[Qemu-devel] [Tracing] [PATCH 1/4] Move simple trace prototypes to header file

[Qemu-devel] [Tracing] [PATCH 1/4] Move simple trace prototypes to header file

[Stefan Hajnoczi]

Simple trace prototypes should not be in the tracetool code generator.
It is easier to modify and debug the code if they are in a regular C
header file.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
This patch is against the tracing branch:
http://repo.or.cz/w/qemu/stefanha.git/shortlog/refs/heads/tracing

 simpletrace.h |   37 +++++++++++++++++++++++++++++++++++++
 tracetool     |   22 +---------------------
 2 files changed, 38 insertions(+), 21 deletions(-)
 create mode 100644 simpletrace.h

diff --git a/simpletrace.h b/simpletrace.h
new file mode 100644
index 0000000..bec8d62
--- /dev/null
+++ b/simpletrace.h
@@ -0,0 +1,37 @@
+/*
+ * Simple trace backend
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef SIMPLETRACE_H
+#define SIMPLETRACE_H
+
+#include <stdbool.h>
+#include <stdio.h>
+
+typedef unsigned int TraceEventID;
+
+typedef struct {
+    const char *tp_name;
+    bool state;
+} TraceEvent;
+
+void trace0(TraceEventID event);
+void trace1(TraceEventID event, unsigned long x1);
+void trace2(TraceEventID event, unsigned long x1, unsigned long x2);
+void trace3(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3);
+void trace4(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long x4);
+void trace5(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long x4, unsigned long x5);
+void st_print_trace(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...));
+void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...));
+void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...));
+void st_flush_trace_buffer(void);
+void st_set_trace_file_enabled(bool enable);
+void change_trace_event_state(const char *tname, bool tstate);
+
+#endif /* SIMPLETRACE_H */
diff --git a/tracetool b/tracetool
index ac832af..4890e66 100755
--- a/tracetool
+++ b/tracetool
@@ -138,27 +138,7 @@ linetoc_end_nop()
 linetoh_begin_simple()
 {
     cat <<EOF
-#include <stdbool.h>
-
-typedef unsigned int TraceEventID;
-
-typedef struct {
-    const char *tp_name;
-    bool state;
-} TraceEvent;
-
-void trace0(TraceEventID event);
-void trace1(TraceEventID event, unsigned long x1);
-void trace2(TraceEventID event, unsigned long x1, unsigned long x2);
-void trace3(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3);
-void trace4(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long x4);
-void trace5(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long x4, unsigned long x5);
-void st_print_trace(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...));
-void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...));
-void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...));
-void st_flush_trace_buffer(void);
-void st_set_trace_file_enabled(bool enable);
-void change_trace_event_state(const char *tname, bool tstate);
+#include "simpletrace.h"
 EOF
 
     simple_event_num=0
-- 
1.7.1

[Qemu-devel] [Tracing] [PATCH 2/4] Add copyright and doc comments to simpletrace.py

[Stefan Hajnoczi]

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 simpletrace.py |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/simpletrace.py b/simpletrace.py
index 2271860..c951023 100755
--- a/simpletrace.py
+++ b/simpletrace.py
@@ -1,4 +1,14 @@
 #!/usr/bin/env python
+#
+# Pretty-printer for simple trace backend binary trace files
+#
+# Copyright IBM, Corp. 2010
+#
+# This work is licensed under the terms of the GNU GPL, version 2.  See
+# the COPYING file in the top-level directory.
+#
+# For help see docs/tracing.txt
+
 import sys
 import struct
 import re
@@ -8,7 +18,10 @@ trace_len = struct.calcsize(trace_fmt)
 event_re  = re.compile(r'(disable\s+)?([a-zA-Z0-9_]+)\(([^)]*)\)\s+"([^"]*)"')
 
 def parse_events(fobj):
+    """Parse a trace-events file."""
+
     def get_argnames(args):
+        """Extract argument names from a parameter list."""
         return tuple(arg.split()[-1].lstrip('*') for arg in args.split(','))
 
     events = {}
@@ -27,17 +40,21 @@ def parse_events(fobj):
     return events
 
 def read_record(fobj):
+    """Deserialize a trace record from a file."""
     s = fobj.read(trace_len)
     if len(s) != trace_len:
         return None
     return struct.unpack(trace_fmt, s)
 
 class Formatter(object):
+    """Trace record pretty-printer"""
+
     def __init__(self, events):
         self.events = events
         self.last_timestamp = None
 
     def format_record(self, rec):
+        """Return a string describing a given trace record."""
         if self.last_timestamp is None:
             self.last_timestamp = rec[1]
         delta_ns = rec[1] - self.last_timestamp
-- 
1.7.1

[Qemu-devel] [Tracing] [PATCH 3/4] Add a header to the trace file format

[Stefan Hajnoczi]

The trace file format needs a header so that future extension is
possible.  There is a version number that can be bumped when file format
changes are made.

