stats: Add a way to specify if the data set is a population or a sample

This changes how we compute the variance. We want an unbiased variance
when reasoning about a sample.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/igt_stats.h b/lib/igt_stats.h
index c45c8197..d2c1cc7a 100644
--- a/lib/igt_stats.h
+++ b/lib/igt_stats.h
@@ -38,12 +38,14 @@ typedef struct {
 
 	/*< private >*/
 	unsigned int capacity;
+	unsigned int is_population  : 1;
 	unsigned int mean_variance_valid : 1;
 	double mean, variance;
 } igt_stats_t;
 
 void igt_stats_init(igt_stats_t *stats, unsigned int capacity);
 void igt_stats_fini(igt_stats_t *stats);
+void igt_stats_set_population(igt_stats_t *stats, bool full_population);
 void igt_stats_push(igt_stats_t *stats, uint64_t value);
 double igt_stats_get_mean(igt_stats_t *stats);
 double igt_stats_get_variance(igt_stats_t *stats);