Lines Matching +full:skew +full:- +full:delay
1 // SPDX-License-Identifier: GPL-2.0+
20 #include "tick-internal.h"
27 u64 delta = clocksource_delta(end, start, cs->mask, cs->max_raw_delta); in cycles_to_nsec_safe()
29 if (likely(delta < cs->max_cycles)) in cycles_to_nsec_safe()
30 return clocksource_cyc2ns(delta, cs->mult, cs->shift); in cycles_to_nsec_safe()
32 return mul_u64_u32_shr(delta, cs->mult, cs->shift); in cycles_to_nsec_safe()
36 * clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks
71 sftacc--; in clocks_calc_mult_shift()
78 for (sft = 32; sft > 0; sft--) { in clocks_calc_mult_shift()
90 /*[Clocksource internal variables]---------
100 * Name of the user-specified clocksource.
122 * Maximum permissible delay between two readouts of the watchdog
124 * This delay could be due to SMIs, NMIs, or to VCPU preemptions. Used as
125 * a lower bound for cs->uncertainty_margin values when registering clocks.
131 * precise (for example, with a sub-nanosecond period), the maximum
132 * permissible skew between the clocksource watchdog and the clocksource
144 * Default for maximum permissible skew when cs->uncertainty_margin is
145 * not specified, and the lower bound even when cs->uncertainty_margin
147 * clocks with unspecified cs->uncertainty_margin, so this macro is used
197 list_del(&cs->list); in clocksource_change_rating()
198 cs->rating = rating; in clocksource_change_rating()
204 cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG); in __clocksource_unstable()
205 cs->flags |= CLOCK_SOURCE_UNSTABLE; in __clocksource_unstable()
209 * re-rate and re-select. in __clocksource_unstable()
211 if (list_empty(&cs->list)) { in __clocksource_unstable()
212 cs->rating = 0; in __clocksource_unstable()
216 if (cs->mark_unstable) in __clocksource_unstable()
217 cs->mark_unstable(cs); in __clocksource_unstable()
225 * clocksource_mark_unstable - mark clocksource unstable via watchdog
229 * it defers demotion and re-selection to a kthread.
236 if (!(cs->flags & CLOCK_SOURCE_UNSTABLE)) { in clocksource_mark_unstable()
237 if (!list_empty(&cs->list) && list_empty(&cs->wd_list)) in clocksource_mark_unstable()
238 list_add(&cs->wd_list, &watchdog_list); in clocksource_mark_unstable()
255 int64_t md = 2 * watchdog->uncertainty_margin; in cs_watchdog_read()
263 *wdnow = watchdog->read(watchdog); in cs_watchdog_read()
264 *csnow = cs->read(cs); in cs_watchdog_read()
265 wd_end = watchdog->read(watchdog); in cs_watchdog_read()
266 wd_end2 = watchdog->read(watchdog); in cs_watchdog_read()
270 if (wd_delay <= md + cs->uncertainty_margin) { in cs_watchdog_read()
273 smp_processor_id(), watchdog->name, nretries); in cs_watchdog_read()
279 * Now compute delay in consecutive watchdog read to see if in cs_watchdog_read()
281 * significant delay in reading both clocksource and watchdog. in cs_watchdog_read()
283 * If consecutive WD read-back delay > md, report in cs_watchdog_read()
292 …"timekeeping watchdog on CPU%d: wd-%s-wd excessive read-back delay of %lldns vs. limit of %ldns, w… in cs_watchdog_read()
293 smp_processor_id(), cs->name, wd_delay, WATCHDOG_MAX_SKEW, wd_seq_delay, nretries, cs->name); in cs_watchdog_read()
297 pr_info("timekeeping watchdog on CPU%d: %s wd-wd read-back delay of %lldns\n", in cs_watchdog_read()
298 smp_processor_id(), watchdog->name, wd_seq_delay); in cs_watchdog_read()
299 pr_info("wd-%s-wd read-back delay of %lldns, clock-skew test skipped!\n", in cs_watchdog_read()
300 cs->name, wd_delay); in cs_watchdog_read()
356 csnow_mid = cs->read(cs); in clocksource_verify_one_cpu()
376 pr_warn("Not enough CPUs to check clocksource '%s'.\n", cs->name); in clocksource_verify_percpu()
381 cs->name, testcpu, cpumask_pr_args(&cpus_chosen)); in clocksource_verify_percpu()
386 csnow_begin = cs->read(cs); in clocksource_verify_percpu()
388 csnow_end = cs->read(cs); in clocksource_verify_percpu()
389 delta = (s64)((csnow_mid - csnow_begin) & cs->mask); in clocksource_verify_percpu()
392 delta = (csnow_end - csnow_mid) & cs->mask; in clocksource_verify_percpu()
406 cpumask_pr_args(&cpus_ahead), testcpu, cs->name); in clocksource_verify_percpu()
