Pull request

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

Pull request

# gpg: Signature made Mon 12 Jul 2021 17:49:46 BST
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha-gitlab/tags/tracing-pull-request:
  trace, lttng: require .pc files
  trace/simple: add st_init_group
  trace/simple: pass iter to st_write_event_mapping
  trace: add trace_event_iter_init_group
  trace: iter init tweaks
  qemu-trace-stap: changing SYSTEMTAP_TAPSET considered harmful.

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

configure

@@ -3606,21 +3606,8 @@ fi
 ##########################################
 # For 'ust' backend, test if ust headers are present
 if have_backend "ust"; then
-  cat > $TMPC << EOF
-#include <lttng/tracepoint.h>
-int main(void) { return 0; }
-EOF
-  if compile_prog "" "-Wl,--no-as-needed -ldl" ; then
   if $pkg_config lttng-ust --exists; then
     lttng_ust_libs=$($pkg_config --libs lttng-ust)
-    else
-      lttng_ust_libs="-llttng-ust -ldl"
-    fi
-    if $pkg_config liburcu-bp --exists; then
-      urcu_bp_libs=$($pkg_config --libs liburcu-bp)
-    else
-      urcu_bp_libs="-lurcu-bp"
-    fi
   else
     error_exit "Trace backend 'ust' missing lttng-ust header files"
   fi
@@ -4773,7 +4760,6 @@ fi
 if have_backend "ust"; then
   echo "CONFIG_TRACE_UST=y" >> $config_host_mak
   echo "LTTNG_UST_LIBS=$lttng_ust_libs" >> $config_host_mak
-  echo "URCU_BP_LIBS=$urcu_bp_libs" >> $config_host_mak
 fi
 if have_backend "dtrace"; then
   echo "CONFIG_TRACE_DTRACE=y" >> $config_host_mak

meson.build

@@ -319,10 +319,6 @@ lttng = not_found
 if 'CONFIG_TRACE_UST' in config_host
   lttng = declare_dependency(link_args: config_host['LTTNG_UST_LIBS'].split())
 endif
-urcubp = not_found
-if 'CONFIG_TRACE_UST' in config_host
-  urcubp = declare_dependency(link_args: config_host['URCU_BP_LIBS'].split())
-endif
 pixman = not_found
 if have_system or have_tools
   pixman = dependency('pixman-1', required: have_system, version:'>=0.21.8',

monitor/misc.c

@@ -1804,7 +1804,7 @@ void info_trace_events_completion(ReadLineState *rs, int nb_args, const char *st
         TraceEventIter iter;
         TraceEvent *ev;
         char *pattern = g_strdup_printf("%s*", str);
-        trace_event_iter_init(&iter, pattern);
+        trace_event_iter_init_pattern(&iter, pattern);
         while ((ev = trace_event_iter_next(&iter)) != NULL) {
             readline_add_completion(rs, trace_event_get_name(ev));
         }
@@ -1822,7 +1822,7 @@ void trace_event_completion(ReadLineState *rs, int nb_args, const char *str)
         TraceEventIter iter;
         TraceEvent *ev;
         char *pattern = g_strdup_printf("%s*", str);
-        trace_event_iter_init(&iter, pattern);
+        trace_event_iter_init_pattern(&iter, pattern);
         while ((ev = trace_event_iter_next(&iter)) != NULL) {
             readline_add_completion(rs, trace_event_get_name(ev));
         }

scripts/qemu-trace-stap

@@ -55,11 +55,6 @@ def tapset_dir(binary):
     return os.path.realpath(tapset)
 
 
-def tapset_env(tapset_dir):
-    tenv = copy.copy(os.environ)
-    tenv["SYSTEMTAP_TAPSET"] = tapset_dir
-    return tenv
-
 def cmd_run(args):
     prefix = probe_prefix(args.binary)
     tapsets = tapset_dir(args.binary)
@@ -81,11 +76,11 @@ def cmd_run(args):
 
