[Qemu-devel] [PULL 0/4] Tracing patches

[Qemu-devel] [PULL 0/4] Tracing patches

[Stefan Hajnoczi]

The following changes since commit 6801038bc52d61f81ac8a25fbe392f1bad982887:

  target-mips: fix wrong microMIPS opcode encoding (2012-11-15 14:48:16 +0100)

are available in the git repository at:

  git://github.com/stefanha/qemu.git tracing

for you to fetch changes up to e94c4c9287392e9c4de5e9cc3a0fa40da959ccb5:

  trace: Remove "info trace" from documents (2012-11-16 13:35:48 +0100)

----------------------------------------------------------------
Daniel P. Berrange (1):
      Avoid all systemtap reserved words

Gerd Hoffmann (1):
      trace: allow disabling events in events file

Liming Wang (1):
      trace: Remove "info trace" from documents

Stefan Hajnoczi (1):
      trace: document '-' syntax for disabling events

 docs/tracing.txt                    | 13 ++++---------
 hmp-commands.hx                     |  7 -------
 scripts/tracetool/backend/dtrace.py | 11 ++++++++++-
 trace/control.c                     |  9 ++++++++-
 4 files changed, 22 insertions(+), 18 deletions(-)

-- 
1.8.0

[Qemu-devel] [PATCH 1/4] Avoid all systemtap reserved words

[Stefan Hajnoczi]

From: "Daniel P. Berrange" <berrange@redhat.com>

Over time various systemtap reserved words have been blacklisted
in the trace backend generator. The list is not complete though,
so there is continued risk of problems in the future. Preempt
such problems by specifying the full list of systemtap keywords
listed in its parser as identified here:

  http://sourceware.org/ml/systemtap/2012-q4/msg00157.html

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 scripts/tracetool/backend/dtrace.py | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/scripts/tracetool/backend/dtrace.py b/scripts/tracetool/backend/dtrace.py
index 6be7047..23c43e2 100644
--- a/scripts/tracetool/backend/dtrace.py
+++ b/scripts/tracetool/backend/dtrace.py
@@ -73,6 +73,15 @@ def d(events):
         '};')
 
 
+# Technically 'self' is not used by systemtap yet, but
+# they recommended we keep it in the reserved list anyway
+RESERVED_WORDS = (
+    'break', 'catch', 'continue', 'delete', 'else', 'for',
+    'foreach', 'function', 'global', 'if', 'in', 'limit',
+    'long', 'next', 'probe', 'return', 'self', 'string',
+    'try', 'while'
+    )
+
 def stap(events):
     for e in events:
         # Define prototype for probe arguments
@@ -87,7 +96,7 @@ def stap(events):
         if len(e.args) > 0:
             for name in e.args.names():
                 # Append underscore to reserved keywords
-                if name in ('limit', 'in', 'next', 'self', 'function'):
+                if name in RESERVED_WORDS:
                     name += '_'
                 out('  %s = $arg%d;' % (name, i))
                 i += 1
-- 
1.8.0

[Qemu-devel] [PATCH 2/4] trace: allow disabling events in events file

[Stefan Hajnoczi]

From: Gerd Hoffmann <kraxel@redhat.com>

Disable trace events prefixed with a '-'.  Useful
to enable a group of tracepoints with exceptions,
like this:

  usb_xhci_port_*
  -usb_xhci_port_read

which will enable all xhci port tracepoints except reads.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 trace/control.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/trace/control.c b/trace/control.c
index 22d5863..be05efb 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -12,6 +12,8 @@
 
 void trace_backend_init_events(const char *fname)
 {
+    int ret;
+
     if (fname == NULL) {
         return;
     }
@@ -30,7 +32,12 @@ void trace_backend_init_events(const char *fname)
             if ('#' == line_buf[0]) { /* skip commented lines */
                 continue;
             }
-            if (!trace_event_set_state(line_buf, true)) {
+            if ('-' == line_buf[0]) {
+                ret = trace_event_set_state(line_buf+1, false);
+            } else {
+                ret = trace_event_set_state(line_buf, true);
+            }
+            if (!ret) {
                 fprintf(stderr,
                         "error: trace event '%s' does not exist\n", line_buf);
                 exit(1);
-- 
1.8.0

[Qemu-devel] [PATCH 3/4] trace: document '-' syntax for disabling events

[Stefan Hajnoczi]

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 docs/tracing.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/tracing.txt b/docs/tracing.txt
index c541133..7901409 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -139,6 +139,10 @@ having a common prefix in a batch. For example, virtio-blk trace events could
 be enabled using:
   trace-event virtio_blk_* on
 
+If a line in the "-trace events=<file>" file begins with a '-', the trace event
+will be disabled instead of enabled.  This is useful when a wildcard was used
+to enable an entire family of events but one noisy event needs to be disabled.
+
 == Trace backends ==
 
 The "tracetool" script automates tedious trace event code generation and also
-- 
1.8.0

[Qemu-devel] [PATCH 4/4] trace: Remove "info trace" from documents

[Stefan Hajnoczi]

From: Liming Wang <walimisdev@gmail.com>

commit 88affa1c monitor: remove unused do_info_trace

has removed "info trace" function from monitor, so remove it from documents.

Signed-off-by: Liming Wang <walimisdev@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 docs/tracing.txt | 9 ---------
 hmp-commands.hx  | 7 -------
 2 files changed, 16 deletions(-)

diff --git a/docs/tracing.txt b/docs/tracing.txt
index 7901409..453cc4a 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -189,15 +189,6 @@ records the char* pointer value instead of the string that is pointed to.
 
 ==== Monitor commands ====
 
-* info trace
-  Display the contents of trace buffer.  This command dumps the trace buffer
-  with simple formatting.  For full pretty-printing, use the simpletrace.py
-  script on a binary trace file.
-
-  The trace buffer is written into until full.  The full trace buffer is
-  flushed and emptied.  This means the 'info trace' will display few or no
-  entries if the buffer has just been flushed.
-
 * trace-file on|off|flush|set <path>
   Enable/disable/flush the trace file or set the trace file name.
 
diff --git a/hmp-commands.hx b/hmp-commands.hx
index b74ef75..010b8c9 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1573,13 +1573,6 @@ show roms
 @end table
 ETEXI
 
-#ifdef CONFIG_TRACE_SIMPLE
-STEXI
-@item info trace
-show contents of trace buffer
-ETEXI
-#endif
-
 STEXI
 @item info trace-events
 show available trace events and their state
-- 
1.8.0