diff options
| -rw-r--r-- | src/til.c | 16 |
1 files changed, 14 insertions, 2 deletions
@@ -662,10 +662,22 @@ int til_module_setup_finalize(const til_module_t *module, const til_settings_t * } -/* generic fragmenter using a horizontal slice per cpu according to context->n_cpus */ +/* generic fragmenter using a horizontal slice per cpu according to context->n_cpus (multiplied by a constant factor) */ int til_fragmenter_slice_per_cpu(til_module_context_t *context, const til_fb_fragment_t *fragment, unsigned number, til_fb_fragment_t *res_fragment) { - return til_fb_fragment_slice_single(fragment, context->n_cpus, number, res_fragment); + /* The *16 is to combat leaving CPUs idle waiting for others to finish their work. + * + * Even though there's some overhead in scheduling smaller work units, + * this still tends to result in better aggregate CPU utilization, up + * to a point. The cost of rendering slices is often inconsistent, + * and there's always a delay from one thread to another getting + * started on their work, as well as scheduling variance. + * + * So it's beneficial to enable early finishers to pick + * up slack of the laggards via slightly more granular + * work units. + */ + return til_fb_fragment_slice_single(fragment, context->n_cpus * 16, number, res_fragment); } |