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

# gpg: Signature made Wed 12 Oct 2016 09:43:03 BST
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/tracing-pull-request:
  trace: Add missing execution mode of guest events
  trace: introduce a formal group name for trace events
  trace: pass trace-events to tracetool as a positional param
  trace: push reading of events up a level to tracetool main
  trace: rename _read_events to read_events
  trace: get rid of generated-events.h/generated-events.c
  trace: dynamically allocate event IDs at runtime
  trace: dynamically allocate trace_dstate in CPUState
  trace: provide mechanism for registering trace events
  trace: don't abort qemu if ftrace can't be initialized
  trace: emit name <-> ID mapping in simpletrace header
  trace: remove the TraceEventID and TraceEventVCPUID enums
  trace: give each trace event a named TraceEvent struct
  trace: break circular dependency in event-internal.h
  trace: remove duplicate control.h includes in generated-tracers.h
  trace: remove global 'uint16 dstate[]' array
  trace: remove some now unused functions
  trace: convert code to use event iterators
  trace: add trace event iterator APIs
  trace: move colo trace events to net/ sub-directory

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 35 insertions, 6 deletions

diff --git a/trace/simple.c b/trace/simple.c
index 2f09dafcbc..b263622fa9 100644
--- a/trace/simple.c
+++ b/trace/simple.c
@@ -17,14 +17,14 @@
 #include "trace/control.h"
 #include "trace/simple.h"
 
-/** Trace file header event ID */
-#define HEADER_EVENT_ID (~(uint64_t)0) /* avoids conflicting with TraceEventIDs */
+/** Trace file header event ID, picked to avoid conflict with real event IDs */
+#define HEADER_EVENT_ID (~(uint64_t)0)
 
 /** Trace file magic number */
 #define HEADER_MAGIC 0xf2b177cb0aa429b4ULL
 
 /** Trace file version number, bump if format changes */
-#define HEADER_VERSION 3
+#define HEADER_VERSION 4
 
 /** Records were dropped event ID */
 #define DROPPED_EVENT_ID (~(uint64_t)0 - 1)
@@ -56,9 +56,12 @@ static uint32_t trace_pid;
 static FILE *trace_fp;
 static char *trace_file_name;
 
+#define TRACE_RECORD_TYPE_MAPPING 0
+#define TRACE_RECORD_TYPE_EVENT   1
+
 /* * Trace buffer entry */
 typedef struct {
-    uint64_t event; /*   TraceEventID */
+    uint64_t event; /* event ID value */
     uint64_t timestamp_ns;
     uint32_t length;   /*    in bytes */
     uint32_t pid;
@@ -160,6 +163,7 @@ static gpointer writeout_thread(gpointer opaque)
     unsigned int idx = 0;
     int dropped_count;
     size_t unused __attribute__ ((unused));
+    uint64_t type = TRACE_RECORD_TYPE_EVENT;
 
     for (;;) {
         wait_for_trace_records_available();
@@ -174,10 +178,12 @@ static gpointer writeout_thread(gpointer opaque)
             } while (!g_atomic_int_compare_and_exchange(&dropped_events,
                                                         dropped_count, 0));
             dropped.rec.arguments[0] = dropped_count;
+            unused = fwrite(&type, sizeof(type), 1, trace_fp);
             unused = fwrite(&dropped.rec, dropped.rec.length, 1, trace_fp);
         }
 
         while (get_trace_record(idx, &recordptr)) {
+            unused = fwrite(&type, sizeof(type), 1, trace_fp);
             unused = fwrite(recordptr, recordptr->length, 1, trace_fp);
             writeout_idx += recordptr->length;
             free(recordptr); /* don't use g_free, can deadlock when traced */
@@ -202,7 +208,7 @@ void trace_record_write_str(TraceBufferRecord *rec, const char *s, uint32_t slen
     rec->rec_off = write_to_buffer(rec->rec_off, (void*)s, slen);
 }
 
-int trace_record_start(TraceBufferRecord *rec, TraceEventID event, size_t datasize)
+int trace_record_start(TraceBufferRecord *rec, uint32_t event, size_t datasize)
 {
     unsigned int idx, rec_off, old_idx, new_idx;
     uint32_t rec_len = sizeof(TraceRecord) + datasize;
@@ -273,6 +279,28 @@ void trace_record_finish(TraceBufferRecord *rec)
     }
 }
 
+static int st_write_event_mapping(void)
+{
+    uint64_t type = TRACE_RECORD_TYPE_MAPPING;
+    TraceEventIter iter;
+    TraceEvent *ev;
+
+    trace_event_iter_init(&iter, NULL);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
+        uint64_t id = trace_event_get_id(ev);
+        const char *name = trace_event_get_name(ev);
+        uint32_t len = strlen(name);
+        if (fwrite(&type, sizeof(type), 1, trace_fp) != 1 ||
+            fwrite(&id, sizeof(id), 1, trace_fp) != 1 ||
+            fwrite(&len, sizeof(len), 1, trace_fp) != 1 ||
+            fwrite(name, len, 1, trace_fp) != 1) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
 void st_set_trace_file_enabled(bool enable)
 {
     if (enable == !!trace_fp) {
@@ -297,7 +325,8 @@ void st_set_trace_file_enabled(bool enable)
             return;
         }
 
-        if (fwrite(&header, sizeof header, 1, trace_fp) != 1) {
+        if (fwrite(&header, sizeof header, 1, trace_fp) != 1 ||
+            st_write_event_mapping() < 0) {
             fclose(trace_fp);
             trace_fp = NULL;
             return;