diff options
| -rw-r--r-- | src/charts.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/charts.c b/src/charts.c index b4916df..4bb87e2 100644 --- a/src/charts.c +++ b/src/charts.c @@ -54,6 +54,7 @@ typedef struct _vwm_charts_t { /* libvmon */ struct timeval maybe_sample, last_sample, this_sample; + unsigned this_sample_duration; typeof(((vmon_sys_stat_t *)0)->user) last_user_cpu; typeof(((vmon_sys_stat_t *)0)->system) last_system_cpu; unsigned long long last_total, this_total, total_delta; @@ -1272,13 +1273,23 @@ int vwm_charts_update(vwm_charts_t *charts, int *desired_delay_us) charts->sampling_interval <= charts->prev_sampling_interval && this_delta >= (charts->sampling_interval * 1.5)) { + /* adjust charts->this_sample_duration as needed since we've missed our deadline. + * This is more of an issue in headless mode, especially when run on slower/embedded + * devices, even worse when periodically snapshoting costly PNGs that may take + * several seconds during which no sampling occurs. + */ + charts->this_sample_duration = (this_delta / charts->sampling_interval) + .5f /* rounded to int */; + /* require > 1 contiguous drops before lowering the rate, tolerates spurious one-off stalls */ if (++charts->contiguous_drops > 2) vwm_charts_rate_decrease(charts); } else { charts->contiguous_drops = 0; + charts->this_sample_duration = 1; /* ideally always 1, but > 1 when sample deadline missed (repeat sample) */ } + VWM_TRACE("sample_duration=%u", charts->this_sample_duration); + /* age the sys-wide sample data into "last" variables, before the new sample overwrites them. */ charts->last_sample = charts->this_sample; charts->this_sample = charts->maybe_sample; |