2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
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.
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,
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27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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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
34 * Copyright (c) 1997, 1998 Poul-Henning Kamp <phk@FreeBSD.org>
35 * Copyright (c) 1982, 1986, 1991, 1993
36 * The Regents of the University of California. All rights reserved.
37 * (c) UNIX System Laboratories, Inc.
38 * All or some portions of this file are derived from material licensed
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40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
41 * the permission of UNIX System Laboratories, Inc.
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44 * modification, are permitted provided that the following conditions
46 * 1. Redistributions of source code must retain the above copyright
47 * notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 * notice, this list of conditions and the following disclaimer in the
50 * documentation and/or other materials provided with the distribution.
51 * 3. Neither the name of the University nor the names of its contributors
52 * may be used to endorse or promote products derived from this software
53 * without specific prior written permission.
55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
67 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
68 * $FreeBSD: src/sys/kern/kern_clock.c,v 1.105.2.10 2002/10/17 13:19:40 maxim Exp $
72 #include "opt_ifpoll.h"
73 #include "opt_pctrack.h"
75 #include <sys/param.h>
76 #include <sys/systm.h>
77 #include <sys/callout.h>
78 #include <sys/kernel.h>
79 #include <sys/kinfo.h>
81 #include <sys/malloc.h>
82 #include <sys/resource.h>
83 #include <sys/resourcevar.h>
84 #include <sys/signalvar.h>
86 #include <sys/timex.h>
87 #include <sys/timepps.h>
88 #include <sys/upmap.h>
92 #include <vm/vm_map.h>
93 #include <vm/vm_extern.h>
94 #include <sys/sysctl.h>
96 #include <sys/thread2.h>
97 #include <sys/mplock2.h>
99 #include <machine/cpu.h>
100 #include <machine/limits.h>
101 #include <machine/smp.h>
102 #include <machine/cpufunc.h>
103 #include <machine/specialreg.h>
104 #include <machine/clock.h>
107 #include <sys/gmon.h>
111 extern void ifpoll_init_pcpu(int);
115 static void do_pctrack(struct intrframe
*frame
, int which
);
118 static void initclocks (void *dummy
);
119 SYSINIT(clocks
, SI_BOOT2_CLOCKS
, SI_ORDER_FIRST
, initclocks
, NULL
);
122 * Some of these don't belong here, but it's easiest to concentrate them.
123 * Note that cpu_time counts in microseconds, but most userland programs
124 * just compare relative times against the total by delta.
126 struct kinfo_cputime cputime_percpu
[MAXCPU
];
128 struct kinfo_pcheader cputime_pcheader
= { PCTRACK_SIZE
, PCTRACK_ARYSIZE
};
129 struct kinfo_pctrack cputime_pctrack
[MAXCPU
][PCTRACK_SIZE
];
133 sysctl_cputime(SYSCTL_HANDLER_ARGS
)
137 size_t size
= sizeof(struct kinfo_cputime
);
138 struct kinfo_cputime tmp
;
141 * NOTE: For security reasons, only root can sniff %rip
143 root_error
= priv_check_cred(curthread
->td_ucred
, PRIV_ROOT
, 0);
145 for (cpu
= 0; cpu
< ncpus
; ++cpu
) {
146 tmp
= cputime_percpu
[cpu
];
147 if (root_error
== 0) {
149 (int64_t)globaldata_find(cpu
)->gd_sample_pc
;
151 (int64_t)globaldata_find(cpu
)->gd_sample_sp
;
153 if ((error
= SYSCTL_OUT(req
, &tmp
, size
)) != 0)
162 SYSCTL_PROC(_kern
, OID_AUTO
, cputime
, (CTLTYPE_OPAQUE
|CTLFLAG_RD
), 0, 0,
163 sysctl_cputime
, "S,kinfo_cputime", "CPU time statistics");
166 sysctl_cp_time(SYSCTL_HANDLER_ARGS
)
168 long cpu_states
[5] = {0};
170 size_t size
= sizeof(cpu_states
);
172 for (cpu
= 0; cpu
< ncpus
; ++cpu
) {
173 cpu_states
[CP_USER
] += cputime_percpu
[cpu
].cp_user
;
174 cpu_states
[CP_NICE
] += cputime_percpu
[cpu
].cp_nice
;
175 cpu_states
[CP_SYS
] += cputime_percpu
[cpu
].cp_sys
;
176 cpu_states
[CP_INTR
] += cputime_percpu
[cpu
].cp_intr
;
177 cpu_states
[CP_IDLE
] += cputime_percpu
[cpu
].cp_idle
;
180 error
= SYSCTL_OUT(req
, cpu_states
, size
);
185 SYSCTL_PROC(_kern
, OID_AUTO
, cp_time
, (CTLTYPE_LONG
|CTLFLAG_RD
), 0, 0,
186 sysctl_cp_time
, "LU", "CPU time statistics");
189 * boottime is used to calculate the 'real' uptime. Do not confuse this with
190 * microuptime(). microtime() is not drift compensated. The real uptime
191 * with compensation is nanotime() - bootime. boottime is recalculated
192 * whenever the real time is set based on the compensated elapsed time
193 * in seconds (gd->gd_time_seconds).
195 * The gd_time_seconds and gd_cpuclock_base fields remain fairly monotonic.
196 * Slight adjustments to gd_cpuclock_base are made to phase-lock it to
199 * WARNING! time_second can backstep on time corrections. Also, unlike
200 * time_second, time_uptime is not a "real" time_t (seconds
201 * since the Epoch) but seconds since booting.
203 struct timespec boottime
; /* boot time (realtime) for reference only */
204 time_t time_second
; /* read-only 'passive' realtime in seconds */
205 time_t time_uptime
; /* read-only 'passive' uptime in seconds */
208 * basetime is used to calculate the compensated real time of day. The
209 * basetime can be modified on a per-tick basis by the adjtime(),
210 * ntp_adjtime(), and sysctl-based time correction APIs.
