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[PATCH] hp-timing for ppc32/64
- From: Steve Munroe <sjmunroe at us dot ibm dot com>
- To: libc-alpha at sources dot redhat dot com
- Date: Mon, 10 Oct 2005 17:18:56 -0500
- Subject: [PATCH] hp-timing for ppc32/64
- Reply-to: sjmunroe at vnet dot ibm dot com
This patch adds hp-timing for powerpc32 and powerpc64.
2005-10-10 Steven Munroe <sjmunroe@us.ibm.com>
* sysdeps/powerpc/powerpc32/Makefile
(sysdep_routines, elide-routines.os): Add hp-timing.
* sysdeps/powerpc/powerpc32/hp-timing.c: New file.
* sysdeps/powerpc/powerpc32/hp-timing.h: New file.
* sysdeps/powerpc/powerpc64/Makefile
(sysdep_routines, elide-routines.os): Add hp-timing.
* sysdeps/powerpc/powerpc64/hp-timing.c: New file.
* sysdeps/powerpc/powerpc64/hp-timing.h: New file.
diff -urN libc24-cvstip-20050926/sysdeps/powerpc/powerpc32/Makefile libc24/sysdeps/powerpc/powerpc32/Makefile
--- libc24-cvstip-20050926/sysdeps/powerpc/powerpc32/Makefile 2005-08-04 16:35:43.000000000 -0500
+++ libc24/sysdeps/powerpc/powerpc32/Makefile 2005-10-10 10:19:48.000000000 -0500
@@ -18,6 +18,8 @@
endif
ifeq ($(subdir),csu)
+sysdep_routines += hp-timing
+elide-routines.os += hp-timing
ifneq ($(elf),no)
# The initfini generation code doesn't work in the presence of -fPIC, so
# we use -fpic instead which is much better.
diff -urN libc24-cvstip-20050926/sysdeps/powerpc/powerpc32/hp-timing.c libc24/sysdeps/powerpc/powerpc32/hp-timing.c
--- libc24-cvstip-20050926/sysdeps/powerpc/powerpc32/hp-timing.c Wed Dec 31 18:00:00 1969
+++ libc24/sysdeps/powerpc/powerpc32/hp-timing.c Mon Oct 10 16:02:23 2005
@@ -0,0 +1,27 @@
+/* Support for high precision, low overhead timing functions.
+ powerpc32 version.
+ Copyright (C) 2005 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <hp-timing.h>
+
+/* We have to define a variable for the overhead and thread locking.
+ To avoid false sharing and potential "live lock" we need to insure that
+ the hp_timing lock is in a cache line by itself. */
+hp_timing_t _dl_hp_timing_overhead __attribute__((aligned(128)));
diff -urN libc24-cvstip-20050926/sysdeps/powerpc/powerpc32/hp-timing.h libc24/sysdeps/powerpc/powerpc32/hp-timing.h
--- libc24-cvstip-20050926/sysdeps/powerpc/powerpc32/hp-timing.h Wed Dec 31 18:00:00 1969
+++ libc24/sysdeps/powerpc/powerpc32/hp-timing.h Mon Oct 10 15:30:27 2005
@@ -0,0 +1,183 @@
+/* High precision, low overhead timing functions. powerpc32 version.
+ Copyright (C) 2005 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _HP_TIMING_H
+#define _HP_TIMING_H 1
+
+#include <string.h>
+#include <sys/param.h>
+#include <stdio-common/_itoa.h>
+#include <atomic.h>
+
+/* The macros defined here use the powerpc 64-bit time base register.
+ The time base is nominally clocked at 1/8th the CPU clock, but this
+ can vary.
+
+ The list of macros we need includes the following:
+
+ - HP_TIMING_AVAIL: test for availability.
+
+ - HP_TIMING_INLINE: this macro is non-zero if the functionality is not
+ implemented using function calls but instead uses some inlined code
+ which might simply consist of a few assembler instructions. We have to
+ know this since we might want to use the macros here in places where we
+ cannot make function calls.
+
+ - hp_timing_t: This is the type for variables used to store the time
+ values.
+
+ - HP_TIMING_ZERO: clear `hp_timing_t' object.
