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authorHarald Welte <laforge@osmocom.org>2020-09-26 11:51:32 +0200
committerlaforge <laforge@osmocom.org>2021-02-03 13:55:40 +0000
commit433005c87c88912358bfd02d4b0d997b52b04013 (patch)
treed5f71f3faff20b53daf14a4975b33b3284babe1d
parentdc43f7d3c73dc4cbe4e94668c635f056756f6d8a (diff)
initial support for static userspace probes via systemtap
This adds a --enable-systemtap configure option, which will then add static tracepoints to the generated libosmocore binary. At this point, only two tracepoints are supported: log_start and log_done. They can be used to trace the amount of time a libosmocore-using application spends in potentiall blocking calls to log to stderr or to files. Related: OS#4311 Change-Id: I7e1ab664241deb524c9582cbd1bec31af46c747e
-rw-r--r--Makefile.am2
-rw-r--r--configure.ac33
-rw-r--r--src/Makefile.am12
-rw-r--r--src/logging.c13
-rw-r--r--src/probes.d4
-rw-r--r--tapset/Makefile.am22
-rw-r--r--tapset/libosmocore.stp18
7 files changed, 103 insertions, 1 deletions
diff --git a/Makefile.am b/Makefile.am
index f2a05a96..ab2aad92 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,7 +1,7 @@
ACLOCAL_AMFLAGS = -I m4
AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include
-SUBDIRS = include src src/vty src/codec src/gsm src/coding src/gb src/ctrl src/sim src/pseudotalloc src/usb utils tests
+SUBDIRS = include src src/vty src/codec src/gsm src/coding src/gb src/ctrl src/sim src/pseudotalloc src/usb utils tapset tests
pkgconfigdir = $(libdir)/pkgconfig
pkgconfig_DATA = libosmocore.pc libosmocodec.pc libosmovty.pc libosmogsm.pc \
diff --git a/configure.ac b/configure.ac
index 2077570f..2a6a1807 100644
--- a/configure.ac
+++ b/configure.ac
@@ -433,6 +433,38 @@ AC_MSG_CHECKING([whether to enable ARM NEON instructions support])
AC_MSG_RESULT([$neon])
AM_CONDITIONAL(HAVE_NEON, [test "x$neon" != "xno"])
+#
+# SystemTap support
+#
+AC_MSG_CHECKING([whether to include systemtap tracing support])
+AC_ARG_ENABLE([systemtap],
+ [AS_HELP_STRING([--enable-systemtap],
+ [Enable inclusion of systemtap trace support])],
+ [ENABLE_SYSTEMTAP="${enableval}"], [ENABLE_SYSTEMTAP='no'])
+AM_CONDITIONAL([ENABLE_SYSTEMTAP], [test x$ENABLE_SYSTEMTAP = xyes])
+AC_MSG_RESULT(${ENABLE_SYSTEMTAP})
+
+if test "x${ENABLE_SYSTEMTAP}" = xyes; then
+ # Additional configuration for --enable-systemtap is HERE
+ AC_CHECK_PROGS(DTRACE, dtrace)
+ if test -z "$DTRACE"; then
+ AC_MSG_ERROR([dtrace not found])
+ fi
+ AC_CHECK_HEADER([sys/sdt.h], [SDT_H_FOUND='yes'],
+ [SDT_H_FOUND='no';
+ AC_MSG_ERROR([systemtap support needs sys/sdt.h header])])
+ AC_DEFINE([HAVE_SYSTEMTAP], [1], [Define to 1 if using SystemTap probes.])