     # We request an 8MB buffer, since the stap default 1MB buffer
     # can be easily overflowed by frequently firing QEMU traces
-    stapargs = ["stap", "-s", "8"]
+    stapargs = ["stap", "-s", "8", "-I", tapsets ]
     if args.pid is not None:
         stapargs.extend(["-x", args.pid])
     stapargs.extend(["-e", script])
-    subprocess.call(stapargs, env=tapset_env(tapsets))
+    subprocess.call(stapargs)
 
 
 def cmd_list(args):
@@ -101,10 +96,9 @@ def cmd_list(args):
 
         if verbose:
             print("Listing probes with name '%s'" % script)
-        proc = subprocess.Popen(["stap", "-l", script],
+        proc = subprocess.Popen(["stap", "-I", tapsets, "-l", script],
                                 stdout=subprocess.PIPE,
-                                universal_newlines=True,
+                                universal_newlines=True)
-                                env=tapset_env(tapsets))
         out, err = proc.communicate()
         if proc.returncode != 0:
             print("No probes found, are the tapsets installed in %s" % tapset_dir(args.binary))

trace/control-target.c

@@ -127,7 +127,7 @@ void trace_init_vcpu(CPUState *vcpu)
 {
     TraceEventIter iter;
     TraceEvent *ev;
-    trace_event_iter_init(&iter, NULL);
+    trace_event_iter_init_all(&iter);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         if (trace_event_is_vcpu(ev) &&
             trace_event_get_state_static(ev) &&

trace/control.c

@@ -82,6 +82,10 @@ void trace_event_register_group(TraceEvent **events)
     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
     event_groups[nevent_groups].events = events;
     nevent_groups++;
+
+#ifdef CONFIG_TRACE_SIMPLE
+    st_init_group(nevent_groups - 1);
+#endif
 }
 
 
@@ -91,7 +95,7 @@ TraceEvent *trace_event_name(const char *name)
 
     TraceEventIter iter;
     TraceEvent *ev;
-    trace_event_iter_init(&iter, NULL);
+    trace_event_iter_init_all(&iter);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         if (strcmp(trace_event_get_name(ev), name) == 0) {
             return ev;
@@ -100,27 +104,46 @@ TraceEvent *trace_event_name(const char *name)
     return NULL;
 }
 
-void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
+void trace_event_iter_init_all(TraceEventIter *iter)
 {
     iter->event = 0;
     iter->group = 0;
+    iter->group_id = -1;
+    iter->pattern = NULL;
+}
+
+void trace_event_iter_init_pattern(TraceEventIter *iter, const char *pattern)
+{
+    trace_event_iter_init_all(iter);
     iter->pattern = pattern;
 }
 
+void trace_event_iter_init_group(TraceEventIter *iter, size_t group_id)
+{
+    trace_event_iter_init_all(iter);
+    iter->group_id = group_id;
+}
+
 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 {
     while (iter->group < nevent_groups &&
            event_groups[iter->group].events[iter->event] != NULL) {
         TraceEvent *ev = event_groups[iter->group].events[iter->event];
+        size_t group = iter->group;
         iter->event++;
         if (event_groups[iter->group].events[iter->event] == NULL) {
             iter->event = 0;
             iter->group++;
         }
-        if (!iter->pattern ||
+        if (iter->pattern &&
-            g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) {
+            !g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) {
-            return ev;
+            continue;
         }
+        if (iter->group_id != -1 &&
+            iter->group_id != group) {
+            continue;
+        }
+        return ev;
     }
 
     return NULL;
@@ -130,7 +153,7 @@ void trace_list_events(FILE *f)
 {
     TraceEventIter iter;
     TraceEvent *ev;
-    trace_event_iter_init(&iter, NULL);
+    trace_event_iter_init_all(&iter);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         fprintf(f, "%s\n", trace_event_get_name(ev));
     }
@@ -150,7 +173,7 @@ static void do_trace_enable_events(const char *line_buf)
     TraceEvent *ev;
     bool is_pattern = trace_event_is_pattern(line_ptr);
 
-    trace_event_iter_init(&iter, line_ptr);
+    trace_event_iter_init_pattern(&iter, line_ptr);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         if (!trace_event_get_state_static(ev)) {
             if (!is_pattern) {
@@ -256,7 +279,7 @@ void trace_fini_vcpu(CPUState *vcpu)
 
     trace_guest_cpu_exit(vcpu);
 
-    trace_event_iter_init(&iter, NULL);
+    trace_event_iter_init_all(&iter);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         if (trace_event_is_vcpu(ev) &&
             trace_event_get_state_static(ev) &&

trace/control.h

@@ -13,22 +13,44 @@
 #include "event-internal.h"
 
 typedef struct TraceEventIter {
+    /* iter state */
     size_t event;
     size_t group;
+    /* filter conditions */
+    size_t group_id;
     const char *pattern;
 } TraceEventIter;
 