+
+ - HP_TIMING_NOW: place timestamp for current time in variable given as
+ parameter.
+
+ - HP_TIMING_DIFF_INIT: do whatever is necessary to be able to use the
+ HP_TIMING_DIFF macro.
+
+ - HP_TIMING_DIFF: compute difference between two times and store it
+ in a third. Source and destination might overlap.
+
+ - HP_TIMING_ACCUM: add time difference to another variable. This might
+ be a bit more complicated to implement for some platforms as the
+ operation should be thread-safe and 64bit arithmetic on 32bit platforms
+ is not.
+
+ - HP_TIMING_ACCUM_NT: this is the variant for situations where we know
+ there are no threads involved.
+
+ - HP_TIMING_PRINT: write decimal representation of the timing value into
+ the given string. This operation need not be inline even though
+ HP_TIMING_INLINE is specified.
+
+*/
+
+/* We always assume having the timestamp register. */
+#define HP_TIMING_AVAIL (1)
+
+/* We indeed have inlined functions. */
+#define HP_TIMING_INLINE (1)
+
+/* We use 64bit values for the times. */
+typedef unsigned long long int hp_timing_t;
+
+typedef union hp_timing_ut
+ {
+ hp_timing_t ll_tb;
+ unsigned long l_tb[2];
+ } hp_timing_ut;
+
+
+/* Set timestamp value to zero. */
+#define HP_TIMING_ZERO(Var) (Var) = (0)
+
+/* Use the `mftbu'/`mftb' instructions to obtain the 64-bit timebase
+ 32-bits at a time. We need to insure that the upper timebase is
+ consistent with the lower timebase. So we read the upper timebase
+ before and after we read the lower timebase then compare them.
+ If the two upper timebase values are equal we are done. Otherwise the
+ lower timebase may have wrapper, so we repeat the sequence.
+
+ Note that the value might not be 100% accurate since there might be
+ some more instructions running in this moment. */
+#define HP_TIMING_NOW(Var) \
+ do { \
+ unsigned long __temp; \
+ hp_timing_ut tmp_val; \
+ __asm __volatile ( \
+ "1: mftbu %0\n" \
+ " mftb %1\n" \
+ " mftbu %2\n" \
+ " cmpw %0,%2\n" \
+ " bne- 1b\n" \
+ : "=r" (tmp_val.l_tb[0]), "=r" (tmp_val.l_tb[1]), \
+ "=r" (__temp) \
+ : \
+ : "cr0", "memory"); \
+ Var = tmp_val.ll_tb; \
+ } while (0)
+
+/* Use two 'mftb/mftbu' sequences in a row to find out how long it takes.
+ On current POWER4, POWER5, and 970 processors mftb/mftbu ibstructions
+ take ~10 cycles each. */
+#define HP_TIMING_DIFF_INIT() \
+ do { \
+ if (GLRO(dl_hp_timing_overhead) == 0) \
+ { \
+ int __cnt = 5; \
+ GLRO(dl_hp_timing_overhead) = ~0ull; \
+ do \
+ { \
+ hp_timing_t __t1, __t2; \
+ HP_TIMING_NOW (__t1); \
+ HP_TIMING_NOW (__t2); \
+ if (__t2 - __t1 < GLRO(dl_hp_timing_overhead)) \
+ GLRO(dl_hp_timing_overhead) = __t2 - __t1; \
+ } \
+ while (--__cnt > 0); \
+ } \
+ } while (0)
+
+/* It's simple arithmetic in 64-bit. */
+#define HP_TIMING_DIFF(Diff, Start, End) (Diff) = ((End) - (Start))
+
+/* We need to insure that this add is atomic in threaded environments.
+ But we want this needs to be a "light-weight" as posible. So we create a
+ simple lwarx lock on the 1st word of dl_hp_timing_overhead. The lwarx gets
+ the reservation and (attempts to hold it while we compute long long sum.
