Saving a Century a Day: Cut image loading time in half Tyrone Nicholas Software Engineer 10 October 2014
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Saving a Century a Day:Cut image loading time in half
Tyrone Nicholas
Software Engineer
10 October 2014
Demo
The Image Pipeline
JPG
BMP
BMP JPG
JPG
JPG
UI thread Non-UI threads
The bane of our existence
Android memory heapsDalvik Native
Native memory
Using native memory“Naïve native”
Native pools and streams
Native pools and streams
OutputStream
InputStream
Image Operation
Native Chunk
Native Chunk
Native ChunkNative
Chunk
Pool
Pinned purgeables
PurgeablesHowto
How purgeables work
Need memory?
Look for unpinned memory
Free it
Ashmem
• allocate
• pin
• unpin
How purgeables work
Allocate Draw Pin Decode
Stop drawing
Unpin
Draw cycle
Er, wait a minute…
How to do it (1)
How to do it (2)
Benefits
Risks
Reference counting in Java
SharedReference
CloseableReference
Using references
When?
When are you done with a bitmap?
Safe closing
Put byte buffers in native memory
Use purgeable bitmaps and pin them
Free your objects at the right time
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