gltrace: Add support for tracing running applications.
Currently, to activate OpenGL tracing, an application has to be
start with --opengl-trace option (or have a debug prop set).
This CL adds support for tracing an application which may already
be running. This is implemented as follows:
- DDMS initiates a JDWP message to the VM indicating that
opengl traces be enabled.
- When that message is received, a flag is set that indicates
that tracing should be enabled.
- The trace flag is checked during every eglSwap() operation,
and if it finds that tracing should be active and it isn't,
then it starts the tracing component.
Change-Id: I3347fe89fc06c7404d7aa9360f4b21e5bf36ebcb
diff --git a/opengl/libs/GLES_trace/DESIGN.txt b/opengl/libs/GLES_trace/DESIGN.txt
index a189e1d..72a2e15 100644
--- a/opengl/libs/GLES_trace/DESIGN.txt
+++ b/opengl/libs/GLES_trace/DESIGN.txt
@@ -9,9 +9,6 @@
control whether tracing should be enabled for a certain process. If tracing is enabled, this
calls GLTrace_start() to start the trace server.
- Note that initEglTraceLevel() is also called from early_egl_init(), but that happens in the
- context of the zygote, so that invocation has no effect.
-
egl_display_t::initialize() then calls setGLHooksThreadSpecific() where we set the thread
specific gl_hooks structure to point to the trace implementation. From this point on, every
GLES call is redirected to the trace implementation.
@@ -30,6 +27,37 @@
to explore if a more graceful method of stopping the application, or detaching tracing from the
application is required.
+
+Enabling tracing while the application is running:
+
+ In order to allow tracing of an already running application, we allow DdmServer to enable
+ OpenGL tracing. In such a case, the application already has its GL hooks set up to point to the
+ real GL implementation, and we need to switch them to point to the trace implementation.
+
+ This is achieved by checking whether tracing should be enabled at every eglSwap call.
+ (Note: We were already checking for tracing at every eglSwap, the only change now is that
+ the tracing could actually be ON/OFF at runtime - earlier it was set once and never changed).
+
+ If eglSwap detects that tracing should be enabled now, then it performs the following steps:
+ - switch the gl hooks to point to the trace implementation.
+ - call trace eglMakeCurrent to indicate that there is now a new context that is current.
+ - continue on with tracing the eglSwap call.
+ This switches the hooks to point to the trace implementation only for the current context.
+ But the other contexts have their gl hooks updated when they perform eglMakeCurrent.
+
+ The GLTrace version of eglMakeCurrent now has to be updated to allow switching to a context
+ it may not know of. In such a case, it creates a context matching the version that it is now
+ switching to.
+
+Disabling tracing:
+
+ We disable tracing under two conditions:
+ - stop tracing request from DdmServer
+ - gltrace transport gets disconnected from the host.
+ In either case, both actions simply disable the tracing flag. The current context gets its
+ gl hooks restored in the next eglSwap, and the other traced contexts get their gl hooks
+ restored when they perform a eglMakeCurrent.
+
Code Structure:
glestrace.h declares all the hooks exposed by libglestrace. These are used by EGL/egl.cpp and
diff --git a/opengl/libs/GLES_trace/src/gltrace_eglapi.cpp b/opengl/libs/GLES_trace/src/gltrace_eglapi.cpp
index 9698bf9..512d562 100644
--- a/opengl/libs/GLES_trace/src/gltrace_eglapi.cpp
+++ b/opengl/libs/GLES_trace/src/gltrace_eglapi.cpp
@@ -33,6 +33,9 @@
using gltrace::GLTraceContext;
using gltrace::TCPStream;
+static pthread_mutex_t sGlTraceStateLock = PTHREAD_MUTEX_INITIALIZER;
+
+static int sGlTraceInProgress;
static GLTraceState *sGLTraceState;
static pthread_t sReceiveThreadId;
@@ -105,33 +108,66 @@
return NULL;
}
-void GLTrace_start() {
- char udsName[PROPERTY_VALUE_MAX];
+/**
+ * Starts Trace Server and waits for connection from the host.
+ * Returns -1 in case of connection error, 0 otherwise.
+ */
+int GLTrace_start() {
+ int status = 0;
+ int clientSocket = -1;
+ TCPStream *stream = NULL;
- property_get("debug.egl.debug_portname", udsName, "gltrace");
- int clientSocket = gltrace::acceptClientConnection(udsName);
- if (clientSocket < 0) {
- ALOGE("Error creating GLTrace server socket. Quitting application.");
- exit(-1);
+ pthread_mutex_lock(&sGlTraceStateLock);
+
+ if (sGlTraceInProgress) {
+ goto done;
}
+ char udsName[PROPERTY_VALUE_MAX];
+ property_get("debug.egl.debug_portname", udsName, "gltrace");
+ clientSocket = gltrace::acceptClientConnection(udsName);
+ if (clientSocket < 0) {
+ ALOGE("Error creating GLTrace server socket. Tracing disabled.");
+ status = -1;
+ goto done;
+ }
+
+ sGlTraceInProgress = 1;
+
// create communication channel to the host
- TCPStream *stream = new TCPStream(clientSocket);
+ stream = new TCPStream(clientSocket);
// initialize tracing state
sGLTraceState = new GLTraceState(stream);
pthread_create(&sReceiveThreadId, NULL, commandReceiveTask, sGLTraceState);
+
+done:
+ pthread_mutex_unlock(&sGlTraceStateLock);
+ return status;
}
void GLTrace_stop() {
- delete sGLTraceState;
- sGLTraceState = NULL;
+ pthread_mutex_lock(&sGlTraceStateLock);
+
+ if (sGlTraceInProgress) {
+ sGlTraceInProgress = 0;
+ delete sGLTraceState;
+ sGLTraceState = NULL;
+ }
+
+ pthread_mutex_unlock(&sGlTraceStateLock);
}
void GLTrace_eglCreateContext(int version, EGLContext c) {
+ pthread_mutex_lock(&sGlTraceStateLock);
+ GLTraceState *state = sGLTraceState;
+ pthread_mutex_unlock(&sGlTraceStateLock);
+
+ if (state == NULL) return;
+
// update trace state for new EGL context
- GLTraceContext *traceContext = sGLTraceState->createTraceContext(version, c);
+ GLTraceContext *traceContext = state->createTraceContext(version, c);
gltrace::setupTraceContextThreadSpecific(traceContext);
// trace command through to the host
@@ -139,8 +175,19 @@
}
void GLTrace_eglMakeCurrent(const unsigned version, gl_hooks_t *hooks, EGLContext c) {
+ pthread_mutex_lock(&sGlTraceStateLock);
+ GLTraceState *state = sGLTraceState;
+ pthread_mutex_unlock(&sGlTraceStateLock);
+
+ if (state == NULL) return;
+
// setup per context state
- GLTraceContext *traceContext = sGLTraceState->getTraceContext(c);
+ GLTraceContext *traceContext = state->getTraceContext(c);
+ if (traceContext == NULL) {
+ GLTrace_eglCreateContext(version, c);
+ traceContext = state->getTraceContext(c);
+ }
+
traceContext->hooks = hooks;
gltrace::setupTraceContextThreadSpecific(traceContext);