409 cpumask_pr_args(&cpus_behind), testcpu, cs->name); in clocksource_verify_percpu()
410 pr_info(" CPU %d check durations %lldns - %lldns for clocksource %s.\n", in clocksource_verify_percpu()
411 testcpu, cs_nsec_min, cs_nsec_max, cs->name); in clocksource_verify_percpu()
420 cs->flags &= ~CLOCK_SOURCE_WATCHDOG; in clocksource_reset_watchdog()
443 if (cs->flags & CLOCK_SOURCE_UNSTABLE) { in clocksource_watchdog()
467 * cs->last could keep unchanged for 5 minutes, reset in clocksource_watchdog()
476 if (!(cs->flags & CLOCK_SOURCE_WATCHDOG) || in clocksource_watchdog()
478 cs->flags |= CLOCK_SOURCE_WATCHDOG; in clocksource_watchdog()
479 cs->wd_last = wdnow; in clocksource_watchdog()
480 cs->cs_last = csnow; in clocksource_watchdog()
484 wd_nsec = cycles_to_nsec_safe(watchdog, cs->wd_last, wdnow); in clocksource_watchdog()
485 cs_nsec = cycles_to_nsec_safe(cs, cs->cs_last, csnow); in clocksource_watchdog()
486 wdlast = cs->wd_last; /* save these in case we print them */ in clocksource_watchdog()
487 cslast = cs->cs_last; in clocksource_watchdog()
488 cs->cs_last = csnow; in clocksource_watchdog()
489 cs->wd_last = wdnow; in clocksource_watchdog()
498 * Skew detection may fail for longer watchdog intervals in clocksource_watchdog()
516 md = cs->uncertainty_margin + watchdog->uncertainty_margin; in clocksource_watchdog()
517 if (abs(cs_nsec - wd_nsec) > md) { in clocksource_watchdog()
522 …pr_warn("timekeeping watchdog on CPU%d: Marking clocksource '%s' as unstable because the skew is t… in clocksource_watchdog()
523 smp_processor_id(), cs->name); in clocksource_watchdog()
525 watchdog->name, wd_nsec, wdnow, wdlast, watchdog->mask); in clocksource_watchdog()
527 cs->name, cs_nsec, csnow, cslast, cs->mask); in clocksource_watchdog()
528 cs_wd_msec = div_s64_rem(cs_nsec - wd_nsec, 1000 * 1000, &wd_rem); in clocksource_watchdog()
531 cs->name, cs_nsec - wd_nsec, cs_wd_msec, watchdog->name, wd_nsec, wd_msec); in clocksource_watchdog()
533 pr_warn(" '%s' is current clocksource.\n", cs->name); in clocksource_watchdog()
535 … '%s' (not '%s') is current clocksource.\n", curr_clocksource->name, cs->name); in clocksource_watchdog()
542 if (cs == curr_clocksource && cs->tick_stable) in clocksource_watchdog()
543 cs->tick_stable(cs); in clocksource_watchdog()
545 if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && in clocksource_watchdog()
546 (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) && in clocksource_watchdog()
547 (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) { in clocksource_watchdog()
548 /* Mark it valid for high-res. */ in clocksource_watchdog()
549 cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; in clocksource_watchdog()
567 cs->flags |= CLOCK_SOURCE_RESELECT; in clocksource_watchdog()
625 INIT_LIST_HEAD(&cs->wd_list); in clocksource_enqueue_watchdog()
627 if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) { in clocksource_enqueue_watchdog()
629 list_add(&cs->wd_list, &watchdog_list); in clocksource_enqueue_watchdog()
630 cs->flags &= ~CLOCK_SOURCE_WATCHDOG; in clocksource_enqueue_watchdog()
633 if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) in clocksource_enqueue_watchdog()
634 cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; in clocksource_enqueue_watchdog()
651 if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) in clocksource_select_watchdog()
659 if (!watchdog || cs->rating > watchdog->rating) in clocksource_select_watchdog()
678 if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) { in clocksource_dequeue_watchdog()
680 list_del_init(&cs->wd_list); in clocksource_dequeue_watchdog()
693 /* Do any required per-CPU skew verification. */ in __clocksource_watchdog_kthread()
695 curr_clocksource->flags & CLOCK_SOURCE_UNSTABLE && in __clocksource_watchdog_kthread()
696 curr_clocksource->flags & CLOCK_SOURCE_VERIFY_PERCPU) in __clocksource_watchdog_kthread()
701 if (cs->flags & CLOCK_SOURCE_UNSTABLE) { in __clocksource_watchdog_kthread()
702 list_del_init(&cs->wd_list); in __clocksource_watchdog_kthread()
