1 /* 2 * Copyright (c) 2014 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 /* 36 * UKP-Optimized clock_gettime(). Use the kpmap after the 10th call. 37 */ 38 39 #include <sys/cdefs.h> 40 #include <sys/types.h> 41 #include <sys/syscall.h> 42 #include <sys/upmap.h> 43 #include <sys/time.h> 44 #include <machine/cpufunc.h> 45 #include <errno.h> 46 #include <time.h> 47 #include <stdio.h> 48 #include <unistd.h> 49 /*#include "un-namespace.h"*/ 50 #include "libc_private.h" 51 #include "upmap.h" 52 53 extern int __sys_clock_gettime(clockid_t clock_id, struct timespec *ts); 54 int __clock_gettime(clockid_t clock_id, struct timespec *ts); 55 56 static int fast_clock; 57 static int fast_count; 58 static int *upticksp; 59 static struct timespec *ts_uptime; 60 static struct timespec *ts_realtime; 61 62 int 63 __clock_gettime(clockid_t clock_id, struct timespec *ts) 64 { 65 int res; 66 int w; 67 68 if (fast_clock == 0 && fast_count++ >= 10) { 69 __kpmap_map(&upticksp, &fast_clock, KPTYPE_UPTICKS); 70 __kpmap_map(&ts_uptime, &fast_clock, KPTYPE_TS_UPTIME); 71 __kpmap_map(&ts_realtime, &fast_clock, KPTYPE_TS_REALTIME); 72 __kpmap_map(NULL, &fast_clock, 0); 73 } 74 if (fast_clock > 0) { 75 switch(clock_id) { 76 case CLOCK_UPTIME_FAST: 77 case CLOCK_MONOTONIC_FAST: 78 do { 79 w = *upticksp; 80 cpu_lfence(); 81 *ts = ts_uptime[w & 1]; 82 cpu_lfence(); 83 w = *upticksp - w; 84 } while (w > 1); 85 res = 0; 86 break; 87 case CLOCK_REALTIME_FAST: 88 case CLOCK_SECOND: 89 do { 90 w = *upticksp; 91 cpu_lfence(); 92 *ts = ts_realtime[w & 1]; 93 cpu_lfence(); 94 w = *upticksp - w; 95 } while (w > 1); 96 97 if (clock_id == CLOCK_SECOND) 98 ts->tv_nsec = 0; 99 res = 0; 100 break; 101 default: 102 res = __sys_clock_gettime(clock_id, ts); 103 break; 104 } 105 } else { 106 res = __sys_clock_gettime(clock_id, ts); 107 } 108 return res; 109 } 110 111 __weak_reference(__clock_gettime, clock_gettime); 112