212 * Note that frequency corrections can also be made by adjusting
215 * basetime is a tail-chasing FIFO, updated only by cpu #0. The FIFO is
216 * used on both SMP and UP systems to avoid MP races between cpu's and
217 * interrupt races on UP systems.
220 __uint32_t time_second
;
221 sysclock_t cpuclock_base
;
224 #define BASETIME_ARYSIZE 16
225 #define BASETIME_ARYMASK (BASETIME_ARYSIZE - 1)
226 static struct timespec basetime
[BASETIME_ARYSIZE
];
227 static struct hardtime hardtime
[BASETIME_ARYSIZE
];
228 static volatile int basetime_index
;
231 sysctl_get_basetime(SYSCTL_HANDLER_ARGS
)
238 * Because basetime data and index may be updated by another cpu,
239 * a load fence is required to ensure that the data we read has
240 * not been speculatively read relative to a possibly updated index.
242 index
= basetime_index
;
244 bt
= &basetime
[index
];
245 error
= SYSCTL_OUT(req
, bt
, sizeof(*bt
));
249 SYSCTL_STRUCT(_kern
, KERN_BOOTTIME
, boottime
, CTLFLAG_RD
,
250 &boottime
, timespec
, "System boottime");
251 SYSCTL_PROC(_kern
, OID_AUTO
, basetime
, CTLTYPE_STRUCT
|CTLFLAG_RD
, 0, 0,
252 sysctl_get_basetime
, "S,timespec", "System basetime");
254 static void hardclock(systimer_t info
, int, struct intrframe
*frame
);
255 static void statclock(systimer_t info
, int, struct intrframe
*frame
);
256 static void schedclock(systimer_t info
, int, struct intrframe
*frame
);
257 static void getnanotime_nbt(struct timespec
*nbt
, struct timespec
*tsp
);
259 int ticks
; /* system master ticks at hz */
260 int clocks_running
; /* tsleep/timeout clocks operational */
261 int64_t nsec_adj
; /* ntpd per-tick adjustment in nsec << 32 */
262 int64_t nsec_acc
; /* accumulator */
263 int sched_ticks
; /* global schedule clock ticks */
265 /* NTPD time correction fields */
266 int64_t ntp_tick_permanent
; /* per-tick adjustment in nsec << 32 */
267 int64_t ntp_tick_acc
; /* accumulator for per-tick adjustment */
268 int64_t ntp_delta
; /* one-time correction in nsec */
269 int64_t ntp_big_delta
= 1000000000;
270 int32_t ntp_tick_delta
; /* current adjustment rate */
271 int32_t ntp_default_tick_delta
; /* adjustment rate for ntp_delta */
272 time_t ntp_leap_second
; /* time of next leap second */
273 int ntp_leap_insert
; /* whether to insert or remove a second */
276 * Finish initializing clock frequencies and start all clocks running.
280 initclocks(void *dummy
)
282 /*psratio = profhz / stathz;*/
286 kpmap
->tsc_freq
= (uint64_t)tsc_frequency
;
287 kpmap
->tick_freq
= hz
;
292 * Called on a per-cpu basis from the idle thread bootstrap on each cpu
293 * during SMP initialization.
295 * This routine is called concurrently during low-level SMP initialization
296 * and may not block in any way. Meaning, among other things, we can't
297 * acquire any tokens.
300 initclocks_pcpu(void)
302 struct globaldata
*gd
= mycpu
;
305 if (gd
->gd_cpuid
== 0) {
306 gd
->gd_time_seconds
= 1;
307 gd
->gd_cpuclock_base
= sys_cputimer
->count();
308 hardtime
[0].time_second
= gd
->gd_time_seconds
;
309 hardtime
[0].cpuclock_base
= gd
->gd_cpuclock_base
;
311 gd
->gd_time_seconds
= globaldata_find(0)->gd_time_seconds
;
312 gd
->gd_cpuclock_base
= globaldata_find(0)->gd_cpuclock_base
;
315 systimer_intr_enable();
321 * This routine is called on just the BSP, just after SMP initialization
322 * completes to * finish initializing any clocks that might contend/block
323 * (e.g. like on a token). We can't do this in initclocks_pcpu() because
324 * that function is called from the idle thread bootstrap for each cpu and
325 * not allowed to block at all.
329 initclocks_other(void *dummy
)
331 struct globaldata
*ogd
= mycpu
;
332 struct globaldata
*gd
;
335 for (n
= 0; n
< ncpus
; ++n
) {
336 lwkt_setcpu_self(globaldata_find(n
));
340 * Use a non-queued periodic systimer to prevent multiple
341 * ticks from building up if the sysclock jumps forward
342 * (8254 gets reset). The sysclock will never jump backwards.
343 * Our time sync is based on the actual sysclock, not the
346 systimer_init_periodic_nq(&gd
->gd_hardclock
, hardclock
,
348 systimer_init_periodic_nq(&gd
->gd_statclock
, statclock
,
350 /* XXX correct the frequency for scheduler / estcpu tests */
351 systimer_init_periodic_nq(&gd
->gd_schedclock
, schedclock
,
354 ifpoll_init_pcpu(gd
->gd_cpuid
);
357 lwkt_setcpu_self(ogd
);
359 SYSINIT(clocks2
, SI_BOOT2_POST_SMP
, SI_ORDER_ANY
, initclocks_other
, NULL
);
362 * This sets the current real time of day. Timespecs are in seconds and
363 * nanoseconds. We do not mess with gd_time_seconds and gd_cpuclock_base,
364 * instead we adjust basetime so basetime + gd_* results in the current
365 * time of day. This way the gd_* fields are guaranteed to represent
366 * a monotonically increasing 'uptime' value.
368 * When set_timeofday() is called from userland, the system call forces it
369 * onto cpu #0 since only cpu #0 can update basetime_index.