There is still the issue of endianness and sizeof(long).  This patch
does not address those.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 simpletrace.c  |   17 ++++++++++++++++-
 simpletrace.py |   33 ++++++++++++++++++++++++++-------
 2 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/simpletrace.c b/simpletrace.c
index 71110b3..df21609 100644
--- a/simpletrace.c
+++ b/simpletrace.c
@@ -28,6 +28,17 @@ void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream,
                   getpid(), trace_file_enabled ? "on" : "off");
 }
 
+static bool write_header(FILE *fp)
+{
+    TraceRecord header = {
+        .event = -1UL, /* max avoids conflicting with TraceEventIDs */
+        .timestamp_ns = 0xf2b177cb0aa429b4, /* magic number */
+        .x1 = 0, /* bump this version number if file format changes */
+    };
+
+    return fwrite(&header, sizeof header, 1, fp) == 1;
+}
+
 static bool open_trace_file(void)
 {
     char *filename;
@@ -38,7 +49,11 @@ static bool open_trace_file(void)
 
     trace_fp = fopen(filename, "w");
     free(filename);
-    return trace_fp != NULL;
+    if (!trace_fp) {
+        return false;
+    }
+
+    return write_header(trace_fp);
 }
 
 static void flush_trace_file(void)
diff --git a/simpletrace.py b/simpletrace.py
index c951023..16ab2e7 100755
--- a/simpletrace.py
+++ b/simpletrace.py
@@ -13,10 +13,18 @@ import sys
 import struct
 import re
 
+header_event_id = 0xffffffffffffffff
+header_magic    = 0xf2b177cb0aa429b4
+header_version  = 0
+
 trace_fmt = 'LLLLLLL'
 trace_len = struct.calcsize(trace_fmt)
 event_re  = re.compile(r'(disable\s+)?([a-zA-Z0-9_]+)\(([^)]*)\)\s+"([^"]*)"')
 
+def err(msg):
+    sys.stderr.write(msg + '\n')
+    sys.exit(1)
+
 def parse_events(fobj):
     """Parse a trace-events file."""
 
@@ -46,6 +54,22 @@ def read_record(fobj):
         return None
     return struct.unpack(trace_fmt, s)
 
+def read_trace_file(fobj):
+    """Deserialize trace records from a file."""
+    header = read_record(fobj)
+    if header is None or \
+       header[0] != header_event_id or \
+       header[1] != header_magic or \
+       header[2] != header_version:
+        err('not a trace file or incompatible version')
+
+    while True:
+        rec = read_record(fobj)
+        if rec is None:
+            break
+
+        yield rec
+
 class Formatter(object):
     """Trace record pretty-printer"""
 
@@ -67,15 +91,10 @@ class Formatter(object):
         return ' '.join(fields)
 
 if len(sys.argv) != 3:
-    sys.stderr.write('usage: %s <trace-events> <trace-file>\n' % sys.argv[0])
-    sys.exit(1)
+    err('usage: %s <trace-events> <trace-file>' % sys.argv[0])
 
 events = parse_events(open(sys.argv[1], 'r'))
 f = open(sys.argv[2], 'rb')
 formatter = Formatter(events)
-while True:
-    rec = read_record(f)
-    if rec is None:
-        break
-
+for rec in read_trace_file(f):
     print formatter.format_record(rec)
-- 
1.7.1

[Qemu-devel] [Tracing] [PATCH 4/4] Disable posix_aio_process_queue by default

[Stefan Hajnoczi]

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 trace-events |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/trace-events b/trace-events
index 5304826..a50215f 100644
--- a/trace-events
+++ b/trace-events
@@ -63,4 +63,4 @@ disable virtio_blk_handle_write(void *req, unsigned long sector, unsigned long n
 
 # posix-aio-compat.c
 disable paio_submit(void *acb, void *opaque, unsigned long sector_num, unsigned long nb_sectors, unsigned long type) "acb %p opaque %p sector_num %lu nb_sectors %lu type %lu"
-posix_aio_process_queue(void *acb, void *opaque, int type, int ret, uint64_t blocking_duration) "acb %p opaque %p type %d ret %d blocking_duration %lx"
+disable posix_aio_process_queue(void *acb, void *opaque, int type, int ret, uint64_t blocking_duration) "acb %p opaque %p type %d ret %d blocking_duration %lx"
-- 
1.7.1