Add generic hp-timing support

Add missing generic hp_timing support.  It uses clock_gettime (CLOCK_MONOTONIC)
which has unspecified starting time, nano-second accuracy, and should faster on
architectures that implementes the symbol as vDSO.

Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu. I also
checked the builds for all afected ABIs.

	* benchtests/Makefile (USE_CLOCK_GETTIME) Remove.
	* benchtests/README: Update description.
	* benchtests/bench-timing.h: Default to hp-timing.
	* sysdeps/generic/hp-timing.h (HP_TIMING_DIFF, HP_TIMING_ACCUM_NT,
	HP_TIMING_PRINT): Remove.
	(HP_TIMING_NOW): Add generic implementation.
	(hp_timing_t): Change to uint64_t.

3 files changed, 9 insertions, 48 deletions

diff --git a/benchtests/Makefile b/benchtests/Makefile
index d00993eca4..cdc89488d6 100644
--- a/benchtests/Makefile
+++ b/benchtests/Makefile
@@ -127,17 +127,11 @@ endif
 
 CPPFLAGS-nonlib += -DDURATION=$(BENCH_DURATION) -D_ISOMAC
 
-# Use clock_gettime to measure performance of functions.  The default is to use
-# HP_TIMING if it is available.
-ifdef USE_CLOCK_GETTIME
-CPPFLAGS-nonlib += -DUSE_CLOCK_GETTIME
-else
 # On x86 processors, use RDTSCP, instead of RDTSC, to measure performance
 # of functions.  All x86 processors since 2010 support RDTSCP instruction.
 ifdef USE_RDTSCP
 CPPFLAGS-nonlib += -DUSE_RDTSCP
 endif
-endif
 
 DETAILED_OPT :=
 
diff --git a/benchtests/README b/benchtests/README
index aaf0b659e2..c4f03fd872 100644
--- a/benchtests/README
+++ b/benchtests/README
@@ -27,12 +27,7 @@ BENCH_DURATION.
 
 The benchmark suite does function call measurements using architecture-specific
 high precision timing instructions whenever available.  When such support is
-not available, it uses clock_gettime (CLOCK_PROCESS_CPUTIME_ID).  One can force
-the benchmark to use clock_gettime by invoking make as follows:
-
-  $ make USE_CLOCK_GETTIME=1 bench
-
-Again, one must run `make bench-clean' before changing the measurement method.
+not available, it uses clock_gettime (CLOCK_MONOTONIC).
 
 On x86 processors, RDTSCP instruction provides more precise timing data
 than RDTSC instruction.  All x86 processors since 2010 support RDTSCP
diff --git a/benchtests/bench-timing.h b/benchtests/bench-timing.h
index 93fe379f99..e213dec3fd 100644
--- a/benchtests/bench-timing.h
+++ b/benchtests/bench-timing.h
@@ -18,49 +18,21 @@
 
 #undef attribute_hidden
 #define attribute_hidden
+#define __clock_gettime clock_gettime
 #include <hp-timing.h>
 #include <stdint.h>
 
-#if HP_TIMING_INLINE && !defined USE_CLOCK_GETTIME
-# define GL(x) _##x
-# define GLRO(x) _##x
+#define GL(x) _##x
+#define GLRO(x) _##x
 typedef hp_timing_t timing_t;
 
-# define TIMING_TYPE "hp_timing"
+#define TIMING_TYPE "hp_timing"
 
-# define TIMING_INIT(res) ({ (res) = 1; })
+#define TIMING_INIT(res) ({ (res) = 1; })
 
-# define TIMING_NOW(var) HP_TIMING_NOW (var)
-# define TIMING_DIFF(diff, start, end) HP_TIMING_DIFF ((diff), (start), (end))
-# define TIMING_ACCUM(sum, diff) HP_TIMING_ACCUM_NT ((sum), (diff))
-
-#else
-
-#include <time.h>
-typedef uint64_t timing_t;
-
-# define TIMING_TYPE "clock_gettime"
-
-/* Measure the resolution of the clock so we can scale the number of
-   benchmark iterations by this value.  */
-# define TIMING_INIT(res) \
-({									      \
-  struct timespec start;						      \
-  clock_getres (CLOCK_PROCESS_CPUTIME_ID, &start);			      \
-  (res) = start.tv_nsec;					      \
-})
-
-# define TIMING_NOW(var) \
-({									      \
-  struct timespec tv;							      \
-  clock_gettime (CLOCK_PROCESS_CPUTIME_ID, &tv);			      \
-  (var) = (uint64_t) (tv.tv_nsec + (uint64_t) 1000000000 * tv.tv_sec);	      \
-})
-
-# define TIMING_DIFF(diff, start, end) (diff) = (end) - (start)
-# define TIMING_ACCUM(sum, diff) (sum) += (diff)
-
-#endif
+#define TIMING_NOW(var) HP_TIMING_NOW (var)
+#define TIMING_DIFF(diff, start, end) HP_TIMING_DIFF ((diff), (start), (end))
+#define TIMING_ACCUM(sum, diff) HP_TIMING_ACCUM_NT ((sum), (diff))
 
 #define TIMING_PRINT_MEAN(d_total_s, d_iters) \
   printf ("\t%g", (d_total_s) / (d_iters))