diff options
Diffstat (limited to 'kernel/time/sched_clock.c')
| -rw-r--r-- | kernel/time/sched_clock.c | 63 |
1 files changed, 32 insertions, 31 deletions
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index 0abb3646428..01d2d15aa66 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -49,13 +49,6 @@ static u64 notrace jiffy_sched_clock_read(void) return (u64)(jiffies - INITIAL_JIFFIES); } -static u32 __read_mostly (*read_sched_clock_32)(void); - -static u64 notrace read_sched_clock_32_wrapper(void) -{ - return read_sched_clock_32(); -} - static u64 __read_mostly (*read_sched_clock)(void) = jiffy_sched_clock_read; static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift) @@ -116,20 +109,42 @@ static enum hrtimer_restart sched_clock_poll(struct hrtimer *hrt) void __init sched_clock_register(u64 (*read)(void), int bits, unsigned long rate) { + u64 res, wrap, new_mask, new_epoch, cyc, ns; + u32 new_mult, new_shift; + ktime_t new_wrap_kt; unsigned long r; - u64 res, wrap; char r_unit; if (cd.rate > rate) return; WARN_ON(!irqs_disabled()); - read_sched_clock = read; - sched_clock_mask = CLOCKSOURCE_MASK(bits); - cd.rate = rate; /* calculate the mult/shift to convert counter ticks to ns. */ - clocks_calc_mult_shift(&cd.mult, &cd.shift, rate, NSEC_PER_SEC, 3600); + clocks_calc_mult_shift(&new_mult, &new_shift, rate, NSEC_PER_SEC, 3600); + + new_mask = CLOCKSOURCE_MASK(bits); + + /* calculate how many ns until we wrap */ + wrap = clocks_calc_max_nsecs(new_mult, new_shift, 0, new_mask); + new_wrap_kt = ns_to_ktime(wrap - (wrap >> 3)); + + /* update epoch for new counter and update epoch_ns from old counter*/ + new_epoch = read(); + cyc = read_sched_clock(); + ns = cd.epoch_ns + cyc_to_ns((cyc - cd.epoch_cyc) & sched_clock_mask, + cd.mult, cd.shift); + + raw_write_seqcount_begin(&cd.seq); + read_sched_clock = read; + sched_clock_mask = new_mask; + cd.rate = rate; + cd.wrap_kt = new_wrap_kt; + cd.mult = new_mult; + cd.shift = new_shift; + cd.epoch_cyc = new_epoch; + cd.epoch_ns = ns; + raw_write_seqcount_end(&cd.seq); r = rate; if (r >= 4000000) { @@ -141,22 +156,12 @@ void __init sched_clock_register(u64 (*read)(void), int bits, } else r_unit = ' '; - /* calculate how many ns until we wrap */ - wrap = clocks_calc_max_nsecs(cd.mult, cd.shift, 0, sched_clock_mask); - cd.wrap_kt = ns_to_ktime(wrap - (wrap >> 3)); - /* calculate the ns resolution of this counter */ - res = cyc_to_ns(1ULL, cd.mult, cd.shift); + res = cyc_to_ns(1ULL, new_mult, new_shift); + pr_info("sched_clock: %u bits at %lu%cHz, resolution %lluns, wraps every %lluns\n", bits, r, r_unit, res, wrap); - update_sched_clock(); - - /* - * Ensure that sched_clock() starts off at 0ns - */ - cd.epoch_ns = 0; - /* Enable IRQ time accounting if we have a fast enough sched_clock */ if (irqtime > 0 || (irqtime == -1 && rate >= 1000000)) enable_sched_clock_irqtime(); @@ -164,12 +169,6 @@ void __init sched_clock_register(u64 (*read)(void), int bits, pr_debug("Registered %pF as sched_clock source\n", read); } -void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate) -{ - read_sched_clock_32 = read; - sched_clock_register(read_sched_clock_32_wrapper, bits, rate); -} - void __init sched_clock_postinit(void) { /* @@ -192,7 +191,8 @@ void __init sched_clock_postinit(void) static int sched_clock_suspend(void) { - sched_clock_poll(&sched_clock_timer); + update_sched_clock(); + hrtimer_cancel(&sched_clock_timer); cd.suspended = true; return 0; } @@ -200,6 +200,7 @@ static int sched_clock_suspend(void) static void sched_clock_resume(void) { cd.epoch_cyc = read_sched_clock(); + hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL); cd.suspended = false; } |