Merge remote-tracking branch 'stefanha/tracing' into staging

* stefanha/tracing:
  vga: add trace event for ppm_save
  console: add some trace events
  maintainers: Add docs/tracing.txt to Tracing
  docs: correct ./configure line in tracing.txt
  trace: make trace_thread_create() use its function arg
  tracetool: Omit useless QEMU_*_ENABLED() check
  trace: Provide a per-event status define for conditional compilation

MAINTAINERS

@@ -548,6 +548,7 @@ Tracing
 M: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
 S: Maintained
 F: trace/
+F: docs/tracing.txt
 T: git://github.com/stefanha/qemu.git tracing
 
 Checkpatch

console.h

@@ -5,6 +5,7 @@
 #include "qdict.h"
 #include "notify.h"
 #include "monitor.h"
+#include "trace.h"
 
 /* keyboard/mouse support */
 
@@ -202,11 +203,13 @@ static inline DisplaySurface* qemu_create_displaysurface(DisplayState *ds, int w
 
 static inline DisplaySurface* qemu_resize_displaysurface(DisplayState *ds, int width, int height)
 {
+    trace_displaysurface_resize(ds, ds->surface, width, height);
     return ds->allocator->resize_displaysurface(ds->surface, width, height);
 }
 
 static inline void qemu_free_displaysurface(DisplayState *ds)
 {
+    trace_displaysurface_free(ds, ds->surface);
     ds->allocator->free_displaysurface(ds->surface);
 }
 

docs/tracing.txt

@@ -9,7 +9,7 @@ for debugging, profiling, and observing execution.
 
 1. Build with the 'simple' trace backend:
 
-    ./configure --trace-backend=simple
+    ./configure --enable-trace-backend=simple
     make
 
 2. Create a file with the events you want to trace:
@@ -98,12 +98,6 @@ respectively.  This ensures portability between 32- and 64-bit platforms.
 4. Name trace events after their function.  If there are multiple trace events
    in one function, append a unique distinguisher at the end of the name.
 
-5. If specific trace events are going to be called a huge number of times, this
-   might have a noticeable performance impact even when the trace events are
-   programmatically disabled. In this case you should declare the trace event
-   with the "disable" property, which will effectively disable it at compile
-   time (using the "nop" backend).
-
 == Generic interface and monitor commands ==
 
 You can programmatically query and control the dynamic state of trace events
@@ -234,3 +228,43 @@ probes:
                       --target-type system \
                       --target-arch x86_64 \
                       <trace-events >qemu.stp
+
+== Trace event properties ==
+
+Each event in the "trace-events" file can be prefixed with a space-separated
+list of zero or more of the following event properties.
+
+=== "disable" ===
+
+If a specific trace event is going to be invoked a huge number of times, this
+might have a noticeable performance impact even when the event is
+programmatically disabled.
+
+In this case you should declare such event with the "disable" property. This
+will effectively disable the event at compile time (by using the "nop" backend),
+thus having no performance impact at all on regular builds (i.e., unless you
+edit the "trace-events" file).
+
+In addition, there might be cases where relatively complex computations must be
+performed to generate values that are only used as arguments for a trace
+function. In these cases you can use the macro 'TRACE_${EVENT_NAME}_ENABLED' to
+guard such computations and avoid its compilation when the event is disabled:
+
+    #include "trace.h"  /* needed for trace event prototype */
+    
+    void *qemu_vmalloc(size_t size)
+    {
+        void *ptr;
+        size_t align = QEMU_VMALLOC_ALIGN;
+    
+        if (size < align) {
+            align = getpagesize();
+        }
+        ptr = qemu_memalign(align, size);
+        if (TRACE_QEMU_VMALLOC_ENABLED) { /* preprocessor macro */
+            void *complex;
+            /* some complex computations to produce the 'complex' value */
+            trace_qemu_vmalloc(size, ptr, complex);
+        }
+        return ptr;
+    }

hw/vga.c

@@ -30,6 +30,7 @@
 #include "pixel_ops.h"
 #include "qemu-timer.h"
 #include "xen.h"
+#include "trace.h"
 
 //#define DEBUG_VGA
 //#define DEBUG_VGA_MEM
@@ -2372,6 +2373,7 @@ int ppm_save(const char *filename, struct DisplaySurface *ds)
     int ret;
     char *linebuf, *pbuf;
 
+    trace_ppm_save(filename, ds);
     f = fopen(filename, "wb");
     if (!f)
         return -1;

scripts/tracetool

@@ -415,9 +415,7 @@ linetoh_dtrace()
     # Define an empty function for the trace event
     cat <<EOF
 static inline void trace_$name($args) {
-    if (QEMU_${nameupper}_ENABLED()) {
-        QEMU_${nameupper}($argnames);
-    }
+    QEMU_${nameupper}($argnames);
 }
 EOF
 }
@@ -519,7 +517,7 @@ linetostap_end_dtrace()
 # Process stdin by calling begin, line, and end functions for the backend
 convert()
 {
-    local begin process_line end str disable
+    local begin process_line end str name NAME enabled
     begin="lineto$1_begin_$backend"
     process_line="lineto$1_$backend"
     end="lineto$1_end_$backend"
@@ -534,8 +532,15 @@ convert()
         # Process the line.  The nop backend handles disabled lines.
         if has_property "$str" "disable"; then
             "lineto$1_nop" "$str"
+            enabled=0
         else
             "$process_line" "$str"
+            enabled=1
+        fi
+        if [ "$1" = "h" ]; then
+            name=$(get_name "$str")
+            NAME=$(echo $name | tr '[:lower:]' '[:upper:]')
+            echo "#define TRACE_${NAME}_ENABLED ${enabled}"
         fi
     done
 

trace-events

@@ -658,3 +658,10 @@ dma_aio_cancel(void *dbs) "dbs=%p"
 dma_complete(void *dbs, int ret, void *cb) "dbs=%p ret=%d cb=%p"
 dma_bdrv_cb(void *dbs, int ret) "dbs=%p ret=%d"
 dma_map_wait(void *dbs) "dbs=%p"
+
+# console.h
+displaysurface_free(void *display_state, void *display_surface) "state=%p surface=%p"
+displaysurface_resize(void *display_state, void *display_surface, int width, int height) "state=%p surface=%p %dx%d"
+
+# vga.c
+ppm_save(const char *filename, void *display_surface) "%s surface=%p"

trace/simple.c

@@ -363,7 +363,7 @@ static GThread *trace_thread_create(GThreadFunc fn)
     sigfillset(&set);
     pthread_sigmask(SIG_SETMASK, &set, &oldset);
 #endif
-    thread = g_thread_create(writeout_thread, NULL, FALSE, NULL);
+    thread = g_thread_create(fn, NULL, FALSE, NULL);
 #ifndef _WIN32
     pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 #endif