 
 /**
- * trace_event_iter_init:
+ * trace_event_iter_init_all:
  * @iter: the event iterator struct
- * @pattern: optional pattern to filter events on name
  *
  * Initialize the event iterator struct @iter,
- * optionally using @pattern to filter out events
+ * for all events.
+ */
+void trace_event_iter_init_all(TraceEventIter *iter);
+
+/**
+ * trace_event_iter_init_pattern:
+ * @iter: the event iterator struct
+ * @pattern: pattern to filter events on name
+ *
+ * Initialize the event iterator struct @iter,
+ * using @pattern to filter out events
  * with non-matching names.
  */
-void trace_event_iter_init(TraceEventIter *iter, const char *pattern);
+void trace_event_iter_init_pattern(TraceEventIter *iter, const char *pattern);
+
+/**
+ * trace_event_iter_init_group:
+ * @iter: the event iterator struct
+ * @group_id: group_id to filter events by group.
+ *
+ * Initialize the event iterator struct @iter,
+ * using @group_id to filter for events in the group.
+ */
+void trace_event_iter_init_group(TraceEventIter *iter, size_t group_id);
 
 /**
  * trace_event_iter_next:

trace/meson.build

@@ -26,7 +26,7 @@ foreach dir : [ '.' ] + trace_events_subdirs
                                 input: trace_events_file,
                                 command: [ tracetool, group, '--format=ust-events-h', '@INPUT@', '@OUTPUT@' ],
                                 depend_files: tracetool_depends)
-    trace_ss.add(trace_ust_h, lttng, urcubp)
+    trace_ss.add(trace_ust_h, lttng)
     genh += trace_ust_h
   endif
   trace_ss.add(trace_h, trace_c)

trace/qmp.c

@@ -55,7 +55,7 @@ static bool check_events(bool has_vcpu, bool ignore_unavailable, bool is_pattern
         /* error for unavailable events */
         TraceEventIter iter;
         TraceEvent *ev;
-        trace_event_iter_init(&iter, name);
+        trace_event_iter_init_pattern(&iter, name);
         while ((ev = trace_event_iter_next(&iter)) != NULL) {
             if (!ignore_unavailable && !trace_event_get_state_static(ev)) {
                 error_setg(errp, "event \"%s\" is disabled", trace_event_get_name(ev));
@@ -90,7 +90,7 @@ TraceEventInfoList *qmp_trace_event_get_state(const char *name,
     }
 
     /* Get states (all errors checked above) */
-    trace_event_iter_init(&iter, name);
+    trace_event_iter_init_pattern(&iter, name);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         TraceEventInfo *value;
         bool is_vcpu = trace_event_is_vcpu(ev);
@@ -153,7 +153,7 @@ void qmp_trace_event_set_state(const char *name, bool enable,
     }
 
     /* Apply changes (all errors checked above) */
-    trace_event_iter_init(&iter, name);
+    trace_event_iter_init_pattern(&iter, name);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         if (!trace_event_get_state_static(ev) ||
             (has_vcpu && !trace_event_is_vcpu(ev))) {

trace/simple.c

@@ -280,14 +280,12 @@ void trace_record_finish(TraceBufferRecord *rec)
     }
 }
 
-static int st_write_event_mapping(void)
+static int st_write_event_mapping(TraceEventIter *iter)
 {
     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) {
-    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);
@@ -309,6 +307,7 @@ static int st_write_event_mapping(void)
  */
 bool st_set_trace_file_enabled(bool enable)
 {
+    TraceEventIter iter;
     bool was_enabled = trace_fp;
 
     if (enable == !!trace_fp) {
@@ -333,8 +332,9 @@ bool st_set_trace_file_enabled(bool enable)
             return was_enabled;
         }
 
+        trace_event_iter_init_all(&iter);
         if (fwrite(&header, sizeof header, 1, trace_fp) != 1 ||
-            st_write_event_mapping() < 0) {
+            st_write_event_mapping(&iter) < 0) {
             fclose(trace_fp);
             trace_fp = NULL;
             return was_enabled;
@@ -422,3 +422,15 @@ bool st_init(void)
     atexit(st_flush_trace_buffer);
     return true;
 }
+
+void st_init_group(size_t group)
+{
+    TraceEventIter iter;
+
+    if (!trace_writeout_enabled) {
+        return;
+    }
+
+    trace_event_iter_init_group(&iter, group);
+    st_write_event_mapping(&iter);
+}

trace/simple.h

@@ -15,6 +15,7 @@ void st_print_trace_file_status(void);
 bool st_set_trace_file_enabled(bool enable);
 void st_set_trace_file(const char *file);
 bool st_init(void);
+void st_init_group(size_t group);
 void st_flush_trace_buffer(void);
 
 typedef struct {