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Hi! 17214: runtime linker statistics: 17214: total startup time in dynamic loader: 12434 clock cycles 17214: time needed for relocation: 280243 clock cycles (%) 17214: number of relocations: 98 17214: number of relocations from cache: 3 17214: number of relative relocations: 1286 17214: time needed to load objects: 0 clock cycles (.0%) certainly doesn't look correct. The problem is that without volatile in the rdtsc asm GCC happily merges HP_TIMING_NOW (start); call something HP_TIMING_NOW (stop); so that stop == start (rdtsc done only before the call). 17232: runtime linker statistics: 17232: total startup time in dynamic loader: 733738 clock cycles 17232: time needed for relocation: 278644 clock cycles (37.9%) 17232: number of relocations: 83 17232: number of relocations from cache: 3 17232: number of relative relocations: 1295 17232: time needed to load objects: 326662 clock cycles (44.5%) looks better. 2004-03-17 Jakub Jelinek <jakub@redhat.com> * sysdeps/x86_64/hp-timing.h (HP_TIMING_NOW): Make asm volatile. --- libc/sysdeps/x86_64/hp-timing.h.jj 2002-08-31 01:09:29.000000000 +0200 +++ libc/sysdeps/x86_64/hp-timing.h 2004-03-17 13:26:02.139127766 +0100 @@ -1,5 +1,5 @@ /* High precision, low overhead timing functions. x86-64 version. - Copyright (C) 2002 Free Software Foundation, Inc. + Copyright (C) 2002, 2004 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -25,7 +25,8 @@ /* The "=A" constraint used in 32-bit mode does not work in 64-bit mode. */ # undef HP_TIMING_NOW # define HP_TIMING_NOW(Var) \ - ({ unsigned int _hi, _lo; asm ("rdtsc" : "=a" (_lo), "=d" (_hi)); \ + ({ unsigned int _hi, _lo; \ + asm volatile ("rdtsc" : "=a" (_lo), "=d" (_hi)); \ (Var) = ((unsigned long long int) _hi << 32) | _lo; }) /* The funny business for 32-bit mode is not required here. */ Jakub
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