History log of /dalvik/vm/LinearAlloc.h
Revision Date Author Comments
96516932f1557d8f48a8b2dbbb885af01a11ef6e 29-Oct-2009 Andy McFadden <fadden@android.com> Change the way breakpoints work.

This replaces the breakpoint mechanism with a more efficient approach.
We now insert breakpoint instructions into the bytecode stream instead of
maintaining a table. This requires mapping DEX files as private instead
of shared, which allows copy-on-write to work. mprotect() is used to
guard the pages against inadvertent writes.

Unused opcode EC is now OP_BREAKPOINT. It's not recognized by dexdump or
any interpreter except portdbg, but it can be encountered by the bytecode
verifier (the debugger can request breakpoints in unverified code).
Breakpoint changes are blocked while the verifier runs to avoid races.

This eliminates method->debugBreakpointCount, which is no longer needed.
(Also, it clashed with LinearAlloc's read-only mode.)

The deferred verification error mechanism was using a code-copying
approach to modify the bytecode stream. That has been changed to use
the same copy-on-write modification mechanism.

Also, normalized all PAGE_SIZE/PAGESIZE references to a single
SYSTEM_PAGE_SIZE define.

Simple Fibonacci computation test times (opal-eng):
JIT, no debugger: 10.6ms
Fast interp, no debugger: 36ms
Portable interp, no debugger: 43.8ms

ORIG debug interp, no breakpoints set: 458ms
ORIG debug interp, breakpoint set nearby: 697ms

NEW debug interp, no breakpoints set: 341ms
NEW debug interp, breakpoints set nearby: 341ms

Where "nearby" means there's a breakpoint in the method doing the
computation that isn't actually hit -- the VM had an optimization where
it flagged methods with breakpoints and skipped some of the processing
when possible.

The bottom line is that code should run noticeably faster while a
debugger is attached.
72e93344b4d1ffc71e9c832ec23de0657e5b04a5 13-Nov-2009 Jean-Baptiste Queru <jbq@google.com> eclair snapshot
cdacef5836df5fd69488d627e4d0db7cd3a86fae 31-Jul-2009 Bob Lee <crazybob@google.com> A sampling profiler for Dalvik.
7605a84a9a0a1764c1fb290d9c93e8114eaf620a 27-Jul-2009 Andy McFadden <fadden@android.com> Added dvmLinearAllocContains().
f6c387128427e121477c1b32ad35cdcaa5101ba3 04-Mar-2009 The Android Open Source Project <initial-contribution@android.com> auto import from //depot/cupcake/@135843
f72d5de56a522ac3be03873bdde26f23a5eeeb3c 04-Mar-2009 The Android Open Source Project <initial-contribution@android.com> auto import from //depot/cupcake/@135843
2ad60cfc28e14ee8f0bb038720836a4696c478ad 21-Oct-2008 The Android Open Source Project <initial-contribution@android.com> Initial Contribution