372 set_timeofday(struct timespec
*ts
)
374 struct timespec
*nbt
;
378 * XXX SMP / non-atomic basetime updates
381 ni
= (basetime_index
+ 1) & BASETIME_ARYMASK
;
385 nbt
->tv_sec
= ts
->tv_sec
- nbt
->tv_sec
;
386 nbt
->tv_nsec
= ts
->tv_nsec
- nbt
->tv_nsec
;
387 if (nbt
->tv_nsec
< 0) {
388 nbt
->tv_nsec
+= 1000000000;
393 * Note that basetime diverges from boottime as the clock drift is
394 * compensated for, so we cannot do away with boottime. When setting
395 * the absolute time of day the drift is 0 (for an instant) and we
396 * can simply assign boottime to basetime.
398 * Note that nanouptime() is based on gd_time_seconds which is drift
399 * compensated up to a point (it is guaranteed to remain monotonically
400 * increasing). gd_time_seconds is thus our best uptime guess and
401 * suitable for use in the boottime calculation. It is already taken
402 * into account in the basetime calculation above.
404 boottime
.tv_sec
= nbt
->tv_sec
;
408 * We now have a new basetime, make sure all other cpus have it,
409 * then update the index.
418 * Each cpu has its own hardclock, but we only increments ticks and softticks
421 * NOTE! systimer! the MP lock might not be held here. We can only safely
422 * manipulate objects owned by the current cpu.
425 hardclock(systimer_t info
, int in_ipi
, struct intrframe
*frame
)
429 struct globaldata
*gd
= mycpu
;
431 if ((gd
->gd_reqflags
& RQF_IPIQ
) == 0 && lwkt_need_ipiq_process(gd
)) {
432 /* Defer to doreti on passive IPIQ processing */
437 * We update the compensation base to calculate fine-grained time
438 * from the sys_cputimer on a per-cpu basis in order to avoid
439 * having to mess around with locks. sys_cputimer is assumed to
440 * be consistent across all cpus. CPU N copies the base state from
441 * CPU 0 using the same FIFO trick that we use for basetime (so we
442 * don't catch a CPU 0 update in the middle).
444 * Note that we never allow info->time (aka gd->gd_hardclock.time)
445 * to reverse index gd_cpuclock_base, but that it is possible for
446 * it to temporarily get behind in the seconds if something in the
447 * system locks interrupts for a long period of time. Since periodic
448 * timers count events, though everything should resynch again
451 if (gd
->gd_cpuid
== 0) {
454 cputicks
= info
->time
- gd
->gd_cpuclock_base
;
455 if (cputicks
>= sys_cputimer
->freq
) {
456 cputicks
/= sys_cputimer
->freq
;
457 if (cputicks
!= 0 && cputicks
!= 1)
458 kprintf("Warning: hardclock missed > 1 sec\n");
459 gd
->gd_time_seconds
+= cputicks
;
460 gd
->gd_cpuclock_base
+= sys_cputimer
->freq
* cputicks
;
461 /* uncorrected monotonic 1-sec gran */
462 time_uptime
+= cputicks
;
464 ni
= (basetime_index
+ 1) & BASETIME_ARYMASK
;
465 hardtime
[ni
].time_second
= gd
->gd_time_seconds
;
466 hardtime
[ni
].cpuclock_base
= gd
->gd_cpuclock_base
;
472 gd
->gd_time_seconds
= hardtime
[ni
].time_second
;
473 gd
->gd_cpuclock_base
= hardtime
[ni
].cpuclock_base
;
477 * The system-wide ticks counter and NTP related timedelta/tickdelta
478 * adjustments only occur on cpu #0. NTP adjustments are accomplished
479 * by updating basetime.
481 if (gd
->gd_cpuid
== 0) {
482 struct timespec
*nbt
;
490 if (tco
->tc_poll_pps
)
491 tco
->tc_poll_pps(tco
);
495 * Calculate the new basetime index. We are in a critical section
496 * on cpu #0 and can safely play with basetime_index. Start
497 * with the current basetime and then make adjustments.
499 ni
= (basetime_index
+ 1) & BASETIME_ARYMASK
;
501 *nbt
= basetime
[basetime_index
];
504 * Apply adjtime corrections. (adjtime() API)
506 * adjtime() only runs on cpu #0 so our critical section is
507 * sufficient to access these variables.
509 if (ntp_delta
!= 0) {
510 nbt
->tv_nsec
+= ntp_tick_delta
;
511 ntp_delta
-= ntp_tick_delta
;
512 if ((ntp_delta
> 0 && ntp_delta
< ntp_tick_delta
) ||
513 (ntp_delta
< 0 && ntp_delta
> ntp_tick_delta
)) {
514 ntp_tick_delta
= ntp_delta
;
519 * Apply permanent frequency corrections. (sysctl API)
521 if (ntp_tick_permanent
!= 0) {
522 ntp_tick_acc
+= ntp_tick_permanent
;
523 if (ntp_tick_acc
>= (1LL << 32)) {
524 nbt
->tv_nsec
+= ntp_tick_acc
>> 32;
525 ntp_tick_acc
-= (ntp_tick_acc
>> 32) << 32;
526 } else if (ntp_tick_acc
<= -(1LL << 32)) {
527 /* Negate ntp_tick_acc to avoid shifting the sign bit. */
528 nbt
->tv_nsec
-= (-ntp_tick_acc
) >> 32;
529 ntp_tick_acc
+= ((-ntp_tick_acc
) >> 32) << 32;
533 if (nbt
->tv_nsec
>= 1000000000) {
535 nbt
->tv_nsec
-= 1000000000;
536 } else if (nbt
->tv_nsec
< 0) {
538 nbt
->tv_nsec
+= 1000000000;
542 * Another per-tick compensation. (for ntp_adjtime() API)
545 nsec_acc
+= nsec_adj
;
546 if (nsec_acc
>= 0x100000000LL
) {
547 nbt
->tv_nsec
+= nsec_acc
>> 32;
548 nsec_acc
= (nsec_acc
& 0xFFFFFFFFLL
);
549 } else if (nsec_acc
<= -0x100000000LL
) {
550 nbt
->tv_nsec
-= -nsec_acc
>> 32;
551 nsec_acc
= -(-nsec_acc
& 0xFFFFFFFFLL
);
553 if (nbt
->tv_nsec
>= 1000000000) {
554 nbt
->tv_nsec
-= 1000000000;
556 } else if (nbt
->tv_nsec
< 0) {
557 nbt
->tv_nsec
+= 1000000000;
562 /************************************************************
563 * LEAP SECOND CORRECTION *
564 ************************************************************
566 * Taking into account all the corrections made above, figure
567 * out the new real time. If the seconds field has changed
568 * then apply any pending leap-second corrections.