+ We follow this with a conditional stwcx to verify that no other thread
+ took the reservation while we computed the sum. We don't care
+ about the value of the lock word, and don't change the value. */
+#define HP_TIMING_ACCUM(Sum, Diff) \
+ do { \
+ hp_timing_t __diff = (Diff) - GLRO(dl_hp_timing_overhead); \
+ void *lock = & GLRO(dl_hp_timing_overhead); \
+ unsigned int __tmp; \
+ __asm __volatile ( \
+ "1: lwarx %0,0,%1\n" \
+ " " __ARCH_ACQ_INSTR "\n" \
+ : "=&r" (__tmp) \
+ : "b" (lock) \
+ ); \
+ (Sum) += (__diff); \
+ __asm __volatile ( \
+ " " __ARCH_REL_INSTR "\n" \
+ " stwcx. %0,0,%1\n" \
+ " bne- 1b\n" \
+ : \
+ : "r" (__tmp), "b" (lock) \
+ : "cr0", "memory"); \
+ } while (0)
+
+/* No threads, no extra work. */
+#define HP_TIMING_ACCUM_NT(Sum, Diff) (Sum) += (Diff)
+
+/* Print the time value. */
+#define HP_TIMING_PRINT(Buf, Len, Val) \
+ do { \
+ char __buf[20]; \
+ char *__cp = _itoa (Val, __buf + sizeof (__buf), 10, 0); \
+ size_t __len = (Len); \
+ char *__dest = (Buf); \
+ while (__len-- > 0 && __cp < __buf + sizeof (__buf)) \
+ *__dest++ = *__cp++; \
+ memcpy (__dest, " ticks", MIN (__len, sizeof (" ticks"))); \
+ } while (0)
+
+#endif /* hp-timing.h */
diff -urN libc24-cvstip-20050926/sysdeps/powerpc/powerpc64/Makefile libc24/sysdeps/powerpc/powerpc64/Makefile
--- libc24-cvstip-20050926/sysdeps/powerpc/powerpc64/Makefile 2005-08-04 16:35:44.000000000 -0500
+++ libc24/sysdeps/powerpc/powerpc64/Makefile 2005-10-07 16:32:01.000000000 -0500
@@ -11,6 +11,8 @@
endif
ifeq ($(subdir),csu)
+sysdep_routines += hp-timing
+elide-routines.os += hp-timing
ifneq ($(elf),no)
# The initfini generation code doesn't work in the presence of -fPIC, so
# we use -fpic instead which is much better.
diff -urN libc24-cvstip-20050926/sysdeps/powerpc/powerpc64/hp-timing.c libc24/sysdeps/powerpc/powerpc64/hp-timing.c
--- libc24-cvstip-20050926/sysdeps/powerpc/powerpc64/hp-timing.c Wed Dec 31 18:00:00 1969
+++ libc24/sysdeps/powerpc/powerpc64/hp-timing.c Fri Oct 07 17:00:58 2005
@@ -0,0 +1,25 @@
+/* Support for high precision, low overhead timing functions.
+ powerpc64 version.
+ Copyright (C) 2005 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <hp-timing.h>
+
+/* We have to define the variable for the overhead. */
+hp_timing_t _dl_hp_timing_overhead;
diff -urN libc24-cvstip-20050926/sysdeps/powerpc/powerpc64/hp-timing.h libc24/sysdeps/powerpc/powerpc64/hp-timing.h
--- libc24-cvstip-20050926/sysdeps/powerpc/powerpc64/hp-timing.h Wed Dec 31 18:00:00 1969
+++ libc24/sysdeps/powerpc/powerpc64/hp-timing.h Mon Oct 10 13:24:05 2005
@@ -0,0 +1,136 @@
+/* High precision, low overhead timing functions. powerpc64 version.
+ Copyright (C) 2005 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _HP_TIMING_H
+#define _HP_TIMING_H 1
+
+#include <string.h>
+#include <sys/param.h>
+#include <stdio-common/_itoa.h>
+#include <atomic.h>
+
+/* The macros defined here use the powerpc 64-bit time base register.
+ The time base is nominally clocked at 1/8th the CPU clock, but this
+ can vary.
+
+ The list of macros we need includes the following:
+
+ - HP_TIMING_AVAIL: test for availability.
+
+ - HP_TIMING_INLINE: this macro is non-zero if the functionality is not
+ implemented using function calls but instead uses some inlined code
+ which might simply consist of a few assembler instructions. We have to
+ know this since we might want to use the macros here in places where we
+ cannot make function calls.
