+ /* Here we check if the max PME rank load is more than 0.98
+ * the max PP force load. If so, PP DLB will not help,
+ * since we are (almost) limited by PME. Furthermore,
+ * DLB will cause a significant extra x/f redistribution
+ * cost on the PME ranks, which will then surely result
+ * in lower total performance.
+ * This check might be fragile, since one measurement
+ * below 0.98 (although only done once every 100 DD part.)
+ * could turn on DLB for the rest of the run.
+ */
+ if (cr->npmenodes > 0 &&
+ dd_pme_f_ratio(dd) > 1 - DD_PERF_LOSS_DLB_ON)
+ {
+ bTurnOnDLB = FALSE;
+ }
+ else
+ {
+ bTurnOnDLB =
+ (dd_force_imb_perf_loss(dd) >= DD_PERF_LOSS_DLB_ON);
+ }