diff options
Diffstat (limited to 'src/vppinfra/time.c')
| -rw-r--r-- | src/vppinfra/time.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/vppinfra/time.c b/src/vppinfra/time.c index e9a764bcd31..d647e670dad 100644 --- a/src/vppinfra/time.c +++ b/src/vppinfra/time.c @@ -197,6 +197,7 @@ clib_time_verify_frequency (clib_time_t * c) f64 dtr = now_reference - c->last_verify_reference_time; f64 dtr_max; u64 dtc = c->last_cpu_time - c->last_verify_cpu_time; + f64 new_clocks_per_second, delta; f64 round_units = 100e5; c->last_verify_cpu_time = c->last_cpu_time; @@ -217,6 +218,25 @@ clib_time_verify_frequency (clib_time_t * c) return; } + /* + * Reject large frequency changes, another consequence of + * system clock changes particularly with old kernels. + */ + new_clocks_per_second = + flt_round_nearest ((f64) dtc / (dtr * round_units)) * round_units; + + delta = new_clocks_per_second - c->clocks_per_second; + if (delta < 0.0) + delta = -delta; + + if (PREDICT_FALSE ((delta / c->clocks_per_second) > .01)) + { + clib_warning ("Rejecting large frequency change of %.2f%%", + (delta / c->clocks_per_second) * 100.0); + c->log2_clocks_per_frequency_verify = c->log2_clocks_per_second; + return; + } + c->clocks_per_second = flt_round_nearest ((f64) dtc / (dtr * round_units)) * round_units; c->seconds_per_clock = 1 / c->clocks_per_second; |