AHAT - Android Heap Analysis Tool
Usage:
java -jar ahat.jar [OPTIONS] FILE
Launch an http server for viewing the given Android heap dump FILE.
OPTIONS:
-p <port>
Serve pages on the given port. Defaults to
7100.
--proguard-map FILE
Use the proguard map FILE to deobfuscate the heap dump.
--baseline FILE
Diff the heap dump against the given baseline heap dump FILE.
--baseline-proguard-map FILE
Use the proguard map FILE to deobfuscate the baseline heap dump.
--retained [strong | soft | finalizer | weak | phantom | unreachable]
The weakest reachability of instances to treat as retained.
Defaults to soft
TODO:
* Add a user guide.
* Dim 'image' and 'zygote' heap sizes slightly? Why do we even show these?
* Show site context and heap and class filter in "Objects" view?
* Add option to sort on more table columns as desired.
* Have a menu at the top of an object view with links to the sections?
* Include ahat version and hprof file in the menu at the top of the page?
* For HeapTable with single heap shown, the heap name isn't centered?
* Consistently document functions.
* Show version number with --version.
* Show somewhere where to send bugs.
* Include a link to /objects in the overview and menu?
* [low priority] by site allocations won't line up if the stack has been
truncated. Is there any way to manually line them up in that case?
Things to Test:
* That we can open a hprof without an 'app' heap and show a tabulation of
objects normally sorted by 'app' heap by default.
* Visit /objects without parameters and verify it doesn't throw an exception.
* Visit /objects with an invalid site, verify it doesn't throw an exception.
* That we can view the list of all objects in a reasonably short amount of
time.
* That we don't show the 'extra' column in the DominatedList if we are
showing all the instances.
* Instance.getDexCacheLocation
Known Issues:
* Line number decoding for allocations in proguarded classes.
Release History:
1.
11.
1 February,
2026
Strings page: improved performance, added pagination.
1.
11 February,
2026
Add Activity leaks page
Strings page now correctly shows string object allocation sizes
Strings page now respects --retained
1.
10 January,
2026
Move Bitmaps functionality to main menu (top bar).
Add Strings page to main menu to help find duplicate strings.
1.
9 December,
2025
Show sample path and incoming references to unreachable instances.
Add option to sort allocations table by various columns.
Add support for reading large heap dumps (>
2GB).
Add special handling for android.os.Message object instances.
1.
8 January
02,
2025
Show string values of byte[] instances.
Fix accounting for cleaned native registrations
Add option to download the contents of a byte[] as a file.
Show retained size in allocations view.
1.
7.
3 June
27,
2024
Add support to display bitmaps included in heapdump. To use this
functionality, collect the heapdump with `adb shell am dumpheap -b <fmt>`,
<fmt> can be `png`, `jpg` or `webp`.
1.
7.
2 March
2,
2022
Fix ahat parsing to allow leading whitespaces for comments.
Hide Value class constructor.
1.
7.
1 September
30,
2020
Fix issue parsing proguard maps with comments.
1.
7 August
8,
2019
Annotate binder services, tokens, and proxies.
Add option for viewing subclass instances of a class.
Recognize java.lang.ref.Finalizer as a finalizer reference.
Minor bug fixes and API improvements.
1.
6 July
24,
2018
Distinguish between soft/weak/phantom/etc references.
Annotate $classOverhead byte[] arrays with their class.
Show progress of heap dump processing.
Add --retained command line option to ahat.
Support heap dumps generated with HotSpotDiagnosticMXBean.
Updated public APIs for dominators computation, reachability and parser.
AhatInstance no longer implements DominatorsComputation.Node
Bug fixes.
1.
5 December
05,
2017
Distinguish between weakly reachable and unreachable instances.
Allow hex ids to be used for objects in query parameters.
Restore old presentation of sample paths from gc roots.
Fix bug in selection of sample paths from gc root.
Fix bug in proguard deobfuscation of stack frames.
Tighten up and document ahat public API.
1.
4 October
03,
2017
Give better error messages on failure to launch ahat.
Properly mark thread and non-default root objects as roots.
Improve startup performance, in some cases significantly.
Other miscellaneous bug fixes.
1.
3.
1 August
22,
2017
Don't include weak references in sample paths.
1.
3 July
25,
2017
Improve diffing of static and instance fields.
Improve startup performance by roughly
25%.
1.
2 May
26,
2017
Show registered native sizes of objects.
Simplify presentation of sample path from gc root.
1.
1 Feb
21,
2017
Show java.lang.ref.Reference referents as "unreachable" instead of null.
1.
0 Dec
20,
2016
Add support for diffing two heap dumps.
Remove native allocations view.
Remove outdated help page.
Significant refactoring of ahat internals.
0.
8 Oct
18,
2016
Show sample path from GC root with field names in place of dominator path.
0.
7 Aug
16,
2016
Launch ahat server before processing the heap dump.
Target Java
1.
7.
0.
6 Jun
21,
2016
Add support for proguard deobfuscation.
0.
5 Apr
19,
2016
Update perflib to perflib-
25.
0.
0 to improve processing performance.
0.
4 Feb
23,
2016
Annotate char[] objects with their string values.
Show registered native allocations for heap dumps that support it.
0.
3 Dec
15,
2015
Fix page loading performance by showing a limited number of entries by default.
Fix mismatch between overview and "roots" totals.
Annotate root objects and show their types.
Annotate references with their referents.
0.
2 Oct
20,
2015
Take into account 'count' and 'offset' when displaying strings.
0.
1ss Aug
04,
2015
Enable stack allocations code (using custom modified perflib).
Sort objects in 'objects/' with default sort.
0.
1-stacks Aug
03,
2015
Enable stack allocations code (using custom modified perflib).
0.
1 July
30,
2015
Initial Release
