Message-ID: <3A37FFFE.E8283CF7@computer.org>
Date: Wed, 13 Dec 2000 23:02:22 +0000
From: Garry Smith
double When(void) { #if defined(CLOCKCYCLE) #define CLOCKSPEED 450 /* you can get this from /proc/cpuinfo */ internal_clk_t cycletime; read_cycle_counter(&cycletime); return ( ( cycletime / (double) CLOCKSPEED ) * 1e-6 ); #else struct timeval tp; gettimeofday(&tp, NULL); return ((double) tp.tv_sec + (double) tp.tv_usec * 1e-6); #endif }
The HW clock codes: --%<-------------%<--------------------- /* * Copyright (c) 1997 The President and Fellows of Harvard College. * All rights reserved. * Copyright (c) 1997 Aaron B. Brown. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program, in the file COPYING in this distribution; * if not, write to the Free Software Foundation, Inc., 675 Mass Ave, * Cambridge, MA 02139, USA. * * Results obtained from this benchmark may be published only under the * name "HBench-OS". */
/* * cyclecounter.c -- interface to hardware cycle counters for the i386 * * $Id: cyclecounter.c,v 1.3 1997/06/27 00:35:25 abrown Exp $ */
/* * These are very architecture specific. For each architecture, the following * must be present * * * a typedef for clk_t, the data type used to represent clock values * externally--should be something that the compiler can use without * choking (i.e. gcc 2.4.5 won't use register variables anywhere in * a function when you pass 64-bit types around on the x86) * * a typedef for internal_clk_t, the data type which represents clock * values internally. This should support the full resolution of the * timer (e.g. 64 bits on the x86) * * a required function * void read_counter(internal_clk_t *rtnval) * * a non-required function * void zero_counter(void) */
#if defined(i386) && defined(__GNUC__)
/* must define u_int64_t */ #if defined(__bsdi__) #include
#else #include #endif /* * This requires, but cannot check for from user level, a Pentium or newer * processor supporting the RDTSC instruction. * The assembly also requires gcc. * We also need %qd support in printf for printing quads, and a strtoq * instruction for the TCP bandwidth test. */
typedef u_int32_t clk_t; /* time stamps are 64 bit on the Pentium Pro */ typedef u_int64_t internal_clk_t; #define CLKTFMT "%d" #define CLKTSTR(x) ((int)strtol(x, NULL, 10))
/* * Read function: read hardware timestamp (cycle) counter */ #define read_cycle_counter(res_p) \ __asm __volatile ( \ ".byte 0xf; .byte 0x31 # RDTSC instruction \n\ movl %%edx, %1 # High order 32 bits \n\ movl %%eax, %0 # Low order 32 bits" \ : "=g" (*(int *)(res_p)), "=g" (*(((int *)res_p)+1)) \ : /* no input regs */ \ : "eax", "edx")
/* * Zero function: can't implement from user level */ void zero_cycle_counter() { return; }
#else /* i386 */ #error Cycle counter support requires a Pentium or Pentium Pro, and gcc #endif