570 getnanotime_nbt(nbt
, &nts
);
572 if (time_second
!= nts
.tv_sec
) {
574 * Apply leap second (sysctl API). Adjust nts for changes
575 * so we do not have to call getnanotime_nbt again.
577 if (ntp_leap_second
) {
578 if (ntp_leap_second
== nts
.tv_sec
) {
579 if (ntp_leap_insert
) {
591 * Apply leap second (ntp_adjtime() API), calculate a new
592 * nsec_adj field. ntp_update_second() returns nsec_adj
593 * as a per-second value but we need it as a per-tick value.
595 leap
= ntp_update_second(time_second
, &nsec_adj
);
601 * Update the time_second 'approximate time' global.
603 time_second
= nts
.tv_sec
;
607 * Finally, our new basetime is ready to go live!
613 * Update kpmap on each tick. TS updates are integrated with
614 * fences and upticks allowing userland to read the data
620 w
= (kpmap
->upticks
+ 1) & 1;
621 getnanouptime(&kpmap
->ts_uptime
[w
]);
622 getnanotime(&kpmap
->ts_realtime
[w
]);
630 * lwkt thread scheduler fair queueing
632 lwkt_schedulerclock(curthread
);
635 * softticks are handled for all cpus
637 hardclock_softtick(gd
);
640 * ITimer handling is per-tick, per-cpu.
642 * We must acquire the per-process token in order for ksignal()
643 * to be non-blocking. For the moment this requires an AST fault,
644 * the ksignal() cannot be safely issued from this hard interrupt.
646 * XXX Even the trytoken here isn't right, and itimer operation in
647 * a multi threaded environment is going to be weird at the
650 if ((p
= curproc
) != NULL
&& lwkt_trytoken(&p
->p_token
)) {
653 ++p
->p_upmap
->runticks
;
655 if (frame
&& CLKF_USERMODE(frame
) &&
656 timevalisset(&p
->p_timer
[ITIMER_VIRTUAL
].it_value
) &&
657 itimerdecr(&p
->p_timer
[ITIMER_VIRTUAL
], ustick
) == 0) {
658 p
->p_flags
|= P_SIGVTALRM
;
661 if (timevalisset(&p
->p_timer
[ITIMER_PROF
].it_value
) &&
662 itimerdecr(&p
->p_timer
[ITIMER_PROF
], ustick
) == 0) {
663 p
->p_flags
|= P_SIGPROF
;
667 lwkt_reltoken(&p
->p_token
);
673 * The statistics clock typically runs at a 125Hz rate, and is intended
674 * to be frequency offset from the hardclock (typ 100Hz). It is per-cpu.
676 * NOTE! systimer! the MP lock might not be held here. We can only safely
677 * manipulate objects owned by the current cpu.
679 * The stats clock is responsible for grabbing a profiling sample.
680 * Most of the statistics are only used by user-level statistics programs.
681 * The main exceptions are p->p_uticks, p->p_sticks, p->p_iticks, and
684 * Like the other clocks, the stat clock is called from what is effectively
685 * a fast interrupt, so the context should be the thread/process that got
689 statclock(systimer_t info
, int in_ipi
, struct intrframe
*frame
)
702 * How big was our timeslice relative to the last time? Calculate
705 * NOTE: Use of microuptime() is typically MPSAFE, but usually not
706 * during early boot. Just use the systimer count to be nice
707 * to e.g. qemu. The systimer has a better chance of being
708 * MPSAFE at early boot.
710 cv
= sys_cputimer
->count();
711 scv
= mycpu
->statint
.gd_statcv
;
715 bump
= (sys_cputimer
->freq64_usec
* (cv
- scv
)) >> 32;
721 mycpu
->statint
.gd_statcv
= cv
;
724 stv
= &mycpu
->gd_stattv
;
725 if (stv
->tv_sec
== 0) {
728 bump
= tv
.tv_usec
- stv
->tv_usec
+
729 (tv
.tv_sec
- stv
->tv_sec
) * 1000000;
741 if (frame
&& CLKF_USERMODE(frame
)) {
743 * Came from userland, handle user time and deal with
746 if (p
&& (p
->p_flags
& P_PROFIL
))
747 addupc_intr(p
, CLKF_PC(frame
), 1);
748 td
->td_uticks
+= bump
;
751 * Charge the time as appropriate
753 if (p
&& p
->p_nice
> NZERO
)
754 cpu_time
.cp_nice
+= bump
;
756 cpu_time
.cp_user
+= bump
;
758 int intr_nest
= mycpu
->gd_intr_nesting_level
;
762 * IPI processing code will bump gd_intr_nesting_level
763 * up by one, which breaks following CLKF_INTR testing,
764 * so we subtract it by one here.
770 * Kernel statistics are just like addupc_intr, only easier.
773 if (g
->state
== GMON_PROF_ON
&& frame
) {
774 i
= CLKF_PC(frame
) - g
->lowpc
;
775 if (i
< g
->textsize
) {
776 i
/= HISTFRACTION
* sizeof(*g
->kcount
);
782 #define IS_INTR_RUNNING ((frame && CLKF_INTR(intr_nest)) || CLKF_INTR_TD(td))
785 * Came from kernel mode, so we were:
786 * - handling an interrupt,
787 * - doing syscall or trap work on behalf of the current
789 * - spinning in the idle loop.