706 if (cs->flags & CLOCK_SOURCE_RESELECT) { in __clocksource_watchdog_kthread()
707 cs->flags &= ~CLOCK_SOURCE_RESELECT; in __clocksource_watchdog_kthread()
736 if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) in clocksource_enqueue_watchdog()
737 cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; in clocksource_enqueue_watchdog()
762 if (!(cs->flags & CLOCK_SOURCE_SUSPEND_NONSTOP)) in __clocksource_suspend_select()
770 if (cs->suspend || cs->resume) { in __clocksource_suspend_select()
772 cs->name); in __clocksource_suspend_select()
776 if (!suspend_clocksource || cs->rating > suspend_clocksource->rating) in __clocksource_suspend_select()
781 * clocksource_suspend_select - Select the best clocksource for suspend timing
802 * clocksource_start_suspend_timing - Start measuring the suspend timing
810 * that means processes are frozen, non-boot cpus and interrupts are disabled
829 if (suspend_clocksource->enable && in clocksource_start_suspend_timing()
830 suspend_clocksource->enable(suspend_clocksource)) { in clocksource_start_suspend_timing()
831 pr_warn_once("Failed to enable the non-suspend-able clocksource.\n"); in clocksource_start_suspend_timing()
835 suspend_start = suspend_clocksource->read(suspend_clocksource); in clocksource_start_suspend_timing()
839 * clocksource_stop_suspend_timing - Stop measuring the suspend timing
867 now = suspend_clocksource->read(suspend_clocksource); in clocksource_stop_suspend_timing()
876 if (!clocksource_is_suspend(cs) && suspend_clocksource->disable) in clocksource_stop_suspend_timing()
877 suspend_clocksource->disable(suspend_clocksource); in clocksource_stop_suspend_timing()
883 * clocksource_suspend - suspend the clocksource(s)
890 if (cs->suspend) in clocksource_suspend()
891 cs->suspend(cs); in clocksource_suspend()
895 * clocksource_resume - resume the clocksource(s)
902 if (cs->resume) in clocksource_resume()
903 cs->resume(cs); in clocksource_resume()
909 * clocksource_touch_watchdog - Update watchdog
921 * clocksource_max_adjustment- Returns max adjustment amount
931 ret = (u64)cs->mult * 11; in clocksource_max_adjustment()
937 * clocks_calc_max_nsecs - Returns maximum nanoseconds that can be converted
957 * cyc2ns() function without overflowing a 64-bit result. in clocks_calc_max_nsecs()
969 max_nsecs = clocksource_cyc2ns(max_cycles, mult - maxadj, shift); in clocks_calc_max_nsecs()
982 * clocksource_update_max_deferment - Updates the clocksource max_idle_ns & max_cycles
988 cs->max_idle_ns = clocks_calc_max_nsecs(cs->mult, cs->shift, in clocksource_update_max_deferment()
989 cs->maxadj, cs->mask, in clocksource_update_max_deferment()
990 &cs->max_cycles); in clocksource_update_max_deferment()
999 cs->max_raw_delta = (cs->mask >> 1) + (cs->mask >> 2) + (cs->mask >> 3); in clocksource_update_max_deferment()
1017 if (oneshot && !(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES)) in clocksource_find_best()
1041 if (strcmp(cs->name, override_name) != 0) in __clocksource_select()
1044 * Check to make sure we don't switch to a non-highres in __clocksource_select()
1048 if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && oneshot) { in __clocksource_select()
1050 if (cs->flags & CLOCK_SOURCE_UNSTABLE) { in __clocksource_select()
1051 …pr_warn("Override clocksource %s is unstable and not HRT compatible - cannot switch while in HRT/N… in __clocksource_select()
1052 cs->name); in __clocksource_select()
1059 pr_info("Override clocksource %s is not currently HRT compatible - deferring\n", in __clocksource_select()
1060 cs->name); in __clocksource_select()
1070 pr_info("Switched to clocksource %s\n", best->name); in __clocksource_select()
1076 * clocksource_select - Select the best clocksource available
1094 * clocksource_done_booting - Called near the end of core bootup
1125 if (tmp->rating < cs->rating) in clocksource_enqueue()
1127 entry = &tmp->list; in clocksource_enqueue()
1129 list_add(&cs->list, entry); in clocksource_enqueue()
1133 * __clocksource_update_freq_scale - Used update clocksource with new freq
1138 * This should only be called from the clocksource->enable() method.
