nptl: Remove pthread_clock_gettime pthread_clock_settime

This patch removes CLOCK_THREAD_CPUTIME_ID and CLOCK_PROCESS_CPUTIME_ID support
from clock_gettime and clock_settime generic implementation.  For Linux, kernel
already provides supports through the syscall and Hurd HTL lacks
__pthread_clock_gettime and __pthread_clock_settime internal implementation.

As described in clock_gettime man-page [1] on 'Historical note for SMP
system', implementing CLOCK_{THREAD,PROCESS}_CPUTIME_ID with timer registers
is error-prone and susceptible to timing and accurary issues that the libc
can not deal without kernel support.

This allows removes unused code which, however, still incur in some runtime
overhead in thread creation (the struct pthread cpuclock_offset
initialization).

If hurd eventually wants to support them it should either either implement as
a kernel facility (or something related due its architecture) or in system
specific implementation.

Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu. I also
checked on a i686-gnu build.

	* nptl/Makefile (libpthread-routines): Remove pthread_clock_gettime and
	pthread_clock_settime.
	* nptl/pthreadP.h (__find_thread_by_id): Remove prototype.
	* elf/dl-support.c [!HP_TIMING_NOAVAIL] (_dl_cpuclock_offset): Remove.
	(_dl_non_dynamic_init): Remove _dl_cpuclock_offset setting.
	* elf/rtld.c (_dl_start_final): Likewise.
	* nptl/allocatestack.c (__find_thread_by_id): Remove function.
	* sysdeps/generic/ldsodefs.h [!HP_TIMING_NOAVAIL] (_dl_cpuclock_offset):
	Remove.
	* sysdeps/mach/hurd/dl-sysdep.c [!HP_TIMING_NOAVAIL]
	(_dl_cpuclock_offset): Remove.
	* nptl/descr.h (struct pthread): Rename cpuclock_offset to
	cpuclock_offset_ununsed.
	* nptl/nptl-init.c (__pthread_initialize_minimal_internal): Remove
	cpuclock_offset set.
	* nptl/pthread_create.c (START_THREAD_DEFN): Likewise.
	* sysdeps/nptl/fork.c (__libc_fork): Likewise.
	* nptl/pthread_clock_gettime.c: Remove file.
	* nptl/pthread_clock_settime.c: Likewise.
	* sysdeps/unix/clock_gettime.c (hp_timing_gettime): Remove function.
	[HP_TIMING_AVAIL] (realtime_gettime): Remove CLOCK_THREAD_CPUTIME_ID
	and CLOCK_PROCESS_CPUTIME_ID support.
	* sysdeps/unix/clock_settime.c (hp_timing_gettime): Likewise.
	[HP_TIMING_AVAIL] (realtime_gettime): Likewise.
	* sysdeps/posix/clock_getres.c (hp_timing_getres): Likewise.
	[HP_TIMING_AVAIL] (__clock_getres): Likewise.
	* sysdeps/unix/clock_nanosleep.c (CPUCLOCK_P, INVALID_CLOCK_P):
	Likewise.
	(__clock_nanosleep): Remove CPUCLOCK_P and INVALID_CLOCK_P usage.

[1] http://man7.org/linux/man-pages/man2/clock_gettime.2.html

2 files changed, 0 insertions, 10 deletions

diff --git a/elf/dl-support.c b/elf/dl-support.c
index 42c350c75d..0a8b636d02 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -129,11 +129,6 @@ void *_dl_random;
 #include <dl-procruntime.c>
 #include <dl-procinfo.c>
 
-/* Initial value of the CPU clock.  */
-#ifndef HP_TIMING_NONAVAIL
-hp_timing_t _dl_cpuclock_offset;
-#endif
-
 void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls;
 
 size_t _dl_pagesize = EXEC_PAGESIZE;
@@ -314,9 +309,6 @@ _dl_non_dynamic_init (void)
   _dl_main_map.l_phdr = GL(dl_phdr);
   _dl_main_map.l_phnum = GL(dl_phnum);
 
-  if (HP_SMALL_TIMING_AVAIL)
-    HP_TIMING_NOW (_dl_cpuclock_offset);
-
   _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
 
   /* Set up the data structures for the system-supplied DSO early,
diff --git a/elf/rtld.c b/elf/rtld.c
index 1b38c6b732..1f20d4a8c8 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -403,8 +403,6 @@ _dl_start_final (void *arg, struct dl_start_final_info *info)
 # endif
 #endif
 
-  HP_TIMING_NOW (GL(dl_cpuclock_offset));
-
   /* Initialize the stack end variable.  */
   __libc_stack_end = __builtin_frame_address (0);