790 * Whichever it is, charge the time as appropriate.
791 * Note that we charge interrupts to the current process,
792 * regardless of whether they are ``for'' that process,
793 * so that we know how much of its real time was spent
794 * in ``non-process'' (i.e., interrupt) work.
796 * XXX assume system if frame is NULL. A NULL frame
797 * can occur if ipi processing is done from a crit_exit().
800 td
->td_iticks
+= bump
;
802 td
->td_sticks
+= bump
;
804 if (IS_INTR_RUNNING
) {
806 * If we interrupted an interrupt thread, well,
807 * count it as interrupt time.
811 do_pctrack(frame
, PCTRACK_INT
);
813 cpu_time
.cp_intr
+= bump
;
815 if (td
== &mycpu
->gd_idlethread
) {
817 * Even if the current thread is the idle
818 * thread it could be due to token contention
819 * in the LWKT scheduler. Count such as
822 if (mycpu
->gd_reqflags
& RQF_IDLECHECK_WK_MASK
)
823 cpu_time
.cp_sys
+= bump
;
825 cpu_time
.cp_idle
+= bump
;
828 * System thread was running.
832 do_pctrack(frame
, PCTRACK_SYS
);
834 cpu_time
.cp_sys
+= bump
;
838 #undef IS_INTR_RUNNING
844 * Sample the PC when in the kernel or in an interrupt. User code can
845 * retrieve the information and generate a histogram or other output.
849 do_pctrack(struct intrframe
*frame
, int which
)
851 struct kinfo_pctrack
*pctrack
;
853 pctrack
= &cputime_pctrack
[mycpu
->gd_cpuid
][which
];
854 pctrack
->pc_array
[pctrack
->pc_index
& PCTRACK_ARYMASK
] =
855 (void *)CLKF_PC(frame
);
860 sysctl_pctrack(SYSCTL_HANDLER_ARGS
)
862 struct kinfo_pcheader head
;
867 head
.pc_ntrack
= PCTRACK_SIZE
;
868 head
.pc_arysize
= PCTRACK_ARYSIZE
;
870 if ((error
= SYSCTL_OUT(req
, &head
, sizeof(head
))) != 0)
873 for (cpu
= 0; cpu
< ncpus
; ++cpu
) {
874 for (ntrack
= 0; ntrack
< PCTRACK_SIZE
; ++ntrack
) {
875 error
= SYSCTL_OUT(req
, &cputime_pctrack
[cpu
][ntrack
],
876 sizeof(struct kinfo_pctrack
));
885 SYSCTL_PROC(_kern
, OID_AUTO
, pctrack
, (CTLTYPE_OPAQUE
|CTLFLAG_RD
), 0, 0,
886 sysctl_pctrack
, "S,kinfo_pcheader", "CPU PC tracking");
891 * The scheduler clock typically runs at a 50Hz rate. NOTE! systimer,
892 * the MP lock might not be held. We can safely manipulate parts of curproc
893 * but that's about it.
895 * Each cpu has its own scheduler clock.
898 schedclock(systimer_t info
, int in_ipi __unused
, struct intrframe
*frame
)
905 if ((lp
= lwkt_preempted_proc()) != NULL
) {
907 * Account for cpu time used and hit the scheduler. Note
908 * that this call MUST BE MP SAFE, and the BGL IS NOT HELD
912 usched_schedulerclock(lp
, info
->periodic
, info
->time
);
914 usched_schedulerclock(NULL
, info
->periodic
, info
->time
);
916 if ((lp
= curthread
->td_lwp
) != NULL
) {
918 * Update resource usage integrals and maximums.
920 if ((ru
= &lp
->lwp_proc
->p_ru
) &&
921 (vm
= lp
->lwp_proc
->p_vmspace
) != NULL
) {
922 ru
->ru_ixrss
+= pgtok(vm
->vm_tsize
);
923 ru
->ru_idrss
+= pgtok(vm
->vm_dsize
);
924 ru
->ru_isrss
+= pgtok(vm
->vm_ssize
);
925 if (lwkt_trytoken(&vm
->vm_map
.token
)) {
926 rss
= pgtok(vmspace_resident_count(vm
));
927 if (ru
->ru_maxrss
< rss
)
929 lwkt_reltoken(&vm
->vm_map
.token
);
933 /* Increment the global sched_ticks */
934 if (mycpu
->gd_cpuid
== 0)
939 * Compute number of ticks for the specified amount of time. The
940 * return value is intended to be used in a clock interrupt timed
941 * operation and guaranteed to meet or exceed the requested time.
942 * If the representation overflows, return INT_MAX. The minimum return
943 * value is 1 ticks and the function will average the calculation up.
944 * If any value greater then 0 microseconds is supplied, a value
945 * of at least 2 will be returned to ensure that a near-term clock
946 * interrupt does not cause the timeout to occur (degenerately) early.
948 * Note that limit checks must take into account microseconds, which is
949 * done simply by using the smaller signed long maximum instead of
950 * the unsigned long maximum.
952 * If ints have 32 bits, then the maximum value for any timeout in
953 * 10ms ticks is 248 days.
956 tvtohz_high(struct timeval
*tv
)
973 kprintf("tvtohz_high: negative time difference "
974 "%ld sec %ld usec\n",
978 } else if (sec
<= INT_MAX
/ hz
) {
979 ticks
= (int)(sec
* hz
+
980 ((u_long
)usec
+ (ustick
- 1)) / ustick
) + 1;
988 tstohz_high(struct timespec
*ts
)
1005 kprintf("tstohz_high: negative time difference "
1006 "%ld sec %ld nsec\n",
1010 } else if (sec
<= INT_MAX
/ hz
) {
1011 ticks
= (int)(sec
* hz
+
1012 ((u_long
)nsec
+ (nstick
- 1)) / nstick
) + 1;
1021 * Compute number of ticks for the specified amount of time, erroring on
1022 * the side of it being too low to ensure that sleeping the returned number
1023 * of ticks will not result in a late return.
