diff options
| author |   Dave Barach <dave@barachs.net> | 2019-12-01 08:59:03 -0500 |
|---|---|---|
| committer |   Florin Coras <florin.coras@gmail.com> | 2019-12-02 23:00:21 +0000 |
| commit | e52d8d880ac644f07154bc2fb94035a198ed6688 (patch) | |
| tree | ffbc53cdc8859504d32a6066b033394936332772 /src/vppinfra/time.h | |
| parent | 5ef9ca6c0de25993bde0dbc354cc4a5bc83ab0eb (diff) | |
vppinfra: preserve total_cpu_time across clock freq adjustment
If clib_time_verify_frequency() adjusts the clock frequency, transform
total_cpu_time to the new time coordinate space. Otherwise, we break
comparisons with previous clib_time_now() value.
Without this correction, time jumps in one direction or the other
depending on the sign of the frequency change. Reasonably harmless in
most cases, but under perfect storm conditions the wheels fall off.
Type: fix
Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I21802c2630e2c87ff817cd732b7d78bc022cd2d7
Diffstat (limited to 'src/vppinfra/time.h')
| -rw-r--r-- | src/vppinfra/time.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/src/vppinfra/time.h b/src/vppinfra/time.h index ae738db1307..b2d749256d3 100644 --- a/src/vppinfra/time.h +++ b/src/vppinfra/time.h @@ -205,14 +205,16 @@ clib_time_now_internal (clib_time_t * c, u64 n) { u64 l = c->last_cpu_time; u64 t = c->total_cpu_time; + f64 rv; t += n - l; c->total_cpu_time = t; c->last_cpu_time = n; + rv = t * c->seconds_per_clock; if (PREDICT_FALSE ((c->last_cpu_time - c->last_verify_cpu_time) >> c->log2_clocks_per_frequency_verify)) clib_time_verify_frequency (c); - return t * c->seconds_per_clock; + return rv; } /* Maximum f64 value as max clib_time */ |