trace: Add LTTng Userspace Tracer backend

This patch adds LTTng Userspace Tracer (UST) backend support.  The UST
system requires no kernel support but libust and liburcu must be
installed.

$ ./configure --trace-backend ust
$ make

Start the UST daemon:
$ ustd &

List available tracepoints and enable some:
$ ustctl --list-markers $(pgrep qemu)
[...]
{PID: 5458, channel/marker: ust/paio_submit, state: 0, fmt: "acb %p
opaque %p sector_num %lu nb_sectors %lu type %lu" 0x4b32ba}
$ ustctl --enable-marker "ust/paio_submit" $(pgrep qemu)

Run the trace:
$ ustctl --create-trace $(pgrep qemu)
$ ustctl --start-trace $(pgrep qemu)
[...]
$ ustctl --stop-trace $(pgrep qemu)
$ ustctl --destroy-trace $(pgrep qemu)

Trace results can be viewed using lttv-gui.

More information about UST:
http://lttng.org/ust

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

trace: Check for LTTng Userspace Tracer headers

When using the 'ust' backend, check if the relevant headers are
available at host.

Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/configure b/configure
index 234e75bf59..4061cb7045 100755
--- a/configure
+++ b/configure
@@ -903,7 +903,7 @@ echo "  --enable-docs            enable documentation build"
 echo "  --disable-docs           disable documentation build"
 echo "  --disable-vhost-net      disable vhost-net acceleration support"
 echo "  --enable-vhost-net       enable vhost-net acceleration support"
-echo "  --trace-backend=B        Trace backend nop simple"
+echo "  --trace-backend=B        Trace backend nop simple ust"
 echo "  --trace-file=NAME        Full PATH,NAME of file to store traces"
 echo "                           Default:trace-<pid>"
 echo ""
@@ -2080,6 +2080,24 @@ if test "$?" -ne 0 ; then
   exit 1
 fi
 
+##########################################
+# For 'ust' backend, test if ust headers are present
+if test "$trace_backend" = "ust"; then
+  cat > $TMPC << EOF
+#include <ust/tracepoint.h>
+#include <ust/marker.h>
+int main(void) { return 0; }
+EOF
+  if compile_prog "" "" ; then
+    LIBS="-lust $LIBS"
+  else
+    echo
+    echo "Error: Trace backend 'ust' missing libust header files"
+    echo
+    exit 1
+  fi
+fi
+##########################################
 # End of CC checks
 # After here, no more $cc or $ld runs