1025 * The supplied timeval may not be negative and should be normalized. A
1026 * return value of 0 is possible if the timeval converts to less then
1029 * If ints have 32 bits, then the maximum value for any timeout in
1030 * 10ms ticks is 248 days.
1033 tvtohz_low(struct timeval
*tv
)
1039 if (sec
<= INT_MAX
/ hz
)
1040 ticks
= (int)(sec
* hz
+ (u_long
)tv
->tv_usec
/ ustick
);
1047 tstohz_low(struct timespec
*ts
)
1053 if (sec
<= INT_MAX
/ hz
)
1054 ticks
= (int)(sec
* hz
+ (u_long
)ts
->tv_nsec
/ nstick
);
1061 * Start profiling on a process.
1063 * Kernel profiling passes proc0 which never exits and hence
1064 * keeps the profile clock running constantly.
1067 startprofclock(struct proc
*p
)
1069 if ((p
->p_flags
& P_PROFIL
) == 0) {
1070 p
->p_flags
|= P_PROFIL
;
1072 if (++profprocs
== 1 && stathz
!= 0) {
1075 setstatclockrate(profhz
);
1083 * Stop profiling on a process.
1085 * caller must hold p->p_token
1088 stopprofclock(struct proc
*p
)
1090 if (p
->p_flags
& P_PROFIL
) {
1091 p
->p_flags
&= ~P_PROFIL
;
1093 if (--profprocs
== 0 && stathz
!= 0) {
1096 setstatclockrate(stathz
);
1104 * Return information about system clocks.
1107 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS
)
1109 struct kinfo_clockinfo clkinfo
;
1111 * Construct clockinfo structure.
1114 clkinfo
.ci_tick
= ustick
;
1115 clkinfo
.ci_tickadj
= ntp_default_tick_delta
/ 1000;
1116 clkinfo
.ci_profhz
= profhz
;
1117 clkinfo
.ci_stathz
= stathz
? stathz
: hz
;
1118 return (sysctl_handle_opaque(oidp
, &clkinfo
, sizeof clkinfo
, req
));
1121 SYSCTL_PROC(_kern
, KERN_CLOCKRATE
, clockrate
, CTLTYPE_STRUCT
|CTLFLAG_RD
,
1122 0, 0, sysctl_kern_clockrate
, "S,clockinfo","");
1125 * We have eight functions for looking at the clock, four for
1126 * microseconds and four for nanoseconds. For each there is fast
1127 * but less precise version "get{nano|micro}[up]time" which will
1128 * return a time which is up to 1/HZ previous to the call, whereas
1129 * the raw version "{nano|micro}[up]time" will return a timestamp
1130 * which is as precise as possible. The "up" variants return the
1131 * time relative to system boot, these are well suited for time
1132 * interval measurements.
1134 * Each cpu independently maintains the current time of day, so all
1135 * we need to do to protect ourselves from changes is to do a loop
1136 * check on the seconds field changing out from under us.
1138 * The system timer maintains a 32 bit count and due to various issues
1139 * it is possible for the calculated delta to occasionally exceed
1140 * sys_cputimer->freq. If this occurs the sys_cputimer->freq64_nsec
1141 * multiplication can easily overflow, so we deal with the case. For
1142 * uniformity we deal with the case in the usec case too.
1144 * All the [get][micro,nano][time,uptime]() routines are MPSAFE.
1147 getmicrouptime(struct timeval
*tvp
)
1149 struct globaldata
*gd
= mycpu
;
1153 tvp
->tv_sec
= gd
->gd_time_seconds
;
1154 delta
= gd
->gd_hardclock
.time
- gd
->gd_cpuclock_base
;
1155 } while (tvp
->tv_sec
!= gd
->gd_time_seconds
);
1157 if (delta
>= sys_cputimer
->freq
) {
1158 tvp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1159 delta
%= sys_cputimer
->freq
;
1161 tvp
->tv_usec
= (sys_cputimer
->freq64_usec
* delta
) >> 32;
1162 if (tvp
->tv_usec
>= 1000000) {
1163 tvp
->tv_usec
-= 1000000;
1169 getnanouptime(struct timespec
*tsp
)
1171 struct globaldata
*gd
= mycpu
;
1175 tsp
->tv_sec
= gd
->gd_time_seconds
;
1176 delta
= gd
->gd_hardclock
.time
- gd
->gd_cpuclock_base
;
1177 } while (tsp
->tv_sec
!= gd
->gd_time_seconds
);
1179 if (delta
>= sys_cputimer
->freq
) {
1180 tsp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1181 delta
%= sys_cputimer
->freq
;
1183 tsp
->tv_nsec
= (sys_cputimer
->freq64_nsec
* delta
) >> 32;
1187 microuptime(struct timeval
*tvp
)
1189 struct globaldata
*gd
= mycpu
;
1193 tvp
->tv_sec
= gd
->gd_time_seconds
;
1194 delta
= sys_cputimer
->count() - gd
->gd_cpuclock_base
;
1195 } while (tvp
->tv_sec
!= gd
->gd_time_seconds
);
1197 if (delta
>= sys_cputimer
->freq
) {
1198 tvp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1199 delta
%= sys_cputimer
->freq
;
1201 tvp
->tv_usec
= (sys_cputimer
->freq64_usec
* delta