1149 * Default clocksources are *special* and self-define their mult/shift. in __clocksource_update_freq_scale()
1155 * wrapping around. For clocksources which have a mask > 32-bit in __clocksource_update_freq_scale()
1159 * clocksource with mask >= 40-bit and f >= 4GHz. That maps to in __clocksource_update_freq_scale()
1162 sec = cs->mask; in __clocksource_update_freq_scale()
1167 else if (sec > 600 && cs->mask > UINT_MAX) in __clocksource_update_freq_scale()
1170 clocks_calc_mult_shift(&cs->mult, &cs->shift, freq, in __clocksource_update_freq_scale()
1176 * both scale and freq are non-zero, calculate the clock period, but in __clocksource_update_freq_scale()
1179 * and take the tens-of-milliseconds WATCHDOG_THRESHOLD value in __clocksource_update_freq_scale()
1189 if (scale && freq && !cs->uncertainty_margin) { in __clocksource_update_freq_scale()
1190 cs->uncertainty_margin = NSEC_PER_SEC / (scale * freq); in __clocksource_update_freq_scale()
1191 if (cs->uncertainty_margin < 2 * WATCHDOG_MAX_SKEW) in __clocksource_update_freq_scale()
1192 cs->uncertainty_margin = 2 * WATCHDOG_MAX_SKEW; in __clocksource_update_freq_scale()
1193 } else if (!cs->uncertainty_margin) { in __clocksource_update_freq_scale()
1194 cs->uncertainty_margin = WATCHDOG_THRESHOLD; in __clocksource_update_freq_scale()
1196 WARN_ON_ONCE(cs->uncertainty_margin < 2 * WATCHDOG_MAX_SKEW); in __clocksource_update_freq_scale()
1202 cs->maxadj = clocksource_max_adjustment(cs); in __clocksource_update_freq_scale()
1203 while (freq && ((cs->mult + cs->maxadj < cs->mult) in __clocksource_update_freq_scale()
1204 || (cs->mult - cs->maxadj > cs->mult))) { in __clocksource_update_freq_scale()
1205 cs->mult >>= 1; in __clocksource_update_freq_scale()
1206 cs->shift--; in __clocksource_update_freq_scale()
1207 cs->maxadj = clocksource_max_adjustment(cs); in __clocksource_update_freq_scale()
1211 * Only warn for *special* clocksources that self-define in __clocksource_update_freq_scale()
1214 WARN_ONCE(cs->mult + cs->maxadj < cs->mult, in __clocksource_update_freq_scale()
1216 cs->name); in __clocksource_update_freq_scale()
1221 cs->name, cs->mask, cs->max_cycles, cs->max_idle_ns); in __clocksource_update_freq_scale()
1226 * __clocksource_register_scale - Used to install new clocksources
1231 * Returns -EBUSY if registration fails, zero otherwise.
1242 if (WARN_ON_ONCE((unsigned int)cs->id >= CSID_MAX)) in __clocksource_register_scale()
1243 cs->id = CSID_GENERIC; in __clocksource_register_scale()
1244 if (cs->vdso_clock_mode < 0 || in __clocksource_register_scale()
1245 cs->vdso_clock_mode >= VDSO_CLOCKMODE_MAX) { in __clocksource_register_scale()
1247 cs->name, cs->vdso_clock_mode); in __clocksource_register_scale()
1248 cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE; in __clocksource_register_scale()
1281 return -EBUSY; in clocksource_unbind()
1288 return -EBUSY; in clocksource_unbind()
1302 list_del_init(&cs->list); in clocksource_unbind()
1309 * clocksource_unregister - remove a registered clocksource
1317 if (!list_empty(&cs->list)) in clocksource_unregister()
1326 * current_clocksource_show - sysfs interface for current clocksource
1340 count = sysfs_emit(buf, "%s\n", curr_clocksource->name); in current_clocksource_show()
1352 return -EINVAL; in sysfs_get_uname()
1355 if (buf[cnt-1] == '\n') in sysfs_get_uname()
1356 cnt--; in sysfs_get_uname()
1364 * current_clocksource_store - interface for manually overriding clocksource
1392 * unbind_clocksource_store - interface for manually unbinding clocksource
1412 ret = -ENODEV; in unbind_clocksource_store()
1415 if (strcmp(cs->name, name)) in unbind_clocksource_store()
1427 * available_clocksource_show - sysfs interface for listing clocksource
1444 * Don't show non-HRES clocksource if the tick code is in available_clocksource_show()
1448 (src->flags & CLOCK_SOURCE_VALID_FOR_HRES)) in available_clocksource_show()
1450 max((ssize_t)PAGE_SIZE - count, (ssize_t)0), in available_clocksource_show()
1451 "%s ", src->name); in available_clocksource_show()
1456 max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "\n"); in available_clocksource_show()
1495 * boot_override_clocksource - boot clock override
1513 * boot_override_clock - Compatibility layer for deprecated boot option
1522 pr_warn("clock=pmtmr is deprecated - use clocksource=acpi_pm\n"); in boot_override_clock()
1525 pr_warn("clock= boot option is deprecated - use clocksource=xyz\n"); in boot_override_clock()