792154 - [ARMv6] Profile java memory usage and GC pauses

Status: RESOLVED WONTFIX

(Firefox for Android Graveyard :: General, defect)

Description

[Kartikaya Gupta (email:[e-mail])]

This bug specifically tracks java memory allocations. We should reduce unnecessary memory allocations (including transient memory allocations) as much as possible to reduce fragmentation/thrashing in the dalvik heap. See bug 760229 as an example of where extra transient object allocations on the compositor code path was resulting in pauses during video playback. There are still quite a few transient object allocations left on that codepath that can be found using the ddms allocation tracker.

Comment 1

[Nicholas Nethercote [inactive]]

I just noticed on AWSY that at start-up explicit is ~22.95 MiB but resident is ~73.85 MiB.  That's a big difference.  I guess the Java memory is at least part of that difference?  Can we get the number of bytes allocated by Java?

Comment 2

[Kartikaya Gupta (email:[e-mail])]

I think most of the difference is libraries that are mapped into the process space. But yes, Java memory is some of that as well. I believe most of the java heap memory shows up under rss/other-files/dalvik-LinearAlloc. Java class libraries loaded into memory show up as rss/other-files/*.odex. There's a bunch of other non-trivial things under rss/other-files that I'm not sure about though, I think they may also be java heap memory but I don't know why they show up under different items.

Comment 3

[Kartikaya Gupta (email:[e-mail])]

Dropping support for ARMv6