) >> 32;
1205 nanouptime(struct timespec
*tsp
)
1207 struct globaldata
*gd
= mycpu
;
1211 tsp
->tv_sec
= gd
->gd_time_seconds
;
1212 delta
= sys_cputimer
->count() - gd
->gd_cpuclock_base
;
1213 } while (tsp
->tv_sec
!= gd
->gd_time_seconds
);
1215 if (delta
>= sys_cputimer
->freq
) {
1216 tsp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1217 delta
%= sys_cputimer
->freq
;
1219 tsp
->tv_nsec
= (sys_cputimer
->freq64_nsec
* delta
) >> 32;
1226 getmicrotime(struct timeval
*tvp
)
1228 struct globaldata
*gd
= mycpu
;
1229 struct timespec
*bt
;
1233 tvp
->tv_sec
= gd
->gd_time_seconds
;
1234 delta
= gd
->gd_hardclock
.time
- gd
->gd_cpuclock_base
;
1235 } while (tvp
->tv_sec
!= gd
->gd_time_seconds
);
1237 if (delta
>= sys_cputimer
->freq
) {
1238 tvp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1239 delta
%= sys_cputimer
->freq
;
1241 tvp
->tv_usec
= (sys_cputimer
->freq64_usec
* delta
) >> 32;
1243 bt
= &basetime
[basetime_index
];
1245 tvp
->tv_sec
+= bt
->tv_sec
;
1246 tvp
->tv_usec
+= bt
->tv_nsec
/ 1000;
1247 while (tvp
->tv_usec
>= 1000000) {
1248 tvp
->tv_usec
-= 1000000;
1254 getnanotime(struct timespec
*tsp
)
1256 struct globaldata
*gd
= mycpu
;
1257 struct timespec
*bt
;
1261 tsp
->tv_sec
= gd
->gd_time_seconds
;
1262 delta
= gd
->gd_hardclock
.time
- gd
->gd_cpuclock_base
;
1263 } while (tsp
->tv_sec
!= gd
->gd_time_seconds
);
1265 if (delta
>= sys_cputimer
->freq
) {
1266 tsp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1267 delta
%= sys_cputimer
->freq
;
1269 tsp
->tv_nsec
= (sys_cputimer
->freq64_nsec
* delta
) >> 32;
1271 bt
= &basetime
[basetime_index
];
1273 tsp
->tv_sec
+= bt
->tv_sec
;
1274 tsp
->tv_nsec
+= bt
->tv_nsec
;
1275 while (tsp
->tv_nsec
>= 1000000000) {
1276 tsp
->tv_nsec
-= 1000000000;
1282 getnanotime_nbt(struct timespec
*nbt
, struct timespec
*tsp
)
1284 struct globaldata
*gd
= mycpu
;
1288 tsp
->tv_sec
= gd
->gd_time_seconds
;
1289 delta
= gd
->gd_hardclock
.time
- gd
->gd_cpuclock_base
;
1290 } while (tsp
->tv_sec
!= gd
->gd_time_seconds
);
1292 if (delta
>= sys_cputimer
->freq
) {
1293 tsp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1294 delta
%= sys_cputimer
->freq
;
1296 tsp
->tv_nsec
= (sys_cputimer
->freq64_nsec
* delta
) >> 32;
1298 tsp
->tv_sec
+= nbt
->tv_sec
;
1299 tsp
->tv_nsec
+= nbt
->tv_nsec
;
1300 while (tsp
->tv_nsec
>= 1000000000) {
1301 tsp
->tv_nsec
-= 1000000000;
1308 microtime(struct timeval
*tvp
)
1310 struct globaldata
*gd
= mycpu
;
1311 struct timespec
*bt
;
1315 tvp
->tv_sec
= gd
->gd_time_seconds
;
1316 delta
= sys_cputimer
->count() - gd
->gd_cpuclock_base
;
1317 } while (tvp
->tv_sec
!= gd
->gd_time_seconds
);
1319 if (delta
>= sys_cputimer
->freq
) {
1320 tvp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1321 delta
%= sys_cputimer
->freq
;
1323 tvp
->tv_usec
= (sys_cputimer
->freq64_usec
* delta
) >> 32;
1325 bt
= &basetime
[basetime_index
];
1327 tvp
->tv_sec
+= bt
->tv_sec
;
1328 tvp
->tv_usec
+= bt
->tv_nsec
/ 1000;
1329 while (tvp
->tv_usec
>= 1000000) {
1330 tvp
->tv_usec
-= 1000000;
1336 nanotime(struct timespec
*tsp
)
1338 struct globaldata
*gd
= mycpu
;
1339 struct timespec
*bt
;
1343 tsp
->tv_sec
= gd
->gd_time_seconds
;
1344 delta
= sys_cputimer
->count() - gd
->gd_cpuclock_base
;
1345 } while (tsp
->tv_sec
!= gd
->gd_time_seconds
);
1347 if (delta
>= sys_cputimer
->freq
) {
1348 tsp
->tv_sec
+= delta
/ sys_cputimer
->freq
;
1349 delta
%= sys_cputimer
->freq
;
1351 tsp
->tv_nsec
= (sys_cputimer
->freq64_nsec
* delta
) >> 32;
1353 bt
= &basetime
[basetime_index
];
1355 tsp
->tv_sec
+= bt
->tv_sec
;
1356 tsp
->tv_nsec
+= bt
->tv_nsec
;
1357 while (tsp
->tv_nsec
>= 1000000000) {
1358 tsp
->tv_nsec
-= 1000000000;
1364 * Get an approximate time_t. It does not have to be accurate. This
1365 * function is called only from KTR and can be called with the system in
1366 * any state so do not use a critical section or other complex operation
1369 * NOTE: This is not exactly synchronized with real time. To do that we
1370 * would have to do what microtime does and check for a nanoseconds
1374 get_approximate_time_t(void)
1376 struct globaldata
*gd
= mycpu
;
1377 struct timespec
*bt
;
1379 bt
= &basetime
[basetime_index
];
1380 return(gd
