>From f103ce07fcc4b1e6c69105f77ac323a380062571 Mon Sep 17 00:00:00 2001 From: Torsten Polle Date: Sun, 30 Jul 2017 08:54:36 +0200 Subject: [PATCH 1/2] Support inlined local_clock(). The following commit inlines local_clock(), which breaks the detection whether local_clock() is supported by the kernel. commit 2c923e94cd9c6acff3b22f0ae29cfe65e2658b40 Author: Daniel Lezcano Date: Mon Apr 11 16:38:34 2016 +0200 --- buildrun.cxx | 2 +- runtime/linux/autoconf-local-clock.c | 31 +++++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+), 1 deletion(-) create mode 100644 runtime/linux/autoconf-local-clock.c diff --git a/buildrun.cxx b/buildrun.cxx index 8bf122d..b2018dc 100644 --- a/buildrun.cxx +++ b/buildrun.cxx @@ -406,7 +406,7 @@ compile_pass (systemtap_session& s) // used by tapset/timestamp_monotonic.stp output_exportconf(s, o, "cpu_clock", "STAPCONF_CPU_CLOCK"); - output_exportconf(s, o, "local_clock", "STAPCONF_LOCAL_CLOCK"); + output_autoconf(s, o, "autoconf-local-clock.c", "STAPCONF_LOCAL_CLOCK", NULL); // used by runtime/uprobe-inode.c output_either_exportconf(s, o, "uprobe_register", "register_uprobe", diff --git a/runtime/linux/autoconf-local-clock.c b/runtime/linux/autoconf-local-clock.c new file mode 100644 index 0000000..d0439fd --- /dev/null +++ b/runtime/linux/autoconf-local-clock.c @@ -0,0 +1,31 @@ +#include + +// +// The following kernel commit inlined the local_clock() +// +// commit 2c923e94cd9c6acff3b22f0ae29cfe65e2658b40 +// Author: Daniel Lezcano +// Date: Mon Apr 11 16:38:34 2016 +0200 +// +// sched/clock: Make local_clock()/cpu_clock() inline +// +// The local_clock/cpu_clock functions were changed to prevent a double +// identical test with sched_clock_cpu() when HAVE_UNSTABLE_SCHED_CLOCK +// is set. That resulted in one line functions. +// +// As these functions are in all the cases one line functions and in the +// hot path, it is useful to specify them as static inline in order to +// give a strong hint to the compiler. +// +// After verification, it appears the compiler does not inline them +// without this hint. Change those functions to static inline. +// +// sched_clock_cpu() is called via the inlined local_clock()/cpu_clock() +// functions from sched.h. So any module code including sched.h will +// reference sched_clock_cpu(). Thus it must be exported with the +// EXPORT_SYMBOL_GPL macro. +// + +void foo (void) { + (void) local_clock(); +} -- 2.7.4