+ AC_ARG_WITH([tapset-install-dir],
+ [AS_HELP_STRING([--with-tapset-install-dir],
+ [The absolute path where the tapset dir will be installed])],
+ [if test "x${withval}" = x; then
+ ABS_TAPSET_DIR="\$(datadir)/systemtap/tapset"
+ else
+ ABS_TAPSET_DIR="${withval}"
+ fi], [ABS_TAPSET_DIR="\$(datadir)/systemtap/tapset"])
+ AC_SUBST(ABS_TAPSET_DIR)
+fi
+
OSMO_AC_CODE_COVERAGE
@@ -487,6 +519,7 @@ AC_OUTPUT(
src/gb/Makefile
src/ctrl/Makefile
src/pseudotalloc/Makefile
+ tapset/Makefile
tests/Makefile
tests/atlocal
utils/Makefile
diff --git a/src/Makefile.am b/src/Makefile.am
index dd31db88..a2566a33 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -29,6 +29,7 @@ libosmocore_la_SOURCES = context.c timer.c timer_gettimeofday.c timer_clockgetti
use_count.c \
exec.c \
it_q.c \
+ probes.d \
$(NULL)
if HAVE_SSSE3
@@ -82,5 +83,16 @@ libosmocore_la_SOURCES += mnl.c
libosmocore_la_LIBADD += $(LIBMNL_LIBS)
endif
+if ENABLE_SYSTEMTAP
+probes.h: probes.d
+ $(DTRACE) -C -h -s $< -o $@
+
+probes.lo: probes.d
+ $(LIBTOOL) --mode=compile $(AM_V_lt) --tag=CC env CFLAGS="$(CFLAGS)" $(DTRACE) -C -G -s $< -o $@
+
+BUILT_SOURCES += probes.h probes.lo
+libosmocore_la_LIBADD += probes.lo
+endif
+
crc%gen.c: crcXXgen.c.tpl
$(AM_V_GEN)sed -e's/XX/$*/g' $< > $@
diff --git a/src/logging.c b/src/logging.c
index 60dba64c..a40008e9 100644
--- a/src/logging.c
+++ b/src/logging.c
@@ -44,6 +44,17 @@
#include <syslog.h>
#endif
+#ifdef HAVE_SYSTEMTAP
+/* include the generated probes header and put markers in code */
+#include "probes.h"
+#define TRACE(probe) probe
+#define TRACE_ENABLED(probe) probe ## _ENABLED()
+#else
+/* Wrap the probe to allow it to be removed when no systemtap available */
+#define TRACE(probe)
+#define TRACE_ENABLED(probe) (0)
+#endif /* HAVE_SYSTEMTAP */
+
#include <time.h>
#include <sys/time.h>
#include <errno.h>
@@ -670,9 +681,11 @@ void logp2(int subsys, unsigned int level, const char *file, int line, int cont,
{
va_list ap;
+ TRACE(LIBOSMOCORE_LOG_START());
va_start(ap, format);
osmo_vlogp(subsys, level, file, line, cont, format, ap);
va_end(ap);
+ TRACE(LIBOSMOCORE_LOG_DONE());
}
/*! Register a new log target with the logging core
diff --git a/src/probes.d b/src/probes.d
new file mode 100644
index 00000000..c16eb1ee
--- /dev/null
+++ b/src/probes.d
@@ -0,0 +1,4 @@
+provider libosmocore {
+ probe log_start();
+ probe log_done();
+};
diff --git a/tapset/Makefile.am b/tapset/Makefile.am
new file mode 100644
index 00000000..a07a3b1d
--- /dev/null
+++ b/tapset/Makefile.am
@@ -0,0 +1,22 @@
+.PHONY: clean-local install-data-hook uninstall-local
+
+EXTRA_DIST = libosmocore.stp
+TAPSET_FILES = $(EXTRA_DIST)
+TAPSET_INSTALL_DIR = $(DESTDIR)@ABS_TAPSET_DIR@
+
+if ENABLE_SYSTEMTAP
+all-local: $(TAPSET_FILES)
+
+clean-local:
+
+install-data-hook:
+ $(MKDIR_P) $(TAPSET_INSTALL_DIR)
+ $(INSTALL_DATA) $(TAPSET_FILES) $(TAPSET_INSTALL_DIR)
+
+uninstall-local:
+ @list='$(TAPSET_FILES)'; for p in $$list; do \
+ echo " rm -f '$(TAPSET_INSTALL_DIR)/$$p'"; \
+ rm -f "$(TAPSET_INSTALL_DIR)/$$p"; \
+ done
+
+endif
diff --git a/tapset/libosmocore.stp b/tapset/libosmocore.stp
new file mode 100644
index 00000000..0ec3c423
--- /dev/null
+++ b/tapset/libosmocore.stp
@@ -0,0 +1,18 @@
+/* libosmocore tapset
+ *
+ * This file is part of libosmocore.
+ *
+ * Each probe defines the probe name and a full probestr which consist of the probe name and between
+ * brackets all argument names and values.
+ */
+
+probe libosmocore_log_start = process("libosmocore").mark("log_start")
+{
+ count = $arg1;
+ probestr = sprintf("%s(count=%d), $$name, count);
+}
+
+probe libosmocore_log_done = process("libosmocore").mark("log_done")
+{
+ probestr = sprintf("%s", $$name);
+}