+
+ - hp_timing_t: This is the type for variables used to store the time
+ values.
+
+ - HP_TIMING_ZERO: clear `hp_timing_t' object.
+
+ - HP_TIMING_NOW: place timestamp for current time in variable given as
+ parameter.
+
+ - HP_TIMING_DIFF_INIT: do whatever is necessary to be able to use the
+ HP_TIMING_DIFF macro.
+
+ - HP_TIMING_DIFF: compute difference between two times and store it
+ in a third. Source and destination might overlap.
+
+ - HP_TIMING_ACCUM: add time difference to another variable. This might
+ be a bit more complicated to implement for some platforms as the
+ operation should be thread-safe and 64bit arithmetic on 32bit platforms
+ is not.
+
+ - HP_TIMING_ACCUM_NT: this is the variant for situations where we know
+ there are no threads involved.
+
+ - HP_TIMING_PRINT: write decimal representation of the timing value into
+ the given string. This operation need not be inline even though
+ HP_TIMING_INLINE is specified.
+
+*/
+
+/* We always assume having the timestamp register. */
+#define HP_TIMING_AVAIL (1)
+
+/* We indeed have inlined functions. */
+#define HP_TIMING_INLINE (1)
+
+/* We use 64bit values for the times. */
+typedef unsigned long long int hp_timing_t;
+
+/* Set timestamp value to zero. */
+#define HP_TIMING_ZERO(Var) (Var) = (0)
+
+/* That's quite simple. Use the `mftb' instruction. Note that the value
+ might not be 100% accurate since there might be some more instructions
+ running in this moment. This could be changed by using a barrier like
+ 'lwsync' right before the `mftb' instruciton. But we are not interested
+ in accurate clock cycles here so we don't do this. */
+#define HP_TIMING_NOW(Var) __asm__ __volatile__ ("mftb %0" : "=r" (Var))
+
+/* Use two 'mftb' instructions in a row to find out how long it takes.
+ On current POWER4, POWER5, and 970 processors mftb take ~10 cycles. */
+#define HP_TIMING_DIFF_INIT() \
+ do { \
+ if (GLRO(dl_hp_timing_overhead) == 0) \
+ { \
+ int __cnt = 5; \
+ GLRO(dl_hp_timing_overhead) = ~0ull; \
+ do \
+ { \
+ hp_timing_t __t1, __t2; \
+ HP_TIMING_NOW (__t1); \
+ HP_TIMING_NOW (__t2); \
+ if (__t2 - __t1 < GLRO(dl_hp_timing_overhead)) \
+ GLRO(dl_hp_timing_overhead) = __t2 - __t1; \
+ } \
+ while (--__cnt > 0); \
+ } \
+ } while (0)
+
+/* It's simple arithmetic in 64-bit. */
+#define HP_TIMING_DIFF(Diff, Start, End) (Diff) = ((End) - (Start))
+
+/* We need to insure that this add is atomic in threaded environments. We use
+ __arch_atomic_exchange_and_add_64 from atomic.h to get thread safety. */
+#define HP_TIMING_ACCUM(Sum, Diff) \
+ do { \
+ hp_timing_t __diff = (Diff) - GLRO(dl_hp_timing_overhead); \
+ __arch_atomic_exchange_and_add_64 (&(Sum), __diff); \
+ } while (0)
+
+/* No threads, no extra work. */
+#define HP_TIMING_ACCUM_NT(Sum, Diff) (Sum) += (Diff)
+
+/* Print the time value. */
+#define HP_TIMING_PRINT(Buf, Len, Val) \
+ do { \
+ char __buf[20]; \
+ char *__cp = _itoa (Val, __buf + sizeof (__buf), 10, 0); \
+ size_t __len = (Len); \
+ char *__dest = (Buf); \
+ while (__len-- > 0 && __cp < __buf + sizeof (__buf)) \
+ *__dest++ = *__cp++; \
+ memcpy (__dest, " ticks", MIN (__len, sizeof (" ticks"))); \
+ } while (0)
+
+#endif /* hp-timing.h */