Comment 7 for bug 1350598

I mentioned this to Marcus via irc yesterday and I think it is useful context (leaving out parts that John already mentioned):

"07:48 <marcustomlinson> so question: when we have that slow boot, what screen is everyone left on to wait
07:48 <marcustomlinson> blank? spinning ubuntu icom
07:49 <jdstrand> blank
07:49 <jdstrand> it is after the image is flashed and is comin up. there is no feedback
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07:54 <marcustomlinson> I think we can hold back on Michi's MP as worst case scenario
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07:55 <jdstrand> basically, the way it is all framed is that these sorts of updates should typically only happen when jumping base releases, since a policy recompile has to happen anyway
07:55 <jdstrand> so, vivid to xenial
07:55 <jdstrand> I can push this change into xenial no problem
07:55 <jdstrand> then whenever that ota comes out, it is there
07:55 <marcustomlinson> ah ok
07:55 <jdstrand> but we try to reduce the pain of interim updates
07:56 <jdstrand> we don't want every ota to have a slow boot
07:56 <marcustomlinson> do you see these updates as that rarely required?
07:56 <jdstrand> but it is possible to batch them or make a decision that this is important enough to make everyone wait
07:56 <jdstrand> yes
07:56 <jdstrand> we've maybe only had to recompile all policy once since vivid base
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07:57 <jdstrand> we do make other profile changes, but that might be in say, the calendar policy
07:57 <jdstrand> the calendar policy is only used by a few apps-- so no big deal
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07:57 <jdstrand> but something that affects all scopes is a different thing
07:58 <marcustomlinson> ok, thanks for the info!
07:58 <jdstrand> np
07:58 <jdstrand> if you are interested in the nitty gritty details, do see the apparmor bug
07:58 <marcustomlinson> will do
07:59 <jdstrand> it should be noted that since that bug has been filed, we have made many policy compile improvements
07:59 <jdstrand> but the problem can never go away
07:59 <jdstrand> it was at 2.5 seconds
07:59 <jdstrand> per profile
08:00 <jdstrand> I think we are under 1.5 now
08:00 <marcustomlinson> nice
08:00 <jdstrand> but even if we got it to 1, if you have 200 apps installed, that is almost 3.5 minutes of waiting
08:00 <marcustomlinson> like I said, I think we actually "make this go away" by showing people a progress bar or something
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08:00 <jdstrand> I agree. the pieces are there on click. something different would have to be done for snappy
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In a nutshell, John has done some amazing stuff already with policy compile times, and more improvements will come and in fact, we are already considerably faster than IOS (aiui) and Android's app update process after reboot even with full policy recompiles, but the problem is we don't give people any feedback what is happening (I discuss ways for unity/the platform to deal with this above). Do keep in mind that because of the sheer volume of apps that can be installed on a phone and because the compile time won't ever be '0', we will always want to be judicious about policy updates that affect all apps-- that's where visual feedback can help.