tree 3f9720425b2a024a5a54a0a71447dcea107229a8
parent 6508158f8388847f4cc3693e2cc1dbee6c2c7d18
author Andreas Gampe <agampe@google.com> 1425070144 -0800
committer Andreas Gampe <agampe@google.com> 1429155935 -0700

ART: Streaming trace mode

Add a streaming mode for tracing. Streaming uses a buffer of 16KB
and writes to the output when that buffer gets full. Streaming mode
can be enabled with -Xmethod-trace-stream and is currently not
exposed otherwise.

Add a python script that can parse the streaming format, which
simply contains strings for newly encountered threads and methods
inline, and create output that can be used with traceview.

Add Trace::Pause and Trace::Abort, which can pause and abort tracing.
Abort is different from Stop in that it does not write the data.

Add code to the zygote hooks JNI implementation that pauses tracing
before the fork, making sure that a child cannot clobber the parent's
data.

Add code to the zygote hooks JNI implementation that aborts old
tracing and starts new tracing in the child after the fork. Currently
base the output on the pid. This will not work on an unmodified
device, as the profiles directory is not generally writable, but
we do not have enough information at that point. Consider a scheme
that restarts tracing later.

Change-Id: I93c7bf87e35af582bdfdd3ecc7c52454514220dd