Tracing pull request

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Merge remote-tracking branch 'stefanha/tags/tracing-pull-request' into staging

Tracing pull request

# gpg: Signature made Mon 27 Jan 2014 14:51:09 GMT using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* stefanha/tags/tracing-pull-request:
  trace: fix simple trace "disable" keyword
  trace: add glib 2.32+ static GMutex support
  trace: [simple] Do not include "trace/simple.h" in generated tracer headers
  tracing: start trace processing thread in final child process

Message-id: 1390834386-23139-1-git-send-email-stefanha@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

scripts/tracetool/backend/simple.py

@@ -56,7 +56,7 @@ def c(events):
 
 
         out('',
-            '    TraceEvent *eventp = trace_event_id(%(event_id)s);',
+            '    TraceEvent *eventp = trace_event_id(%(event_enum)s);',
             '    bool _state = trace_event_get_state_dynamic(eventp);',
             '    if (!_state) {',
             '        return;',
@@ -65,6 +65,7 @@ def c(events):
             '    if (trace_record_start(&rec, %(event_id)s, %(size_str)s)) {',
             '        return; /* Trace Buffer Full, Event Dropped ! */',
             '    }',
+            event_enum = 'TRACE_' + event.name.upper(),
             event_id = num,
             size_str = sizestr,
             )
@@ -93,9 +94,6 @@ def c(events):
 
 
 def h(events):
-    out('#include "trace/simple.h"',
-        '')
-
     for event in events:
         out('void trace_%(name)s(%(args)s);',
             name = event.name,

trace/simple.c

@@ -19,6 +19,7 @@
 #include "qemu/timer.h"
 #include "trace.h"
 #include "trace/control.h"
+#include "trace/simple.h"
 
 /** Trace file header event ID */
 #define HEADER_EVENT_ID (~(uint64_t)0) /* avoids conflicting with TraceEventIDs */
@@ -39,7 +40,17 @@
  * Trace records are written out by a dedicated thread.  The thread waits for
  * records to become available, writes them out, and then waits again.
  */
+#if GLIB_CHECK_VERSION(2, 32, 0)
+static GMutex trace_lock;
+#define lock_trace_lock() g_mutex_lock(&trace_lock)
+#define unlock_trace_lock() g_mutex_unlock(&trace_lock)
+#define get_trace_lock_mutex() (&trace_lock)
+#else
 static GStaticMutex trace_lock = G_STATIC_MUTEX_INIT;
+#define lock_trace_lock() g_static_mutex_lock(&trace_lock)
+#define unlock_trace_lock() g_static_mutex_unlock(&trace_lock)
+#define get_trace_lock_mutex() g_static_mutex_get_mutex(&trace_lock)
+#endif
 
 /* g_cond_new() was deprecated in glib 2.31 but we still need to support it */
 #if GLIB_CHECK_VERSION(2, 31, 0)
@@ -139,27 +150,26 @@ static bool get_trace_record(unsigned int idx, TraceRecord **recordptr)
  */
 static void flush_trace_file(bool wait)
 {
-    g_static_mutex_lock(&trace_lock);
+    lock_trace_lock();
     trace_available = true;
     g_cond_signal(trace_available_cond);
 
     if (wait) {
-        g_cond_wait(trace_empty_cond, g_static_mutex_get_mutex(&trace_lock));
+        g_cond_wait(trace_empty_cond, get_trace_lock_mutex());
     }
 
-    g_static_mutex_unlock(&trace_lock);
+    unlock_trace_lock();
 }
 
 static void wait_for_trace_records_available(void)
 {
-    g_static_mutex_lock(&trace_lock);
+    lock_trace_lock();
     while (!(trace_available && trace_writeout_enabled)) {
         g_cond_signal(trace_empty_cond);
-        g_cond_wait(trace_available_cond,
+        g_cond_wait(trace_available_cond, get_trace_lock_mutex());
-                    g_static_mutex_get_mutex(&trace_lock));
     }
     trace_available = false;
-    g_static_mutex_unlock(&trace_lock);
+    unlock_trace_lock();
 }
 
 static gpointer writeout_thread(gpointer opaque)

vl.c

@@ -3879,9 +3879,11 @@ int main(int argc, char **argv, char **envp)
         qemu_set_log(mask);
     }
 
+    if (!is_daemonized()) {
         if (!trace_backend_init(trace_events, trace_file)) {
             exit(1);
         }
+    }
 
     /* If no data_dir is specified then try to find it relative to the
        executable path.  */
@@ -4379,6 +4381,12 @@ int main(int argc, char **argv, char **envp)
 
     os_setup_post();
 
+    if (is_daemonized()) {
+        if (!trace_backend_init(trace_events, trace_file)) {
+            exit(1);
+        }
+    }
+
     main_loop();
     bdrv_close_all();
     pause_all_vcpus();