This is the mail archive of the libc-hacker@sources.redhat.com mailing list for the glibc project.
Note that libc-hacker is a closed list. You may look at the archives of this list, but subscription and posting are not open.
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |
On Fri, Aug 31, 2001 at 06:41:28PM +0200, Jakub Jelinek wrote: > * sysdeps/alpha/dl-machine.h (elf_machine_rela): Remove unused code. > Don't add old memory content for R_ALPHA_REFQUAD. This is ok. I tested this plus variants that (1) Used __builtin_expect to avoid memcpy for the unaligned cases, and (2) Added a prefetch-with-write-intent against the relocation address at the top of the function. The result appears to be that these changes are in the noise. I used the following hack to get cycle counts from ld.so. It'd be nice if they could go in, but I could easily imagine Uli barfing. r~ Relocation performance summary: ls cvs emacs aspell relocs: 936 2431 4319 5431 cycles: OLD-ALIGN -17429 -120315 -260707 -90156 33515 180431 211068 -521220 -15865 58516 41576 -249110 OLD-PREFETCH -42554 1691 -118651 -250081 79639 142492 47157 98095 -41410 -62520 93174 -160 ALIGN-PREFETCH -25125 122006 142056 -159925 46124 -37939 -163911 619315 -25545 -121036 51598 248950 percent time: OLD-ALIGN 0.3 0.0 0.0 -0.3 -1.6 0.3 0.1 0.0 1.1 0.0 0.1 -0.1 OLD-PREFETCH -0.1 0.3 -0.1 0.0 -2.4 -0.2 -0.2 -0.1 1.2 0.0 0.0 0.0 * elf/dl-support.c (_dl_cpuclock_offset): Protect with NONAVAIL. (HP_TIMING_AVAIL): Set to HP_SMALL_TIMING_AVAIL if present. * elf/rtld.c (HP_TIMING_AVAIL): Likewise. (print_statistics): Make scalar unsigned long long. * sysdeps/alpha/hp-timing.h: New file. Index: elf/dl-support.c =================================================================== RCS file: /cvs/glibc/libc/elf/dl-support.c,v retrieving revision 1.52 diff -u -r1.52 dl-support.c --- dl-support.c 2001/07/27 03:48:11 1.52 +++ dl-support.c 2001/09/01 01:12:32 @@ -93,8 +93,14 @@ /* Nonzero during startup. */ int _dl_starting_up = 1; +/* We expect less than a second for relocation. */ +#ifdef HP_SMALL_TIMING_AVAIL +#undef HP_TIMING_AVAIL +#define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL +#endif + /* Initial value of the CPU clock. */ -#if HP_TIMING_AVAIL +#ifndef HP_TIMING_NONAVAIL hp_timing_t _dl_cpuclock_offset; #endif @@ -133,9 +139,8 @@ static void non_dynamic_init (void) { -#if HP_TIMING_AVAIL - HP_TIMING_NOW (_dl_cpuclock_offset); -#endif + if (HP_TIMING_AVAIL) + HP_TIMING_NOW (_dl_cpuclock_offset); if (!_dl_pagesize) _dl_pagesize = __getpagesize (); Index: elf/rtld.c =================================================================== RCS file: /cvs/glibc/libc/elf/rtld.c,v retrieving revision 1.207 diff -u -r1.207 rtld.c --- rtld.c 2001/08/27 16:21:32 1.207 +++ rtld.c 2001/09/01 01:12:33 @@ -121,6 +121,12 @@ struct libname_list _dl_rtld_libname; struct libname_list _dl_rtld_libname2; +/* We expect less than a second for relocation. */ +#ifdef HP_SMALL_TIMING_AVAIL +#undef HP_TIMING_AVAIL +#define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL +#endif + /* Variable for statistics. */ #ifndef HP_TIMING_NONAVAIL static hp_timing_t rtld_total_time; @@ -1506,7 +1512,7 @@ { char pbuf[30]; HP_TIMING_PRINT (buf, sizeof (buf), relocate_time); - cp = _itoa_word ((1000 * relocate_time) / rtld_total_time, + cp = _itoa_word ((1000ULL * relocate_time) / rtld_total_time, pbuf + sizeof (pbuf), 10, 0); wp = pbuf; switch (pbuf + sizeof (pbuf) - cp) @@ -1535,7 +1541,7 @@ { char pbuf[30]; HP_TIMING_PRINT (buf, sizeof (buf), load_time); - cp = _itoa_word ((1000 * load_time) / rtld_total_time, + cp = _itoa_word ((1000ULL * load_time) / rtld_total_time, pbuf + sizeof (pbuf), 10, 0); wp = pbuf; switch (pbuf + sizeof (pbuf) - cp) --- /dev/null Thu Oct 19 13:35:05 2000 +++ sysdeps/alpha/hp-timing.h Fri Aug 31 18:18:02 2001 @@ -0,0 +1,118 @@ +/* High precision, low overhead timing functions. IA-64 version. + Copyright (C) 2001 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Richard Henderson <rth@redhat.com>, 2001. + + 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> + +/* The macros defined here use the timestamp counter in IA-64. They + provide a very accurate way to measure the time with very little + overhead. The time values themself have no real meaning, only + differences are interesting. + + 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 have the timestamp register, but it's got only a 4 second + range. Use it for ld.so profiling only. */ +#define HP_TIMING_AVAIL (0) +#define HP_SMALL_TIMING_AVAIL (1) + +/* We indeed have inlined functions. */ +#define HP_TIMING_INLINE (1) + +/* We use 32 bit values for the times. */ +typedef unsigned int hp_timing_t; + +/* Set timestamp value to zero. */ +#define HP_TIMING_ZERO(VAR) (VAR) = (0) + +/* The "rpcc" instruction returns a 32-bit counting half and a 32-bit + "virtual cycle counter displacement". Subtracting the two gives us + a virtual cycle count. */ +#define HP_TIMING_NOW(VAR) \ + do { \ + unsigned long x_; \ + asm volatile ("rpcc %0" : "=r"(x_)); \ + (VAR) = (int)(x_) - (int)(x_ >> 32); \ + } while (0) + +/* ??? Two rpcc instructions can be scheduled simultaneously. */ +#define HP_TIMING_DIFF_INIT() do { } while (0) + +/* It's simple arithmetic for us. */ +#define HP_TIMING_DIFF(Diff, Start, End) (Diff) = ((End) - (Start)) + +/* ??? Don't bother, since we're only used for ld.so. */ +#define HP_TIMING_ACCUM(Sum, Diff) not implemented + +/* 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_word (Val, __buf + sizeof (__buf), 10, 0); \ + int __len = (Len); \ + char *__dest = (Buf); \ + while (__len-- > 0 && __cp < __buf + sizeof (__buf)) \ + *__dest++ = *__cp++; \ + memcpy (__dest, " clock cycles", MIN (__len, sizeof (" clock cycles"))); \ + } while (0) + +#endif /* hp-timing.h */
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |