < erahm> It's should probably be both, it's a better experience to see 
some indication that we're thinking about doing something than tapping a bunch 
and then have apps stutter in and out of 
               existence
11:00 < dietrich> erahm: what's the original bug #?
11:01 < erahm> dietrich: bug 971633
11:01 < freonbot> Bug http://bugzil.la/971633 erahm, RESOLVED, FIXED, --, 
[b2g][tarako] Filter out stale input events
11:07 < erahm> dietrich: it would appear that code got moved though, and we're 
probably not filtering touch events anymore
11:10 < erahm> dietrich: ah ok, it just got moved over, it should still work. 
Touch filtering is in here: 
http://hg.mozilla.org/mozilla-central/file/935836821a9d/widget/gonk/GeckoTouchDispatcher.cpp
11:10 < freonbot> [ mozilla-central: 
widget/gonk/GeckoTouchDispatcher.cpp@935836821a9d ] - hg.mozilla.org
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