->gd_time_seconds
+ bt
->tv_sec
);
1384 pps_ioctl(u_long cmd
, caddr_t data
, struct pps_state
*pps
)
1387 struct pps_fetch_args
*fapi
;
1389 struct pps_kcbind_args
*kapi
;
1393 case PPS_IOC_CREATE
:
1395 case PPS_IOC_DESTROY
:
1397 case PPS_IOC_SETPARAMS
:
1398 app
= (pps_params_t
*)data
;
1399 if (app
->mode
& ~pps
->ppscap
)
1401 pps
->ppsparam
= *app
;
1403 case PPS_IOC_GETPARAMS
:
1404 app
= (pps_params_t
*)data
;
1405 *app
= pps
->ppsparam
;
1406 app
->api_version
= PPS_API_VERS_1
;
1408 case PPS_IOC_GETCAP
:
1409 *(int*)data
= pps
->ppscap
;
1412 fapi
= (struct pps_fetch_args
*)data
;
1413 if (fapi
->tsformat
&& fapi
->tsformat
!= PPS_TSFMT_TSPEC
)
1415 if (fapi
->timeout
.tv_sec
|| fapi
->timeout
.tv_nsec
)
1416 return (EOPNOTSUPP
);
1417 pps
->ppsinfo
.current_mode
= pps
->ppsparam
.mode
;
1418 fapi
->pps_info_buf
= pps
->ppsinfo
;
1420 case PPS_IOC_KCBIND
:
1422 kapi
= (struct pps_kcbind_args
*)data
;
1423 /* XXX Only root should be able to do this */
1424 if (kapi
->tsformat
&& kapi
->tsformat
!= PPS_TSFMT_TSPEC
)
1426 if (kapi
->kernel_consumer
!= PPS_KC_HARDPPS
)
1428 if (kapi
->edge
& ~pps
->ppscap
)
1430 pps
->kcmode
= kapi
->edge
;
1433 return (EOPNOTSUPP
);
1441 pps_init(struct pps_state
*pps
)
1443 pps
->ppscap
|= PPS_TSFMT_TSPEC
;
1444 if (pps
->ppscap
& PPS_CAPTUREASSERT
)
1445 pps
->ppscap
|= PPS_OFFSETASSERT
;
1446 if (pps
->ppscap
& PPS_CAPTURECLEAR
)
1447 pps
->ppscap
|= PPS_OFFSETCLEAR
;
1451 pps_event(struct pps_state
*pps
, sysclock_t count
, int event
)
1453 struct globaldata
*gd
;
1454 struct timespec
*tsp
;
1455 struct timespec
*osp
;
1456 struct timespec
*bt
;
1472 /* Things would be easier with arrays... */
1473 if (event
== PPS_CAPTUREASSERT
) {
1474 tsp
= &pps
->ppsinfo
.assert_timestamp
;
1475 osp
= &pps
->ppsparam
.assert_offset
;
1476 foff
= pps
->ppsparam
.mode
& PPS_OFFSETASSERT
;
1478 fhard
= pps
->kcmode
& PPS_CAPTUREASSERT
;
1480 pcount
= &pps
->ppscount
[0];
1481 pseq
= &pps
->ppsinfo
.assert_sequence
;
1483 tsp
= &pps
->ppsinfo
.clear_timestamp
;
1484 osp
= &pps
->ppsparam
.clear_offset
;
1485 foff
= pps
->ppsparam
.mode
& PPS_OFFSETCLEAR
;
1487 fhard
= pps
->kcmode
& PPS_CAPTURECLEAR
;
1489 pcount
= &pps
->ppscount
[1];
1490 pseq
= &pps
->ppsinfo
.clear_sequence
;
1493 /* Nothing really happened */
1494 if (*pcount
== count
)
1500 ts
.tv_sec
= gd
->gd_time_seconds
;
1501 delta
= count
- gd
->gd_cpuclock_base
;
1502 } while (ts
.tv_sec
!= gd
->gd_time_seconds
);
1504 if (delta
>= sys_cputimer
->freq
) {
1505 ts
.tv_sec
+= delta
/ sys_cputimer
->freq
;
1506 delta
%= sys_cputimer
->freq
;
1508 ts
.tv_nsec
= (sys_cputimer
->freq64_nsec
* delta
) >> 32;
1509 ni
= basetime_index
;
1512 ts
.tv_sec
+= bt
->tv_sec
;
1513 ts
.tv_nsec
+= bt
->tv_nsec
;
1514 while (ts
.tv_nsec
>= 1000000000) {
1515 ts
.tv_nsec
-= 1000000000;
1523 timespecadd(tsp
, osp
);
1524 if (tsp
->tv_nsec
< 0) {
1525 tsp
->tv_nsec
+= 1000000000;
1531 /* magic, at its best... */
1532 tcount
= count
- pps
->ppscount
[2];
1533 pps
->ppscount
[2] = count
;
1534 if (tcount
>= sys_cputimer
->freq
) {
1535 delta
= (1000000000 * (tcount
/ sys_cputimer
->freq
) +
1536 sys_cputimer
->freq64_nsec
*
1537 (tcount
% sys_cputimer
->freq
)) >> 32;
1539 delta
= (sys_cputimer
->freq64_nsec
* tcount
) >> 32;
1541 hardpps(tsp
, delta
);
1547 * Return the tsc target value for a delay of (ns).
1549 * Returns -1 if the TSC is not supported.
1552 tsc_get_target(int ns
)
1554 #if defined(_RDTSC_SUPPORTED_)
1555 if (cpu_feature
& CPUID_TSC
) {
1556 return (rdtsc() + tsc_frequency
* ns
/ (int64_t)1000000000);
1563 * Compare the tsc against the passed target
1565 * Returns +1 if the target has been reached
1566 * Returns 0 if the target has not yet been reached
1567 * Returns -1 if the TSC is not supported.
1569 * Typical use: while (tsc_test_target(target) == 0) { ...poll... }
1572 tsc_test_target(int64_t target
)
1574 #if defined(_RDTSC_SUPPORTED_)
1575 if (cpu_feature
& CPUID_TSC
) {
1576 if ((int64_t)(target
- rdtsc()) <= 0)
1585 * Delay the specified number of nanoseconds using the tsc. This function
1586 * returns immediately if the TSC is not supported. At least one cpu_pause()
1594 clk
= tsc_get_target(ns
);
1596 while (tsc_test_target(clk
) == 0)