diff options
Diffstat (limited to 'usr/src/uts/i86pc/os/timestamp.c')
| -rw-r--r-- | usr/src/uts/i86pc/os/timestamp.c | 62 |
1 files changed, 58 insertions, 4 deletions
diff --git a/usr/src/uts/i86pc/os/timestamp.c b/usr/src/uts/i86pc/os/timestamp.c index 7344e1a492..bce08717dc 100644 --- a/usr/src/uts/i86pc/os/timestamp.c +++ b/usr/src/uts/i86pc/os/timestamp.c @@ -25,7 +25,7 @@ * * Copyright 2012 Nexenta Systems, Inc. All rights reserved. * Copyright (c) 2014, 2016 by Delphix. All rights reserved. - * Copyright 2016 Joyent, Inc. + * Copyright 2018 Joyent, Inc. */ #include <sys/types.h> @@ -280,10 +280,64 @@ tsc_gethrtime_tick_delta(void) return (hrt); } +/* Calculate the hrtime while exposing the parameters of that calculation. */ +hrtime_t +tsc_gethrtime_params(uint64_t *tscp, uint32_t *scalep, uint8_t *shiftp) +{ + uint32_t old_hres_lock, scale; + hrtime_t tsc, last, base; + + do { + old_hres_lock = hres_lock; + + if (gethrtimef == tsc_gethrtime_delta) { + ulong_t flags; + + flags = clear_int_flag(); + tsc = tsc_read() + tsc_sync_tick_delta[CPU->cpu_id]; + restore_int_flag(flags); + } else { + tsc = tsc_read(); + } + + last = tsc_last; + base = tsc_hrtime_base; + scale = nsec_scale; + + } while ((old_hres_lock & ~1) != hres_lock); + + /* See comments in tsc_gethrtime() above */ + if (tsc >= last) { + tsc -= last; + } else if (tsc >= last - 2 * tsc_max_delta) { + tsc = 0; + } else { + tsc = tsc_protect(tsc); + } + + TSC_CONVERT_AND_ADD(tsc, base, nsec_scale); + + if (tscp != NULL) { + /* + * Do not simply communicate the delta applied to the hrtime + * base, but rather the effective TSC measurement. + */ + *tscp = tsc + last; + } + if (scalep != NULL) { + *scalep = scale; + } + if (shiftp != NULL) { + *shiftp = NSEC_SHIFT; + } + + return (base); +} + /* - * This is similar to the above, but it cannot actually spin on hres_lock. - * As a result, it caches all of the variables it needs; if the variables - * don't change, it's done. + * This is similar to tsc_gethrtime_delta, but it cannot actually spin on + * hres_lock. As a result, it caches all of the variables it needs; if the + * variables don't change, it's done. */ hrtime_t dtrace_gethrtime(void) |